Searching for a particular memory block by id is an O(n) operation because
each memory block's underlying device is kept in an unsorted linked list
on the subsystem bus.
We can cut the lookup cost to O(log n) if we cache each memory block
in an xarray. This time complexity improvement is significant on
systems with many memory blocks. For example:
1. A 128GB POWER9 VM with 256MB memblocks has 512 blocks. With this
change memory_dev_init() completes ~12ms faster and walk_memory_blocks()
completes ~12ms faster.
Before:
[ 0.005042] memory_dev_init: adding memory blocks
[ 0.021591] memory_dev_init: added memory blocks
[ 0.022699] walk_memory_blocks: walking memory blocks
[ 0.038730] walk_memory_blocks: walked memory blocks 0-511
After:
[ 0.005057] memory_dev_init: adding memory blocks
[ 0.009415] memory_dev_init: added memory blocks
[ 0.010519] walk_memory_blocks: walking memory blocks
[ 0.014135] walk_memory_blocks: walked memory blocks 0-511
2. A 256GB POWER9 LPAR with 256MB memblocks has 1024 blocks. With
this change memory_dev_init() completes ~88ms faster and
walk_memory_blocks() completes ~87ms faster.
Before:
[ 0.252246] memory_dev_init: adding memory blocks
[ 0.395469] memory_dev_init: added memory blocks
[ 0.409413] walk_memory_blocks: walking memory blocks
[ 0.433028] walk_memory_blocks: walked memory blocks 0-511
[ 0.433094] walk_memory_blocks: walking memory blocks
[ 0.500244] walk_memory_blocks: walked memory blocks 131072-131583
After:
[ 0.245063] memory_dev_init: adding memory blocks
[ 0.299539] memory_dev_init: added memory blocks
[ 0.313609] walk_memory_blocks: walking memory blocks
[ 0.315287] walk_memory_blocks: walked memory blocks 0-511
[ 0.315349] walk_memory_blocks: walking memory blocks
[ 0.316988] walk_memory_blocks: walked memory blocks 131072-131583
3. A 32TB POWER9 LPAR with 256MB memblocks has 131072 blocks. With
this change we complete memory_dev_init() ~37 minutes faster and
walk_memory_blocks() at least ~30 minutes faster. The exact timing
for walk_memory_blocks() is missing, though I observed that the
soft lockups in walk_memory_blocks() disappeared with the change,
suggesting that lower bound.
Before:
[ 13.703907] memory_dev_init: adding blocks
[ 2287.406099] memory_dev_init: added all blocks
[ 2347.494986] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2527.625378] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2707.761977] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2887.899975] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3068.028318] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3248.158764] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3428.287296] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3608.425357] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3788.554572] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3968.695071] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 4148.823970] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
After:
[ 13.696898] memory_dev_init: adding blocks
[ 15.660035] memory_dev_init: added all blocks
(the walk_memory_blocks traces disappear)
There should be no significant negative impact for machines with few
memory blocks. A sparse xarray has a small footprint and an O(log n)
lookup is negligibly slower than an O(n) lookup for only the smallest
number of memory blocks.
1. A 16GB x86 machine with 128MB memblocks has 132 blocks. With this
change memory_dev_init() completes ~300us faster and walk_memory_blocks()
completes no faster or slower. The improvement is pretty close to noise.
Before:
[ 0.224752] memory_dev_init: adding memory blocks
[ 0.227116] memory_dev_init: added memory blocks
[ 0.227183] walk_memory_blocks: walking memory blocks
[ 0.227183] walk_memory_blocks: walked memory blocks 0-131
After:
[ 0.224911] memory_dev_init: adding memory blocks
[ 0.226935] memory_dev_init: added memory blocks
[ 0.227089] walk_memory_blocks: walking memory blocks
[ 0.227089] walk_memory_blocks: walked memory blocks 0-131
[david@redhat.com: document the locking]
Link: http://lkml.kernel.org/r/bc21eec6-7251-4c91-2f57-9a0671f8d414@redhat.com
Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200121231028.13699-1-cheloha@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For now, distributions implement advanced udev rules to essentially
- Don't online any hotplugged memory (s390x)
- Online all memory to ZONE_NORMAL (e.g., most virt environments like
hyperv)
- Online all memory to ZONE_MOVABLE in case the zone imbalance is taken
care of (e.g., bare metal, special virt environments)
In summary: All memory is usually onlined the same way, however, the
kernel always has to ask user space to come up with the same answer.
E.g., Hyper-V always waits for a memory block to get onlined before
continuing, otherwise it might end up adding memory faster than
onlining it, which can result in strange OOM situations. This waiting
slows down adding of a bigger amount of memory.
Let's allow to specify a default online_type, not just "online" and
"offline". This allows distributions to configure the default online_type
when booting up and be done with it.
We can now specify "offline", "online", "online_movable" and
"online_kernel" via
- "memhp_default_state=" on the kernel cmdline
- /sys/devices/system/memory/auto_online_blocks
just like we are able to specify for a single memory block via
/sys/devices/system/memory/memoryX/state
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-9-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... and rename it to memhp_default_online_type. This is a preparation
for more detailed default online behavior.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-8-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's use a simple array which we can reuse soon. While at it, move the
string->mmop conversion out of the device hotplug lock.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-4-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Historically, we used the value -1. Just treat 0 as the special case now.
Clarify a comment (which was wrong, when we come via device_online() the
first time, the online_type would have been 0 / MEM_ONLINE). The default
is now always MMOP_OFFLINE. This removes the last user of the manual
"-1", which didn't use the enum value.
This is a preparation to use the online_type as an array index.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Yumei Huang <yuhuang@redhat.com>
Link: http://lkml.kernel.org/r/20200317104942.11178-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memory_hotplug: allow to specify a default online_type", v3.
Distributions nowadays use udev rules ([1] [2]) to specify if and how to
online hotplugged memory. The rules seem to get more complex with many
special cases. Due to the various special cases,
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE cannot be used. All memory hotplug
is handled via udev rules.
Every time we hotplug memory, the udev rule will come to the same
conclusion. Especially Hyper-V (but also soon virtio-mem) add a lot of
memory in separate memory blocks and wait for memory to get onlined by
user space before continuing to add more memory blocks (to not add memory
faster than it is getting onlined). This of course slows down the whole
memory hotplug process.
To make the job of distributions easier and to avoid udev rules that get
more and more complicated, let's extend the mechanism provided by
- /sys/devices/system/memory/auto_online_blocks
- "memhp_default_state=" on the kernel cmdline
to be able to specify also "online_movable" as well as "online_kernel"
=== Example /usr/libexec/config-memhotplug ===
#!/bin/bash
VIRT=`systemd-detect-virt --vm`
ARCH=`uname -p`
sense_virtio_mem() {
if [ -d "/sys/bus/virtio/drivers/virtio_mem/" ]; then
DEVICES=`find /sys/bus/virtio/drivers/virtio_mem/ -maxdepth 1 -type l | wc -l`
if [ $DEVICES != "0" ]; then
return 0
fi
fi
return 1
}
if [ ! -e "/sys/devices/system/memory/auto_online_blocks" ]; then
echo "Memory hotplug configuration support missing in the kernel"
exit 1
fi
if grep "memhp_default_state=" /proc/cmdline > /dev/null; then
echo "Memory hotplug configuration overridden in kernel cmdline (memhp_default_state=)"
exit 1
fi
if [ $VIRT == "microsoft" ]; then
echo "Detected Hyper-V on $ARCH"
# Hyper-V wants all memory in ZONE_NORMAL
ONLINE_TYPE="online_kernel"
elif sense_virtio_mem; then
echo "Detected virtio-mem on $ARCH"
# virtio-mem wants all memory in ZONE_NORMAL
ONLINE_TYPE="online_kernel"
elif [ $ARCH == "s390x" ] || [ $ARCH == "s390" ]; then
echo "Detected $ARCH"
# standby memory should not be onlined automatically
ONLINE_TYPE="offline"
elif [ $ARCH == "ppc64" ] || [ $ARCH == "ppc64le" ]; then
echo "Detected" $ARCH
# PPC64 onlines all hotplugged memory right from the kernel
ONLINE_TYPE="offline"
elif [ $VIRT == "none" ]; then
echo "Detected bare-metal on $ARCH"
# Bare metal users expect hotplugged memory to be unpluggable. We assume
# that ZONE imbalances on such enterpise servers cannot happen and is
# properly documented
ONLINE_TYPE="online_movable"
else
# TODO: Hypervisors that want to unplug DIMMs and can guarantee that ZONE
# imbalances won't happen
echo "Detected $VIRT on $ARCH"
# Usually, ballooning is used in virtual environments, so memory should go to
# ZONE_NORMAL. However, sometimes "movable_node" is relevant.
ONLINE_TYPE="online"
fi
echo "Selected online_type:" $ONLINE_TYPE
# Configure what to do with memory that will be hotplugged in the future
echo $ONLINE_TYPE 2>/dev/null > /sys/devices/system/memory/auto_online_blocks
if [ $? != "0" ]; then
echo "Memory hotplug cannot be configured (e.g., old kernel or missing permissions)"
# A backup udev rule should handle old kernels if necessary
exit 1
fi
# Process all already pluggedd blocks (e.g., DIMMs, but also Hyper-V or virtio-mem)
if [ $ONLINE_TYPE != "offline" ]; then
for MEMORY in /sys/devices/system/memory/memory*; do
STATE=`cat $MEMORY/state`
if [ $STATE == "offline" ]; then
echo $ONLINE_TYPE > $MEMORY/state
fi
done
fi
=== Example /usr/lib/systemd/system/config-memhotplug.service ===
[Unit]
Description=Configure memory hotplug behavior
DefaultDependencies=no
Conflicts=shutdown.target
Before=sysinit.target shutdown.target
After=systemd-modules-load.service
ConditionPathExists=|/sys/devices/system/memory/auto_online_blocks
[Service]
ExecStart=/usr/libexec/config-memhotplug
Type=oneshot
TimeoutSec=0
RemainAfterExit=yes
[Install]
WantedBy=sysinit.target
=== Example modification to the 40-redhat.rules [2] ===
: diff --git a/40-redhat.rules b/40-redhat.rules-new
: index 2c690e5..168fd03 100644
: --- a/40-redhat.rules
: +++ b/40-redhat.rules-new
: @@ -6,6 +6,9 @@ SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}
: # Memory hotadd request
: SUBSYSTEM!="memory", GOTO="memory_hotplug_end"
: ACTION!="add", GOTO="memory_hotplug_end"
: +# memory hotplug behavior configured
: +PROGRAM=="grep online /sys/devices/system/memory/auto_online_blocks", GOTO="memory_hotplug_end"
: +
: PROGRAM="/bin/uname -p", RESULT=="s390*", GOTO="memory_hotplug_end"
:
: ENV{.state}="online"
===
[1] https://github.com/lnykryn/systemd-rhel/pull/281
[2] https://github.com/lnykryn/systemd-rhel/blob/staging/rules/40-redhat.rules
This patch (of 8):
The name is misleading and it's not really clear what is "kept". Let's
just name it like the online_type name we expose to user space ("online").
Add some documentation to the types.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Yumei Huang <yuhuang@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Link: http://lkml.kernel.org/r/20200319131221.14044-1-david@redhat.com
Link: http://lkml.kernel.org/r/20200317104942.11178-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pages_correctly_probed() is a leftover from ancient times. It dates back
to commit 3947be1969 ("[PATCH] memory hotplug: sysfs and add/remove
functions"), where Pg_reserved checks were added as a sfety net:
/*
* The probe routines leave the pages reserved, just
* as the bootmem code does. Make sure they're still
* that way.
*/
The checks were refactored quite a bit over the years, especially in
commit b77eab7079 ("mm/memory_hotplug: optimize probe routine"), where
checks for present, valid, and online sections were added.
Hotplugged memory is added via add_memory(), which will create the full
memmap for the hotplugged memory, and mark all sections valid and present.
Only full memory blocks are onlined/offlined, so we also cannot have an
inconsistency in that regard (especially, memory blocks with some sections
being online and some being offline).
1. Boot memory always starts online. Since commit c5e79ef561
("mm/memory_hotplug.c: don't allow to online/offline memory blocks with
holes") we disallow to offline any memory with holes. Therefore, we
never online memory with holes. Present and validity checks are
superfluous.
2. Only complete memory blocks are onlined/offlined (and especially,
the state - online or offline - is stored for whole memory blocks).
Besides the core, only arch/powerpc/platforms/powernv/memtrace.c
manually calls offline_pages() and fiddels with memory block states.
But it also only offlines complete memory blocks.
3. To make any of these conditions trigger, something would have to be
terribly messed up in the core. (e.g., online/offline only some
sections of a memory block).
4. Memory unplug properly makes sure that all sysfs attributes were
removed (and therefore, that all threads left the sysfs handlers). We
don't have to worry about zombie devices at this point.
5. The valid_section_nr(section_nr) check is actually dead code, as it
would never have been reached due to the WARN_ON_ONCE(!pfn_valid(pfn)).
No wonder we haven't seen any of these errors in a long time (or even
ever, according to my search). Let's just get rid of them. Now, all
checks that could hinder onlining and offlining are completely
contained in online_pages()/offline_pages().
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: http://lkml.kernel.org/r/20200127110424.5757-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: drop superfluous section checks when onlining/offlining".
Let's drop some superfluous section checks on the onlining/offlining path.
This patch (of 3):
Since commit c5e79ef561 ("mm/memory_hotplug.c: don't allow to
online/offline memory blocks with holes") we have a generic check in
offline_pages() that disallows offlining memory blocks with holes.
Memory blocks with missing sections are just another variant of these type
of blocks. We can stop checking (and especially storing) present
sections. A proper error message is now printed why offlining failed.
section_count was initially introduced in commit 0768121597 ("Driver
core: Add section count to memory_block struct") in order to detect when
it is okay to remove a memory block. It was used in commit 26bbe7ef6d
("drivers/base/memory.c: prohibit offlining of memory blocks with missing
sections") to disallow offlining memory blocks with missing sections. As
we refactored creation/removal of memory devices and have a proper check
for holes in place, we can drop the section_count.
This also removes a leftover comment regarding the mem_sysfs_mutex, which
was removed in commit 848e19ad3c ("drivers/base/memory.c: drop the
mem_sysfs_mutex").
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: http://lkml.kernel.org/r/20200127110424.5757-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We see multiple issues with the implementation/interface to compute
whether a memory block can be offlined (exposed via
/sys/devices/system/memory/memoryX/removable) and would like to simplify
it (remove the implementation).
1. It runs basically lockless. While this might be good for performance,
we see possible races with memory offlining that will require at
least some sort of locking to fix.
2. Nowadays, more false positives are possible. No arch-specific checks
are performed that validate if memory offlining will not be denied
right away (and such check will require locking). For example, arm64
won't allow to offline any memory block that was added during boot -
which will imply a very high error rate. Other archs have other
constraints.
3. The interface is inherently racy. E.g., if a memory block is detected
to be removable (and was not a false positive at that time), there is
still no guarantee that offlining will actually succeed. So any
caller already has to deal with false positives.
4. It is unclear which performance benefit this interface actually
provides. The introducing commit 5c755e9fd8 ("memory-hotplug: add
sysfs removable attribute for hotplug memory remove") mentioned
"A user-level agent must be able to identify which sections
of memory are likely to be removable before attempting the
potentially expensive operation."
However, no actual performance comparison was included.
Known users:
- lsmem: Will group memory blocks based on the "removable" property. [1]
- chmem: Indirect user. It has a RANGE mode where one can specify
removable ranges identified via lsmem to be offlined. However,
it also has a "SIZE" mode, which allows a sysadmin to skip the
manual "identify removable blocks" step. [2]
- powerpc-utils: Uses the "removable" attribute to skip some memory
blocks right away when trying to find some to offline+remove.
However, with ballooning enabled, it already skips this
information completely (because it once resulted in many false
negatives). Therefore, the implementation can deal with false
positives properly already. [3]
According to Nathan Fontenot, DLPAR on powerpc is nowadays no longer
driven from userspace via the drmgr command (powerpc-utils). Nowadays
it's managed in the kernel - including onlining/offlining of memory
blocks - triggered by drmgr writing to /sys/kernel/dlpar. So the
affected legacy userspace handling is only active on old kernels. Only
very old versions of drmgr on a new kernel (unlikely) might execute
slower - totally acceptable.
With CONFIG_MEMORY_HOTREMOVE, always indicating "removable" should not
break any user space tool. We implement a very bad heuristic now.
Without CONFIG_MEMORY_HOTREMOVE we cannot offline anything, so report
"not removable" as before.
Original discussion can be found in [4] ("[PATCH RFC v1] mm:
is_mem_section_removable() overhaul").
Other users of is_mem_section_removable() will be removed next, so that
we can remove is_mem_section_removable() completely.
[1] http://man7.org/linux/man-pages/man1/lsmem.1.html
[2] http://man7.org/linux/man-pages/man8/chmem.8.html
[3] https://github.com/ibm-power-utilities/powerpc-utils
[4] https://lkml.kernel.org/r/20200117105759.27905-1-david@redhat.com
Also, this patch probably fixes a crash reported by Steve.
http://lkml.kernel.org/r/CAPcyv4jpdaNvJ67SkjyUJLBnBnXXQv686BiVW042g03FUmWLXw@mail.gmail.com
Reported-by: "Scargall, Steve" <steve.scargall@intel.com>
Suggested-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Nathan Fontenot <ndfont@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Karel Zak <kzak@redhat.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200128093542.6908-1-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The callers are only interested in the actual zone, they don't care about
boundaries. Return the zone instead to simplify.
Link: http://lkml.kernel.org/r/20200110183308.11849-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/memory_hotplug: pass in nid to online_pages()".
Simplify onlining code and get rid of find_memory_block(). Pass in the
nid from the memory block we are trying to online directly, instead of
manually looking it up.
This patch (of 2):
No need to lookup the memory block, we can directly pass in the nid.
Link: http://lkml.kernel.org/r/20200113113354.6341-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Luckily, we have no users left, so we can get rid of it. Cleanup
set_migratetype_isolate() a little bit.
Link: http://lkml.kernel.org/r/20191114131911.11783-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mem_sysfs_mutex isn't really helpful. Also, it's not really clear
what the mutex protects at all.
The device lists of the memory subsystem are protected separately. We
don't need that mutex when looking up. creating, or removing
independent devices. find_memory_block_by_id() will perform locking on
its own and grab a reference of the returned device.
At the time memory_dev_init() is called, we cannot have concurrent
hot(un)plug operations yet - we're still fairly early during boot. We
don't need any locking.
The creation/removal of memory block devices should be protected on a
higher level - especially using the device hotplug lock to avoid
documented issues (see Documentation/core-api/memory-hotplug.rst) - or
if that is reworked, using similar locking.
Protecting in the context of these functions only doesn't really make
sense. Especially, if we would have a situation where the same memory
blocks are created/deleted at the same time, there is something horribly
going wrong (imagining adding/removing a DIMM at the same time from two
call paths) - after the functions succeeded something else in the
callers would blow up (e.g., create_memory_block_devices() succeeded but
there are no memory block devices anymore).
All relevant call paths (except when adding memory early during boot via
ACPI, which is now documented) hold the device hotplug lock when adding
memory, and when removing memory. Let's document that instead.
Add a simple safety net to create_memory_block_devices() in case we
would actually remove memory blocks while adding them, so we'll never
dereference a NULL pointer. Simplify memory_dev_init() now that the
lock is gone.
Link: http://lkml.kernel.org/r/20190925082621.4927-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently soft_offline_page() receives struct page, and its sibling
memory_failure() receives pfn. This discrepancy looks weird and makes
precheck on pfn validity tricky. So let's align them.
Link: http://lkml.kernel.org/r/20191016234706.GA5493@www9186uo.sakura.ne.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_offline_node() is pretty much broken right now:
- The node span is updated when onlining memory, not when adding it. We
ignore memory that was mever onlined. Bad.
- We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily
trigger a kernel panic. Bad for memory that is offline but also bad
for subsection hotadd with ZONE_DEVICE, whereby the memmap of the
first PFN of a section might contain garbage.
- Sections belonging to mixed nodes are not properly considered.
As memory blocks might belong to multiple nodes, we would have to walk
all pageblocks (or at least subsections) within present sections.
However, we don't have a way to identify whether a memmap that is not
online was initialized (relevant for ZONE_DEVICE). This makes things
more complicated.
Luckily, we can piggy pack on the node span and the nid stored in memory
blocks. Currently, the node span is grown when calling
move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when
removing memory, before calling try_offline_node(). Sysfs links are
created via link_mem_sections(), e.g., during boot or when adding
memory.
If the node still spans memory or if any memory block belongs to the
nid, we don't set the node offline. As memory blocks that span multiple
nodes cannot get offlined, the nid stored in memory blocks is reliable
enough (for such online memory blocks, the node still spans the memory).
Introduce for_each_memory_block() to efficiently walk all memory blocks.
Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span
when removing ZONE_DEVICE memory to fix similar issues (access of
garbage memmaps) - until we have a reliable way to identify whether
these memmaps were properly initialized. This implies later, that once
a node had ZONE_DEVICE memory, we won't be able to set a node offline -
which should be acceptable.
Since commit f1dd2cd13c ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") memory that is added is not
assoziated with a zone/node (memmap not initialized). The introducing
commit 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
already missed that we could have multiple nodes for a section and that
the zone/node span is updated when onlining pages, not when adding them.
I tested this by hotplugging two DIMMs to a memory-less and cpu-less
NUMA node. The node is properly onlined when adding the DIMMs. When
removing the DIMMs, the node is properly offlined.
Masayoshi Mizuma reported:
: Without this patch, memory hotplug fails as panic:
:
: BUG: kernel NULL pointer dereference, address: 0000000000000000
: ...
: Call Trace:
: remove_memory_block_devices+0x81/0xc0
: try_remove_memory+0xb4/0x130
: __remove_memory+0xa/0x20
: acpi_memory_device_remove+0x84/0x100
: acpi_bus_trim+0x57/0x90
: acpi_bus_trim+0x2e/0x90
: acpi_device_hotplug+0x2b2/0x4d0
: acpi_hotplug_work_fn+0x1a/0x30
: process_one_work+0x171/0x380
: worker_thread+0x49/0x3f0
: kthread+0xf8/0x130
: ret_from_fork+0x35/0x40
[david@redhat.com: v3]
Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com
Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com
Fixes: 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Uninitialized memmaps contain garbage and in the worst case trigger kernel
BUGs, especially with CONFIG_PAGE_POISONING. They should not get touched.
Right now, when trying to soft-offline a PFN that resides on a memory
block that was never onlined, one gets a misleading error with
CONFIG_PAGE_POISONING:
:/# echo 5637144576 > /sys/devices/system/memory/soft_offline_page
[ 23.097167] soft offline: 0x150000 page already poisoned
But the actual result depends on the garbage in the memmap.
soft_offline_page() can only work with online pages, it returns -EIO in
case of ZONE_DEVICE. Make sure to only forward pages that are online
(iow, managed by the buddy) and, therefore, have an initialized memmap.
Add a check against pfn_to_online_page() and similarly return -EIO.
Link: http://lkml.kernel.org/r/20191010141200.8985-1-david@redhat.com
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b]
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: <stable@vger.kernel.org> [4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each memory block spans the same amount of sections/pages/bytes. The size
is determined before the first memory block is created. No need to store
what we can easily calculate - and the calculations even look simpler now.
Michal brought up the idea of variable-sized memory blocks. However, if
we ever implement something like this, we will need an API compatibility
switch and reworks at various places (most code assumes a fixed memory
block size). So let's cleanup what we have right now.
While at it, fix the variable naming in register_mem_sect_under_node() -
we no longer talk about a single section.
Link: http://lkml.kernel.org/r/20190809110200.2746-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's validate the memory block size early, when initializing the memory
device infrastructure. Fail hard in case the value is not suitable.
As nobody checks the return value of memory_dev_init(), turn it into a
void function and fail with a panic in all scenarios instead. Otherwise,
we'll crash later during boot when core/drivers expect that the memory
device infrastructure (including memory_block_size_bytes()) works as
expected.
I think long term, we should move the whole memory block size
configuration (set_memory_block_size_order() and
memory_block_size_bytes()) into drivers/base/memory.c.
Link: http://lkml.kernel.org/r/20190806090142.22709-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's rephrase to memory block terminology and add some further
clarifications.
Link: http://lkml.kernel.org/r/20190806080826.5963-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't allow to offline memory block devices that belong to multiple
numa nodes. Therefore, such devices can never get removed. It is
sufficient to process a single node when removing the memory block. No
need to iterate over each and every PFN.
We already have the nid stored for each memory block. Make sure that the
nid always has a sane value.
Please note that checking for node_online(nid) is not required. If we
would have a memory block belonging to a node that is no longer offline,
then we would have a BUG in the node offlining code.
Link: http://lkml.kernel.org/r/20190719135244.15242-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No longer needed, let's remove it. Also, drop the "hint" parameter
completely from "find_memory_block_by_id", as nobody needs it anymore.
[david@redhat.com: v3]
Link: http://lkml.kernel.org/r/20190620183139.4352-7-david@redhat.com
[david@redhat.com: handle zero-length walks]
Link: http://lkml.kernel.org/r/1c2edc22-afd7-2211-c4c7-40e54e5007e8@redhat.com
Link: http://lkml.kernel.org/r/20190614100114.311-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's move walk_memory_blocks() to the place where memory block logic
resides and simplify it. While at it, add a type for the callback
function.
Link: http://lkml.kernel.org/r/20190614100114.311-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Block ids are just shifted section numbers, so let's also use "unsigned
long" for them, too.
Link: http://lkml.kernel.org/r/20190614100114.311-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: Further memory block device cleanups", v1.
Some further cleanups around memory block devices. Especially, clean up
and simplify walk_memory_range(). Including some other minor cleanups.
This patch (of 6):
We are using a mixture of "int" and "unsigned long". Let's make this
consistent by using "unsigned long" everywhere. We'll do the same with
memory block ids next.
While at it, turn the "unsigned long i" in removable_show() into an int
- sections_per_block is an int.
[akpm@linux-foundation.org: s/unsigned long i/unsigned long nr/]
[david@redhat.com: v3]
Link: http://lkml.kernel.org/r/20190620183139.4352-2-david@redhat.com
Link: http://lkml.kernel.org/r/20190614100114.311-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's factor out removing of memory block devices, which is only
necessary for memory added via add_memory() and friends that created
memory block devices. Remove the devices before calling
arch_remove_memory().
This finishes factoring out memory block device handling from
arch_add_memory() and arch_remove_memory().
Link: http://lkml.kernel.org/r/20190527111152.16324-10-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jun Yao <yaojun8558363@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Only memory to be added to the buddy and to be onlined/offlined by user
space using /sys/devices/system/memory/... needs (and should have!)
memory block devices.
Factor out creation of memory block devices. Create all devices after
arch_add_memory() succeeded. We can later drop the want_memblock
parameter, because it is now effectively stale.
Only after memory block devices have been added, memory can be onlined
by user space. This implies, that memory is not visible to user space
at all before arch_add_memory() succeeded.
While at it
- use WARN_ON_ONCE instead of BUG_ON in moved unregister_memory()
- introduce find_memory_block_by_id() to search via block id
- Use find_memory_block_by_id() in init_memory_block() to catch
duplicates
Link: http://lkml.kernel.org/r/20190527111152.16324-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jun Yao <yaojun8558363@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want to improve error handling while adding memory by allowing to use
arch_remove_memory() and __remove_pages() even if
CONFIG_MEMORY_HOTREMOVE is not set to e.g., implement something like:
arch_add_memory()
rc = do_something();
if (rc) {
arch_remove_memory();
}
We won't get rid of CONFIG_MEMORY_HOTREMOVE for now, as it will require
quite some dependencies for memory offlining.
Link: http://lkml.kernel.org/r/20190527111152.16324-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jun Yao <yaojun8558363@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The input parameter 'phys_index' of memory_block_action() is actually the
section number, but not the phys_index of memory_block. This is a relic
from the past when one memory block could only contain one section.
Rename it to start_section_nr.
And also in remove_memory_section(), the 'node_id' and 'phys_device'
arguments are not used by anyone. Remove them.
Link: http://lkml.kernel.org/r/20190329144250.14315-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When adding memory by probing a memory block in the sysfs interface,
there is an obvious issue where we will unlock the device_hotplug_lock
when we failed to takes it.
That issue was introduced in 8df1d0e4a2 ("mm/memory_hotplug: make
add_memory() take the device_hotplug_lock").
We should drop out in time when failing to take the device_hotplug_lock.
Link: http://lkml.kernel.org/r/1554696437-9593-1-git-send-email-zhongjiang@huawei.com
Fixes: 8df1d0e4a2 ("mm/memory_hotplug: make add_memory() take the device_hotplug_lock")
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reported-by: Yang yingliang <yangyingliang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is intended for use with NVDIMMs that are physically persistent
(physically like flash) so that they can be used as a cost-effective
RAM replacement. Intel Optane DC persistent memory is one
implementation of this kind of NVDIMM.
Currently, a persistent memory region is "owned" by a device driver,
either the "Direct DAX" or "Filesystem DAX" drivers. These drivers
allow applications to explicitly use persistent memory, generally
by being modified to use special, new libraries. (DIMM-based
persistent memory hardware/software is described in great detail
here: Documentation/nvdimm/nvdimm.txt).
However, this limits persistent memory use to applications which
*have* been modified. To make it more broadly usable, this driver
"hotplugs" memory into the kernel, to be managed and used just like
normal RAM would be.
To make this work, management software must remove the device from
being controlled by the "Device DAX" infrastructure:
echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind
and then tell the new driver that it can bind to the device:
echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id
After this, there will be a number of new memory sections visible
in sysfs that can be onlined, or that may get onlined by existing
udev-initiated memory hotplug rules.
This rebinding procedure is currently a one-way trip. Once memory
is bound to "kmem", it's there permanently and can not be
unbound and assigned back to device_dax.
The kmem driver will never bind to a dax device unless the device
is *explicitly* bound to the driver. There are two reasons for
this: One, since it is a one-way trip, it can not be undone if
bound incorrectly. Two, the kmem driver destroys data on the
device. Think of if you had good data on a pmem device. It
would be catastrophic if you compile-in "kmem", but leave out
the "device_dax" driver. kmem would take over the device and
write volatile data all over your good data.
This inherits any existing NUMA information for the newly-added
memory from the persistent memory device that came from the
firmware. On Intel platforms, the firmware has guarantees that
require each socket's persistent memory to be in a separate
memory-only NUMA node. That means that this patch is not expected
to create NUMA nodes, but will simply hotplug memory into existing
nodes.
Because NUMA nodes are created, the existing NUMA APIs and tools
are sufficient to create policies for applications or memory areas
to have affinity for or an aversion to using this memory.
There is currently some metadata at the beginning of pmem regions.
The section-size memory hotplug restrictions, plus this small
reserved area can cause the "loss" of a section or two of capacity.
This should be fixable in follow-on patches. But, as a first step,
losing 256MB of memory (worst case) out of hundreds of gigabytes
is a good tradeoff vs. the required code to fix this up precisely.
This calculation is also the reason we export
memory_block_size_bytes().
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-nvdimm@lists.01.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Huang Ying <ying.huang@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Here is the "big" set of driver core patches for 4.21-rc1.
It's not really big, just a number of small changes for some reported
issues, some documentation updates to hopefully make it harder for
people to abuse the driver model, and some other minor cleanups.
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCXCY/dA8cZ3JlZ0Brcm9h
aC5jb20ACgkQMUfUDdst+ylZrgCeIi+rWj0mqlyKZk0A+gurH2BPmfwAniGfiHJp
w60Fr5/EbCqUr1d1wQIO
=4N7R
-----END PGP SIGNATURE-----
Merge tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the "big" set of driver core patches for 4.21-rc1.
It's not really big, just a number of small changes for some reported
issues, some documentation updates to hopefully make it harder for
people to abuse the driver model, and some other minor cleanups.
All of these have been in linux-next for a while with no reported
issues"
* tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
mm, memory_hotplug: update a comment in unregister_memory()
component: convert to DEFINE_SHOW_ATTRIBUTE
sysfs: Disable lockdep for driver bind/unbind files
driver core: Add missing dev->bus->need_parent_lock checks
kobject: return error code if writing /sys/.../uevent fails
driver core: Move async_synchronize_full call
driver core: platform: Respect return code of platform_device_register_full()
kref/kobject: Improve documentation
drivers/base/memory.c: Use DEVICE_ATTR_RO and friends
driver core: Replace simple_strto{l,ul} by kstrtou{l,ul}
kernfs: Improve kernfs_notify() poll notification latency
kobject: Fix warnings in lib/kobject_uevent.c
kobject: drop unnecessary cast "%llu" for u64
driver core: fix comments for device_block_probing()
driver core: Replace simple_strtol by kstrtoint
pages_correctly_probed is missing new lines which means that the line is
not printed rightaway but it rather waits for additional printks.
Add \n to all three messages in pages_correctly_probed.
Link: http://lkml.kernel.org/r/20181218162307.10518-1-mhocko@kernel.org
Fixes: b77eab7079 ("mm/memory_hotplug: optimize probe routine")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In cb5e39b803 ("drivers: base: refactor add_memory_section() to
add_memory_block()"), add_memory_block() is introduced, which is only
invoked in memory_dev_init().
When combining these two loops in memory_dev_init() and
add_memory_block(), they looks like this:
for (i = 0; i < NR_MEM_SECTIONS; i += sections_per_block)
for (j = i;
(j < i + sections_per_block) && j < NR_MEM_SECTIONS;
j++)
Since it is sure the (i < NR_MEM_SECTIONS) and j sits in its own memory
block, the check of (j < NR_MEM_SECTIONS) is not necessary.
This patch just removes this check.
Link: http://lkml.kernel.org/r/20181123222811.18216-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The remove_memory_block() function was renamed to in commit
cc292b0b43 ("drivers/base/memory.c: rename remove_memory_block() to
remove_memory_section()").
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Let's use the easier to read (and not mess up) variants:
- Use DEVICE_ATTR_RO
- Use DEVICE_ATTR_WO
- Use DEVICE_ATTR_RW
instead of the more generic DEVICE_ATTR() we're using right now.
We have to rename most callback functions. By fixing the intendations we
can even save some LOCs.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There seem to be some problems as result of 30467e0b3b ("mm, hotplug:
fix concurrent memory hot-add deadlock"), which tried to fix a possible
lock inversion reported and discussed in [1] due to the two locks
a) device_lock()
b) mem_hotplug_lock
While add_memory() first takes b), followed by a) during
bus_probe_device(), onlining of memory from user space first took a),
followed by b), exposing a possible deadlock.
In [1], and it was decided to not make use of device_hotplug_lock, but
rather to enforce a locking order.
The problems I spotted related to this:
1. Memory block device attributes: While .state first calls
mem_hotplug_begin() and the calls device_online() - which takes
device_lock() - .online does no longer call mem_hotplug_begin(), so
effectively calls online_pages() without mem_hotplug_lock.
2. device_online() should be called under device_hotplug_lock, however
onlining memory during add_memory() does not take care of that.
In addition, I think there is also something wrong about the locking in
3. arch/powerpc/platforms/powernv/memtrace.c calls offline_pages()
without locks. This was introduced after 30467e0b3b. And skimming over
the code, I assume it could need some more care in regards to locking
(e.g. device_online() called without device_hotplug_lock. This will
be addressed in the following patches.
Now that we hold the device_hotplug_lock when
- adding memory (e.g. via add_memory()/add_memory_resource())
- removing memory (e.g. via remove_memory())
- device_online()/device_offline()
We can move mem_hotplug_lock usage back into
online_pages()/offline_pages().
Why is mem_hotplug_lock still needed? Essentially to make
get_online_mems()/put_online_mems() be very fast (relying on
device_hotplug_lock would be very slow), and to serialize against
addition of memory that does not create memory block devices (hmm).
[1] http://driverdev.linuxdriverproject.org/pipermail/ driverdev-devel/
2015-February/065324.html
This patch is partly based on a patch by Vitaly Kuznetsov.
Link: http://lkml.kernel.org/r/20180925091457.28651-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.
In general, we should hold the device_hotplug_lock when adding memory to
synchronize against online/offline request (e.g. from user space) - which
already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3b ("mm, hotplug: fix concurrent memory
hot-add deadlock"). add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.
Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.
The lock is not held yet in
drivers/xen/balloon.c
arch/powerpc/platforms/powernv/memtrace.c
drivers/s390/char/sclp_cmd.c
drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.
Don't export add_memory_resource(), as it once was exported to be used by
XEN, which is never built as a module. If somebody requires it, we also
have to export a locked variant (as device_hotplug_lock is never
exported).
Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Within show_valid_zones() the function test_pages_in_a_zone() should be
called for online memory blocks only.
Otherwise it might lead to the VM_BUG_ON due to uninitialized struct
pages (when CONFIG_DEBUG_VM_PGFLAGS kernel option is set):
page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
------------[ cut here ]------------
Call Trace:
([<000000000038f91e>] test_pages_in_a_zone+0xe6/0x168)
[<0000000000923472>] show_valid_zones+0x5a/0x1a8
[<0000000000900284>] dev_attr_show+0x3c/0x78
[<000000000046f6f0>] sysfs_kf_seq_show+0xd0/0x150
[<00000000003ef662>] seq_read+0x212/0x4b8
[<00000000003bf202>] __vfs_read+0x3a/0x178
[<00000000003bf3ca>] vfs_read+0x8a/0x148
[<00000000003bfa3a>] ksys_read+0x62/0xb8
[<0000000000bc2220>] system_call+0xdc/0x2d8
That VM_BUG_ON was triggered by the page poisoning introduced in
mm/sparse.c with the git commit d0dc12e86b ("mm/memory_hotplug:
optimize memory hotplug").
With the same commit the new 'nid' field has been added to the struct
memory_block in order to store and later on derive the node id for
offline pages (instead of accessing struct page which might be
uninitialized). But one reference to nid in show_valid_zones() function
has been overlooked. Fixed with current commit. Also, nr_pages will
not be used any more after test_pages_in_a_zone() call, do not update
it.
Link: http://lkml.kernel.org/r/20180828090539.41491-1-zaslonko@linux.ibm.com
Fixes: d0dc12e86b ("mm/memory_hotplug: optimize memory hotplug")
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: <stable@vger.kernel.org> [4.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When hotplugging memory, it is possible that two calls are being made to
register_mem_sect_under_node().
One comes from __add_section()->hotplug_memory_register() and the other
from add_memory_resource()->link_mem_sections() if we had to register a
new node.
In case we had to register a new node, hotplug_memory_register() will
only handle/allocate the memory_block's since
register_mem_sect_under_node() will return right away because the node
it is not online yet.
I think it is better if we leave hotplug_memory_register() to
handle/allocate only memory_block's and make link_mem_sections() to call
register_mem_sect_under_node().
So this patch removes the call to register_mem_sect_under_node() from
hotplug_memory_register(), and moves the call to link_mem_sections() out
of the condition, so it will always be called. In this way we only have
one place where the memory sections are registered.
Link: http://lkml.kernel.org/r/20180622111839.10071-3-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
if device_register() returned an error. Always use put_device()
to give up the initialized reference and release allocated memory.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
__highest_present_section_nr is a more strict boundary than
NR_MEM_SECTIONS. So checking __highest_present_section_nr directly is
enough.
Link: http://lkml.kernel.org/r/20180330032044.21647-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During memory hotplugging the probe routine will leave struct pages
uninitialized, the same as it is currently done during boot. Therefore,
we do not want to access the inside of struct pages before
__init_single_page() is called during onlining.
Because during hotplug we know that pages in one memory block belong to
the same numa node, we can skip the checking. We should keep checking
for the boot case.
[pasha.tatashin@oracle.com: s/register_new_memory()/hotplug_memory_register()]
Link: http://lkml.kernel.org/r/20180228030308.1116-6-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180215165920.8570-6-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory is hotplugged pages_correctly_reserved() is called to verify
that the added memory is present, this routine traverses through every
struct page and verifies that PageReserved() is set. This is a slow
operation especially if a large amount of memory is added.
Instead of checking every page, it is enough to simply check that the
section is present, has mapping (struct page array is allocated), and
the mapping is online.
In addition, we should not excpect that probe routine sets flags in
struct page, as the struct pages have not yet been initialized. The
initialization should be done in __init_single_page(), the same as
during boot.
Link: http://lkml.kernel.org/r/20180215165920.8570-5-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Today 4 architectures set ARCH_SUPPORTS_MEMORY_FAILURE (arm64, parisc,
powerpc, and x86), while 4 other architectures set __ARCH_SI_TRAPNO
(alpha, metag, sparc, and tile). These two sets of architectures do
not interesect so remove the trapno paramater to remove confusion.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Historically we have enforced that any kernel zone (e.g ZONE_NORMAL) has
to precede the Movable zone in the physical memory range. The purpose
of the movable zone is, however, not bound to any physical memory
restriction. It merely defines a class of migrateable and reclaimable
memory.
There are users (e.g. CMA) who might want to reserve specific physical
memory ranges for their own purpose. Moreover our pfn walkers have to
be prepared for zones overlapping in the physical range already because
we do support interleaving NUMA nodes and therefore zones can interleave
as well. This means we can allow each memory block to be associated
with a different zone.
Loosen the current onlining semantic and allow explicit onlining type on
any memblock. That means that online_{kernel,movable} will be allowed
regardless of the physical address of the memblock as long as it is
offline of course. This might result in moveble zone overlapping with
other kernel zones. Default onlining then becomes a bit tricky but
still sensible. echo online > memoryXY/state will online the given
block to
1) the default zone if the given range is outside of any zone
2) the enclosing zone if such a zone doesn't interleave with
any other zone
3) the default zone if more zones interleave for this range
where default zone is movable zone only if movable_node is enabled
otherwise it is a kernel zone.
Here is an example of the semantic with (movable_node is not present but
it work in an analogous way). We start with following memblocks, all of
them offline:
memory34/valid_zones:Normal Movable
memory35/valid_zones:Normal Movable
memory36/valid_zones:Normal Movable
memory37/valid_zones:Normal Movable
memory38/valid_zones:Normal Movable
memory39/valid_zones:Normal Movable
memory40/valid_zones:Normal Movable
memory41/valid_zones:Normal Movable
Now, we online block 34 in default mode and block 37 as movable
root@test1:/sys/devices/system/node/node1# echo online > memory34/state
root@test1:/sys/devices/system/node/node1# echo online_movable > memory37/state
memory34/valid_zones:Normal
memory35/valid_zones:Normal Movable
memory36/valid_zones:Normal Movable
memory37/valid_zones:Movable
memory38/valid_zones:Normal Movable
memory39/valid_zones:Normal Movable
memory40/valid_zones:Normal Movable
memory41/valid_zones:Normal Movable
As we can see all other blocks can still be onlined both into Normal and
Movable zones and the Normal is default because the Movable zone spans
only block37 now.
root@test1:/sys/devices/system/node/node1# echo online_movable > memory41/state
memory34/valid_zones:Normal
memory35/valid_zones:Normal Movable
memory36/valid_zones:Normal Movable
memory37/valid_zones:Movable
memory38/valid_zones:Movable Normal
memory39/valid_zones:Movable Normal
memory40/valid_zones:Movable Normal
memory41/valid_zones:Movable
Now the default zone for blocks 37-41 has changed because movable zone
spans that range.
root@test1:/sys/devices/system/node/node1# echo online_kernel > memory39/state
memory34/valid_zones:Normal
memory35/valid_zones:Normal Movable
memory36/valid_zones:Normal Movable
memory37/valid_zones:Movable
memory38/valid_zones:Normal Movable
memory39/valid_zones:Normal
memory40/valid_zones:Movable Normal
memory41/valid_zones:Movable
Note that the block 39 now belongs to the zone Normal and so block38
falls into Normal by default as well.
For completness
root@test1:/sys/devices/system/node/node1# for i in memory[34]?
do
echo online > $i/state 2>/dev/null
done
memory34/valid_zones:Normal
memory35/valid_zones:Normal
memory36/valid_zones:Normal
memory37/valid_zones:Movable
memory38/valid_zones:Normal
memory39/valid_zones:Normal
memory40/valid_zones:Movable
memory41/valid_zones:Movable
Implementation wise the change is quite straightforward. We can get rid
of allow_online_pfn_range altogether. online_pages allows only offline
nodes already. The original default_zone_for_pfn will become
default_kernel_zone_for_pfn. New default_zone_for_pfn implements the
above semantic. zone_for_pfn_range is slightly reorganized to implement
kernel and movable online type explicitly and MMOP_ONLINE_KEEP becomes a
catch all default behavior.
Link: http://lkml.kernel.org/r/20170714121233.16861-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: <slaoub@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prior to commit f1dd2cd13c ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") we used to allow to change the
valid zone types of a memory block if it is adjacent to a different zone
type.
This fact was reflected in memoryNN/valid_zones by the ordering of
printed zones. The first one was default (echo online > memoryNN/state)
and the other one could be onlined explicitly by online_{movable,kernel}.
This behavior was removed by the said patch and as such the ordering was
not all that important. In most cases a kernel zone would be default
anyway. The only exception is movable_node handled by "mm,
memory_hotplug: support movable_node for hotpluggable nodes".
Let's reintroduce this behavior again because later patch will remove
the zone overlap restriction and so user will be allowed to online
kernel resp. movable block regardless of its placement. Original
behavior will then become significant again because it would be
non-trivial for users to see what is the default zone to online into.
Implementation is really simple. Pull out zone selection out of
move_pfn_range into zone_for_pfn_range helper and use it in
show_valid_zones to display the zone for default onlining and then both
kernel and movable if they are allowed. Default online zone is not
duplicated.
Link: http://lkml.kernel.org/r/20170714121233.16861-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: <slaoub@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens has noticed that he can generate overlapping zones for
ZONE_DMA and ZONE_NORMAL:
DMA [mem 0x0000000000000000-0x000000007fffffff]
Normal [mem 0x0000000080000000-0x000000017fffffff]
$ cat /sys/devices/system/memory/block_size_bytes
10000000
$ cat /sys/devices/system/memory/memory5/valid_zones
DMA
$ echo 0 > /sys/devices/system/memory/memory5/online
$ cat /sys/devices/system/memory/memory5/valid_zones
Normal
$ echo 1 > /sys/devices/system/memory/memory5/online
Normal
$ cat /proc/zoneinfo
Node 0, zone DMA
spanned 524288 <-----
present 458752
managed 455078
start_pfn: 0 <-----
Node 0, zone Normal
spanned 720896
present 589824
managed 571648
start_pfn: 327680 <-----
The reason is that we assume that the default zone for kernel onlining
is ZONE_NORMAL. This was a simplification introduced by the memory
hotplug rework and it is easily fixable by checking the range overlap in
the zone order and considering the first matching zone as the default
one. If there is no such zone then assume ZONE_NORMAL as we have been
doing so far.
Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online"
Link: http://lkml.kernel.org/r/20170601083746.4924-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Scott Cheloha