Reading the CMOS clock on x86 and some other arches currently takes up to one
second because it synchronizes with the CMOS second tick-over. This delay
shows up at boot time as well a resume time.
This is the currently the most substantial boot time delay for machines that
are working towards instant-on capability. Also, a quick back of the envelope
calculation (.5sec * 2M users * 1 boot a day * 10 years) suggests it has cost
Linux users in the neighborhood of a million man-hours.
An earlier thread on this topic is here:
http://groups.google.com/group/linux.kernel/browse_frm/thread/8a24255215ff6151/2aa97e66a977653d?hl=en&lr=&ie=UTF-8&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D1To2R-2S7-11%40gated-at.bofh.it#2aa97e66a977653d
..from which the consensus seems to be that it's no longer desirable.
In my view, there are basically four cases to consider:
1) networked, need precise walltime: use NTP
2) networked, don't need precise walltime: use NTP anyway
3) not networked, don't need sub-second precision walltime: don't care
4) not networked, need sub-second precision walltime:
get a network or a radio time source because RTC isn't good enough anyway
So this patch series simply removes the synchronization in favor of a simple
seqlock-like approach using the seconds value.
Note that for purposes of timer accuracy on wakeup, this patch will cause us
to fire timers up to one second late. But as the current timer resume code
will already sync once (or more!), it's no worse for short timers.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This removes statically assigned platform numbers and reworks the
powerpc platform probe code to use a better mechanism. With this,
board support files can simply declare a new machine type with a
macro, and implement a probe() function that uses the flattened
device-tree to detect if they apply for a given machine.
We now have a machine_is() macro that replaces the comparisons of
_machine with the various PLATFORM_* constants. This commit also
changes various drivers to use the new macro instead of looking at
_machine.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Now that the strncasecmp implementation takes a size_t third parameter,
we need to get a definition of size_t from somewhere.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Detect whether a given process is seeky and if so disable (mostly) the
idle window if it is. We still allow just a little idle time, just enough
to allow that process to submit a new request. That is needed to maintain
fairness across priority groups.
In some cases, we could setup several async queues. This is not optimal
from a performance POV, since we want all async io in one queue to perform
good sorting on it. It also impacted sync queues, as async io got too much
slice time.
Signed-off-by: Jens Axboe <axboe@suse.de>
There are at least 14 different implementations of WARN() in the tree already.
The build fails all over the place.
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
As per the corresponding change to the serial drivers, arrange
for ARM decompressors to give CRLF. Move the common putstr code
into misc.c such that machines only need to supply "putc" and
"flush" functions.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
this is a small optimization to cfq_choose_req() in the CFQ I/O scheduler
(this function is a semi-often invoked candidate in an oprofile log):
by using a bit mask variable, we can use a simple switch() to check
the various cases instead of having to query two variables for each check.
Benefit: 251 vs. 285 bytes footprint of cfq_choose_req().
Also, common case 0 (no request wrapping) is now checked first in code.
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Jens Axboe <axboe@suse.de>
On setups with many disks, we spend a considerable amount of time
looking up the process-disk mapping on each queue of io. Testing with
a NULL based block driver, this costs 40-50% reduction in throughput
for 1000 disks.
Signed-off-by: Jens Axboe <axboe@suse.de>
We used to assume that a DMA mapping request with a NULL dev was for
ISA DMA. This assumption was broken at some point. Now we explicitly
pass the detected ISA PCI device in the floppy setup.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Non zero initcalls (except for -ENODEV) have started warning at boot.
Fix smt_setup and init_ras_IRQ.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
A bug in the RTAS services incorrectly interprets some bits in the CR
when called from the OS. Specifically, bits in CR4. The result could
be a firmware crash that also takes down the partition. A firmware
fix is in the works. We have seen this situation when performing DLPAR
operations. As a temporary workaround, clear the CR in enter_rtas().
Note that enter_rtas() will not set any bits in CR4 before calling RTAS.
Also note that the 32 bit version of enter_rtas() should have the same
work around even though the chances of hitting the bug are much smaller
due to the lack of DLPAR on 32 bit kernels. However, my assembly skills
are a bit rusty and the 32 bit code doesn't seem to follow the conventions
for where things should be saved. In addition, I don't have a system
to test 32 bit kernels. Help creating and at least touch testing the
same workaround for 32 bit would be appreciated.
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
spufs_init and spufs_exit should be marked correctly so
they can be removed when not needed.
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Current Cell hardware is using the console through a set
of rtas calls. This driver is needed to get console
output on those boards.
Signed-off-by: Arnd Bergmann <abergman@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
These are some updates from both Ryan and Arnd for the hvc_console
driver:
The main point is to enable the inclusion of a console driver
for rtas, which is currrently needed for the cell platform.
Also shuffle around some data-type declarations and moves some
functions out of include/asm-ppc64/hvconsole.h and into a new
drivers/char/hvc_console.h file.
Signed-off-by: "Ryan S. Arnold" <rsa@us.ibm.com>
Signed-off-by: Arnd Bergmann <abergman@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
*) When setting a sighandler using sigaction() call, if the flag
SA_ONSTACK is set and no alternate stack is provided via sigaltstack(),
the kernel still try to install the alternate stack. This behavior is
the opposite of the one which is documented in Single Unix
Specifications V3.
*) Also when setting an alternate stack using sigaltstack() with the
flag SS_DISABLE, the kernel try to install the alternate stack on
signal delivery.
These two use cases makes the process crash at signal delivery.
This fixes it.
Signed-off-by: Laurent Meyer <meyerlau@fr.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Various dodgy firmware might give us nodes and/or properties in the device
tree with conflicting names. That's generally ok, except for when we export
the device tree via /proc, so check when we're creating the proc device tree
and munge names accordingly.
Tested on a faked device tree with kexec, would be good if someone with
actual bogus firmware could try it, but just for completeness.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We need to export ppc64_firmware_features for modules. Before we do that
I think we should probably rename it to powerpc_firmware_features.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
When we build for the MPC8540 ADS produce a uImage by default.
Updated the defconfig to reflect this as well.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Towards the goal of having arch/powerpc not build anything over in arch/ppc
move math-emu over. Also, killed some references to arch/ppc/ in the
arch/powerpc Makefile which should belong in drivers/ when the particular
sub-arch's move over to arch/powerpc.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Export validate_sp so we can use it in the oprofile calltrace code.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
- No one uses op_counter_config.valid, so remove it
- No need to ifdef around function protypes.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Match, Linus's fix to arch/powerpc in arch/ppc. strcasecmp takes a size_t,
not an int, as its third argument.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
32-bit CHRP machines are now supported only in arch/powerpc, as are
all 64-bit PowerPC processors. This means that we don't use
Open Firmware on any platform in arch/ppc any more.
This makes PReP support a single-platform option like every other
platform support option in arch/ppc now, thus CONFIG_PPC_MULTIPLATFORM
is gone from arch/ppc. CONFIG_PPC_PREP is the option that selects
PReP support and is generally what has replaced
CONFIG_PPC_MULTIPLATFORM within arch/ppc.
_machine is all but dead now, being #defined to 0.
Updated Makefiles, comments and Kconfig options generally to reflect
these changes.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This fixes a mistake I made when editing these functions - when I
took out the interrupt disabling code (because interrupts are now
disabled by the caller) I left the register that is used for the MSR
value to be used during doze/nap uninitialized. This fixes it.
Also updated some of the comments in idle_power4.S and removed some
code that was copied over from idle_6xx.S but is no longer relevant
(we don't ever clear the CPU_FTR_CAN_NAP bit at runtime for POWER4).
Signed-off-by: Paul Mackerras <paulus@samba.org>
Andi's previous fix to initialise powernow_data on all siblings
will not work properly with CPU Hotplug.
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
[NET]: drop duplicate assignment in request_sock
[IPSEC]: Fix tunnel error handling in ipcomp6
* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block:
[PATCH] Don't make debugfs depend on DEBUG_KERNEL
[PATCH] Fix blktrace compile with sysfs not defined
[PATCH] unused label in drivers/block/cciss.
[BLOCK] increase size of disk stat counters
[PATCH] blk_execute_rq_nowait-speedup
[PATCH] ide-cd: quiet down GPCMD_READ_CDVD_CAPACITY failure
[BLOCK] ll_rw_blk: kmalloc -> kzalloc conversion
[PATCH] kzalloc() conversion in drivers/block
[PATCH] update max_sectors documentation
... being careful that mutex_trylock is inverted wrt down_trylock
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When retrying a write due to barrier failure, we don't reset 'remaining', so
it goes negative and never hits 0 again.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
An md array can be asked to change the amount of each device that it is using,
and in particular can be asked to use the maximum available space. This
currently only works if the first device is not larger than the rest. As
'size' gets changed and so 'fit' becomes wrong. So check if a 'fit' is
required early and don't corrupt it.
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
raid5 overloads bi_phys_segments to count the number of blocks that the
request was broken in to so that it knows when the bio is completely handled.
Accessing this must always be done under a spinlock. In one case we also call
bi_end_io under that spinlock, which probably isn't ideal as bi_end_io could
be expensive (even though it isn't allowed to sleep).
So we reducde the range of the spinlock to just accessing bi_phys_segments.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
wait_event_lock_irq puts a ';' after its usage of the 4th arg, so we don't
need to.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This allows user-space to access data safely. This is needed for raid5
reshape as user-space needs to take a backup of the first few stripes before
allowing reshape to commence.
It will also be useful in cluster-aware raid1 configurations so that all
cluster members can leave a section of the array untouched while a
resync/recovery happens.
A 'start' and 'end' of the suspended range are written to 2 sysfs attributes.
Note that only one range can be suspended at a time.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This allows reshape to be triggerred via sysfs (which is the only way to start
it happening).
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Matt Mackall