The previous patches added the use of print_fmt string and changes
the trace_define_field() function to also create the fields and
format output for the event format files.
text data bss dec hex filename
5857201 1355780 9336808 16549789 fc879d vmlinux
5884589 1351684 9337896 16574169 fce6d9 vmlinux-orig
The above shows the size of the vmlinux after this patch set
compared to the vmlinux-orig which is before the patch set.
This saves us 27k on text, 1k on bss and adds just 4k of data.
The total savings of 24k in size.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D4D.40604@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the clean up of having all events call one specific function,
the syscall event init was changed to call this helper function.
With the new print_fmt updates, the syscalls need to do special
initializations. This patch converts the syscall events to call
its own init function again.
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The struct syscall_metadata variable name in SYSCALL_DEFINE0
should be __syscall_meta__##sname instead of __syscall_meta_##sname
to match the name that is in SYSCALL_DEFINE1/2/3/4/5/6.
This error causes event_enter_##sname->data to point to the wrong
location, which causes syscalls which are defined by SYSCALL_DEFINE0()
not to be traced.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D2E.1010807@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Quoted from Ingo:
| This reminds me - i think we should eliminate CONFIG_EVENT_PROFILE -
| it's an unnecessary Kconfig complication. If both PERF_EVENTS and
| EVENT_TRACING is enabled we should expose generic tracepoints.
|
| Nor is it limited to event 'profiling', so it has become a misnomer as
| well.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B2F1557.2050705@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Like total_profile_count, struct ftrace_event_call::profile_count
is protected by event_mutex, so it doesn't need to be atomic_t.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4B1DC549.5010705@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Use a generic trace_event_raw_init() function for all event's raw_init
callbacks (but kprobes) instead of defining the same version for each
of these.
This shrinks the kernel code:
text data bss dec hex filename
5355293 1961928 7103260 14420481 dc0a01 vmlinux.o.old
5346802 1961864 7103260 14411926 dbe896 vmlinux.o
raw_init can't be removed, because ftrace events and kprobe events
use different raw_init callbacks. Though it's possible to totally
remove raw_init, I choose to leave it as it is for now.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <4B1DC48C.7080603@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
New helper - sys_mmap_pgoff(); switch syscalls to using it.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1815 commits)
mac80211: fix reorder buffer release
iwmc3200wifi: Enable wimax core through module parameter
iwmc3200wifi: Add wifi-wimax coexistence mode as a module parameter
iwmc3200wifi: Coex table command does not expect a response
iwmc3200wifi: Update wiwi priority table
iwlwifi: driver version track kernel version
iwlwifi: indicate uCode type when fail dump error/event log
iwl3945: remove duplicated event logging code
b43: fix two warnings
ipw2100: fix rebooting hang with driver loaded
cfg80211: indent regulatory messages with spaces
iwmc3200wifi: fix NULL pointer dereference in pmkid update
mac80211: Fix TX status reporting for injected data frames
ath9k: enable 2GHz band only if the device supports it
airo: Fix integer overflow warning
rt2x00: Fix padding bug on L2PAD devices.
WE: Fix set events not propagated
b43legacy: avoid PPC fault during resume
b43: avoid PPC fault during resume
tcp: fix a timewait refcnt race
...
Fix up conflicts due to sysctl cleanups (dead sysctl_check code and
CTL_UNNUMBERED removed) in
kernel/sysctl_check.c
net/ipv4/sysctl_net_ipv4.c
net/ipv6/addrconf.c
net/sctp/sysctl.c
enter_syscall_print_##sname and exit_syscall_print_##sname don't
need to have a global scope. Make them static.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1259734990-9034-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
use only one prof_sysenter_enable() instead of
prof_sysenter_enable_##sname()
use only one prof_sysenter_disable() instead of
prof_sysenter_disable_##sname()
use only one prof_sysexit_enable() instead of
prof_sysexit_enable_##sname()
use only one prof_sysexit_disable() instead of
prof_sysexit_disable_##sname()
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D2A1.8060304@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
use only one init_syscall_trace instead of
many init_enter_##sname()/init_exit_##sname()
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D29B.6090708@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add syscall_nr field to struct syscall_metadata,
it helps us to get syscall number easier.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D293.6090800@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
use ->enter_event->id instead of ->enter_id
use ->exit_event->id instead of ->exit_id
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D288.7030001@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Set event_enter_##sname->data to its metadata,
it makes codes simpler.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14D282.7050709@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Meaning receive multiple messages, reducing the number of syscalls and
net stack entry/exit operations.
Next patches will introduce mechanisms where protocols that want to
optimize this operation will provide an unlocked_recvmsg operation.
This takes into account comments made by:
. Paul Moore: sock_recvmsg is called only for the first datagram,
sock_recvmsg_nosec is used for the rest.
. Caitlin Bestler: recvmmsg now has a struct timespec timeout, that
works in the same fashion as the ppoll one.
If the underlying protocol returns a datagram with MSG_OOB set, this
will make recvmmsg return right away with as many datagrams (+ the OOB
one) it has received so far.
. Rémi Denis-Courmont & Steven Whitehouse: If we receive N < vlen
datagrams and then recvmsg returns an error, recvmmsg will return
the successfully received datagrams, store the error and return it
in the next call.
This paves the way for a subsequent optimization, sk_prot->unlocked_recvmsg,
where we will be able to acquire the lock only at batch start and end, not at
every underlying recvmsg call.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For this system call user space passes a signed long length parameter,
while the kernel side takes an unsigned long parameter and converts it
later to signed long again.
This has led to bugs in compat wrappers see e.g. dd90bbd5 "powerpc: Add
compat_sys_truncate". The s390 compat wrapper for this functions is
broken as well since it also performs zero extension instead of sign
extension for the length parameter.
In addition if hpa comes up with an automated way of generating
compat wrappers it would generate a wrong one here.
So change the length parameter from unsigned long to long.
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'perfcounters-rename-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: Tidy up after the big rename
perf: Do the big rename: Performance Counters -> Performance Events
perf_counter: Rename 'event' to event_id/hw_event
perf_counter: Rename list_entry -> group_entry, counter_list -> group_list
Manually resolved some fairly trivial conflicts with the tracing tree in
include/trace/ftrace.h and kernel/trace/trace_syscalls.c.
Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.
Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.
All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)
The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.
Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.
User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)
This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILES
for N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
done
FILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\<event\>/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES
... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.
Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.
( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Factorize the events enabling accounting in a common tracing core
helper. This reduces the size of the profile_enable() and
profile_disable() callbacks for each trace events.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Conflicts:
kernel/trace/trace_export.c
kernel/trace/trace_kprobe.c
Merge reason: This topic branch lacks an important
build fix in tracing/core:
0dd7b74787eaf7858c6c573353a83c3e2766e674:
tracing: Fix double CPP substitution in TRACE_EVENT_FN
that prevents from multiple tracepoint headers inclusion crashes.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
init_preds() allocates about 5392 bytes of memory (on x86_32) for
a TRACE_EVENT. With my config, at system boot total memory occupied
is:
5392 * (642 + 15) == 3459KB
642 == cat available_events | wc -l
15 == number of dirs in events/ftrace
That's quite a lot, so we'd better defer memory allocation util
it's needed, that's when filter is used.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add dynamic ftrace_event_call support to ftrace. Trace engines can add
new ftrace_event_call to ftrace on the fly. Each operator function of
the call takes an ftrace_event_call data structure as an argument,
because these functions may be shared among several ftrace_event_calls.
Changes from v13:
- Define remove_subsystem_dir() always (revirt a2ca5e03), because
trace_remove_event_call() uses it.
- Modify syscall tracer because of ftrace_event_call change.
[fweisbec@gmail.com: Fixed conflict against latest tracing/core]
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203453.31965.71901.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Define the format of the syscall trace fields to parse the binary
values from a raw trace using the syscall events "format" file.
This is defined dynamically using the syscalls metadata.
It prepares the export of syscall event raw records to perf
counters.
Example:
$ cat /debug/tracing/events/syscalls/sys_enter_sched_getparam/format
name: sys_enter_sched_getparam
ID: 39
format:
field:unsigned short common_type; offset:0; size:2;
field:unsigned char common_flags; offset:2; size:1;
field:unsigned char common_preempt_count; offset:3; size:1;
field:int common_pid; offset:4; size:4;
field:int common_tgid; offset:8; size:4;
field:pid_t pid; offset:12; size:8;
field:struct sched_param * param; offset:20; size:8;
print fmt: "pid: 0x%08lx, param: 0x%08lx", ((unsigned long)(REC->pid)), ((unsigned long)(REC->param))
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
The perf counter support is automated for usual trace events. But we
have to define specific callbacks for this to handle syscalls trace
events
Make 'perf stat -e syscalls:sys_enter_blah' work with syscall style
tracepoints.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
The current state of syscalls tracepoints generates only one event id
for every syscall events.
This patch associates an id with each syscall trace event, so that we
can identify each syscall trace event using the 'perf' tool.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Layer Frederic's syscall tracer on tracepoints. We create trace events
via hooking into the SYSCALL_DEFINE macros. This allows us to
individually toggle syscall entry and exit points on/off.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
sys_rt_tgsigqueueinfo needs to be declared in linux/syscalls.h so that
architectures defining the system call table in C can reference it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <200907071023.44008.arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Provide for means of extending the perf_counter_attr in a 'natural' way.
We allow growing the structure by appending fields at the end by specifying
the full structure size inside it.
When a new kernel sees a smaller (old) structure, it will 0 pad the tail.
When an old kernel sees a larger (new) structure, it will verify the tail
consists of 0s, otherwise fail.
If we fail due to a size-mismatch, we return -E2BIG and write the kernel's
native attribe size back into the provided structure.
Furthermore, add some attribute verification, so that we'll fail counter
creation when unknown bits are present (PERF_SAMPLE, PERF_FORMAT, or in
the __reserved fields).
(This ABI detail is introduced while keeping the existing syscall ABI.)
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The structure isn't hw only and when I read event, I think about those
things that fall out the other end. Rename the thing.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
Cc: Stephane Eranian <eranian@googlemail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In order to build the generic syscall table, we need a declaration for
every system call. sys_pipe2 was added without a proper declaration, so
add this to syscalls.h now.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Older MIPS assembler don't support .set for defining aliases.
Using = works for old and new assembers.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix build warnings and possibe compat misbehavior on IA64
Building a kernel on ia64 might trigger these ugly build warnings:
CC arch/ia64/ia32/sys_ia32.o
In file included from arch/ia64/ia32/sys_ia32.c:55:
arch/ia64/ia32/ia32priv.h:290:1: warning: "elf_check_arch" redefined
In file included from include/linux/elf.h:7,
from include/linux/module.h:14,
from include/linux/ftrace.h:8,
from include/linux/syscalls.h:68,
from arch/ia64/ia32/sys_ia32.c:18:
arch/ia64/include/asm/elf.h:19:1: warning: this is the location of the previous definition
[...]
sys_ia32.c includes linux/syscalls.h which in turn includes linux/ftrace.h
to import the syscalls tracing prototypes.
But including ftrace.h can pull too much things for a low level file,
especially on ia64 where the ia32 private headers conflict with higher
level headers.
Now we isolate the syscall tracing headers in their own lightweight file.
Reported-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jason Baron <jbaron@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Davidson <md@google.com>
LKML-Reference: <20090408184058.GB6017@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: we have gathered quite a few conflicts, need to merge upstream
Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/hardirq.h
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/irq.c
arch/x86/kernel/syscall_table_32.S
arch/x86/mm/iomap_32.c
include/linux/sched.h
kernel/Makefile
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
tracing, net: fix net tree and tracing tree merge interaction
tracing, powerpc: fix powerpc tree and tracing tree interaction
ring-buffer: do not remove reader page from list on ring buffer free
function-graph: allow unregistering twice
trace: make argument 'mem' of trace_seq_putmem() const
tracing: add missing 'extern' keywords to trace_output.h
tracing: provide trace_seq_reserve()
blktrace: print out BLK_TN_MESSAGE properly
blktrace: extract duplidate code
blktrace: fix memory leak when freeing struct blk_io_trace
blktrace: fix blk_probes_ref chaos
blktrace: make classic output more classic
blktrace: fix off-by-one bug
blktrace: fix the original blktrace
blktrace: fix a race when creating blk_tree_root in debugfs
blktrace: fix timestamp in binary output
tracing, Text Edit Lock: cleanup
tracing: filter fix for TRACE_EVENT_FORMAT events
ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
x86: kretprobe-booster interrupt emulation code fix
...
Fix up trivial conflicts in
arch/parisc/include/asm/ftrace.h
include/linux/memory.h
kernel/extable.c
kernel/module.c
Instead of always splitting the file offset into 32-bit 'high' and 'low'
parts, just split them into the largest natural word-size - which in C
terms is 'unsigned long'.
This allows 64-bit architectures to avoid the unnecessary 32-bit
shifting and masking for native format (while the compat interfaces will
obviously always have to do it).
This also changes the order of 'high' and 'low' to be "low first". Why?
Because when we have it like this, the 64-bit system calls now don't use
the "pos_high" argument at all, and it makes more sense for the native
system call to simply match the user-mode prototype.
This results in a much more natural calling convention, and allows the
compiler to generate much more straightforward code. On x86-64, we now
generate
testq %rcx, %rcx # pos_l
js .L122 #,
movq %rcx, -48(%rbp) # pos_l, pos
from the C source
loff_t pos = pos_from_hilo(pos_h, pos_l);
...
if (pos < 0)
return -EINVAL;
and the 'pos_h' register isn't even touched. It used to generate code
like
mov %r8d, %r8d # pos_low, pos_low
salq $32, %rcx #, tmp71
movq %r8, %rax # pos_low, pos.386
orq %rcx, %rax # tmp71, pos.386
js .L122 #,
movq %rax, -48(%rbp) # pos.386, pos
which isn't _that_ horrible, but it does show how the natural word size
is just a more sensible interface (same arguments will hold in the user
level glibc wrapper function, of course, so the kernel side is just half
of the equation!)
Note: in all cases the user code wrapper can again be the same. You can
just do
#define HALF_BITS (sizeof(unsigned long)*4)
__syscall(PWRITEV, fd, iov, count, offset, (offset >> HALF_BITS) >> HALF_BITS);
or something like that. That way the user mode wrapper will also be
nicely passing in a zero (it won't actually have to do the shifts, the
compiler will understand what is going on) for the last argument.
And that is a good idea, even if nobody will necessarily ever care: if
we ever do move to a 128-bit lloff_t, this particular system call might
be left alone. Of course, that will be the least of our worries if we
really ever need to care, so this may not be worth really caring about.
[ Fixed for lost 'loff_t' cast noticed by Andrew Morton ]
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds preadv and pwritev system calls. These syscalls are a
pretty straightforward combination of pread and readv (same for write).
They are quite useful for doing vectored I/O in threaded applications.
Using lseek+readv instead opens race windows you'll have to plug with
locking.
Other systems have such system calls too, for example NetBSD, check
here: http://www.daemon-systems.org/man/preadv.2.html
The application-visible interface provided by glibc should look like
this to be compatible to the existing implementations in the *BSD family:
ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);
This prototype has one problem though: On 32bit archs is the (64bit)
offset argument unaligned, which the syscall ABI of several archs doesn't
allow to do. At least s390 needs a wrapper in glibc to handle this. As
we'll need a wrappers in glibc anyway I've decided to push problem to
glibc entriely and use a syscall prototype which works without
arch-specific wrappers inside the kernel: The offset argument is
explicitly splitted into two 32bit values.
The patch sports the actual system call implementation and the windup in
the x86 system call tables. Other archs follow as separate patches.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: new feature
This adds the generic support for syscalls tracing. This is
currently exploited through a devoted tracer but other tracing
engines can use it. (They just have to play with
{start,stop}_ftrace_syscalls() and use the display callbacks
unless they want to override them.)
The syscalls prototypes definitions are abused here to steal
some metadata informations:
- syscall name, param types, param names, number of params
The syscall addr is not directly saved during this definition
because we don't know if its prototype is available in the
namespace. But we don't really need it. The arch has just to
build a function able to resolve the syscall number to its
metadata struct.
The current tracer prints the syscall names, parameters names
and values (and their types optionally). Currently the value is
a raw hex but higher level values diplaying is on my TODO list.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1236955332-10133-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: ABI change
This expands several fields in the perf_counter_hw_event struct and adds
a "flags" argument to the perf_counter_open system call, in order that
features can be added in future without ABI changes.
In particular the record_type field is expanded to 64 bits, and the
space for flag bits has been expanded from 32 to 64 bits.
This also adds some new fields:
* read_format (64 bits) is intended to provide a way to specify what
userspace wants to get back when it does a read() on a simple
(non-interrupting) counter;
* exclude_idle (1 bit) provides a way for userspace to ask that events
that occur when the cpu is idle be excluded;
* extra_config_len will provide a way for userspace to supply an
arbitrary amount of extra machine-specific PMU configuration data
immediately following the perf_counter_hw_event struct, to allow
sophisticated users to program things such as instruction matching
CAMs and address range registers;
* __reserved_3 and __reserved_4 provide space for future expansion.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This fixes three issues noticed by Arnd Bergmann:
- Add #ifdef __KERNEL__ and move some things around in perf_counter.h
to make sure only the bits that userspace needs are exported to
userspace.
- Use __u64, __s64, __u32 types in the structs exported to userspace
rather than u64, s64, u32.
- Make the sys_perf_counter_open syscall available to the SPUs on
Cell platforms.
And one issue that I noticed in looking at the code again:
- Wrap the perf_counter_open syscall with SYSCALL_DEFINE4 so we get
the proper handling of int arguments on ppc64 (and some other 64-bit
architectures).
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
With the new system call defines we get this on uml:
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x308): undefined reference to `sys_sigprocmask'
Reason for this is that uml passes the preprocessor option
-Dsigprocmask=kernel_sigprocmask to gcc when compiling the kernel.
This causes SYSCALL_DEFINE3(sigprocmask, ...) to be expanded to
SYSCALL_DEFINEx(3, kernel_sigprocmask, ...) and finally to a system
call named sys_kernel_sigprocmask. However sys_sigprocmask is missing
because of this.
To avoid macro expansion for the system call name just concatenate the
name at first define instead of carrying it through severel levels.
This was pointed out by Al Viro.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: WANG Cong <wangcong@zeuux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This enables the use of syscall wrappers to do proper sign extension
for 64-bit programs.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
By selecting HAVE_SYSCALL_WRAPPERS architectures can activate
system call wrappers in order to sign extend system call arguments.
All architectures where the ABI defines that the caller of a function
has to perform sign extension probably need this.
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Convert all system calls to return a long. This should be a NOP since all
converted types should have the same size anyway.
With the exception of sys_exit_group which returned void. But that doesn't
matter since the system call doesn't return.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
The problems lie in the types used for some inotify interfaces, both at the kernel level and at the glibc level. This mail addresses the kernel problem. I will follow up with some suggestions for glibc changes.
For the sys_inotify_rm_watch() interface, the type of the 'wd' argument is
currently 'u32', it should be '__s32' . That is Robert's suggestion, and
is consistent with the other declarations of watch descriptors in the
kernel source, in particular, the inotify_event structure in
include/linux/inotify.h:
struct inotify_event {
__s32 wd; /* watch descriptor */
__u32 mask; /* watch mask */
__u32 cookie; /* cookie to synchronize two events */
__u32 len; /* length (including nulls) of name */
char name[0]; /* stub for possible name */
};
The patch makes the changes needed for inotify_rm_watch().
Signed-off-by: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Robert Love <rlove@google.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Impact: clean up new API
Thorough cleanup of the new perf counters API, we now get clean separation
of the various concepts:
- introduce perf_counter_hw_event to separate out the event source details
- move special type flags into separate attributes: PERF_COUNT_NMI,
PERF_COUNT_RAW
- extend the type to u64 and reserve it fully to the architecture in the
raw type case.
And make use of all these changes in the core and x86 perfcounters code.
Also change the syscall signature to:
asmlinkage int sys_perf_counter_open(
struct perf_counter_hw_event *hw_event_uptr __user,
pid_t pid,
int cpu,
int group_fd);
( Note that group_fd is unused for now - it's reserved for the counter
groups abstraction. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Implement the core kernel bits of Performance Counters subsystem.
The Linux Performance Counter subsystem provides an abstraction of
performance counter hardware capabilities. It provides per task and per
CPU counters, and it provides event capabilities on top of those.
Performance counters are accessed via special file descriptors.
There's one file descriptor per virtual counter used.
The special file descriptor is opened via the perf_counter_open()
system call:
int
perf_counter_open(u32 hw_event_type,
u32 hw_event_period,
u32 record_type,
pid_t pid,
int cpu);
The syscall returns the new fd. The fd can be used via the normal
VFS system calls: read() can be used to read the counter, fcntl()
can be used to set the blocking mode, etc.
Multiple counters can be kept open at a time, and the counters
can be poll()ed.
See more details in Documentation/perf-counters.txt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce a new accept4() system call. The addition of this system call
matches analogous changes in 2.6.27 (dup3(), evenfd2(), signalfd4(),
inotify_init1(), epoll_create1(), pipe2()) which added new system calls
that differed from analogous traditional system calls in adding a flags
argument that can be used to access additional functionality.
The accept4() system call is exactly the same as accept(), except that
it adds a flags bit-mask argument. Two flags are initially implemented.
(Most of the new system calls in 2.6.27 also had both of these flags.)
SOCK_CLOEXEC causes the close-on-exec (FD_CLOEXEC) flag to be enabled
for the new file descriptor returned by accept4(). This is a useful
security feature to avoid leaking information in a multithreaded
program where one thread is doing an accept() at the same time as
another thread is doing a fork() plus exec(). More details here:
http://udrepper.livejournal.com/20407.html "Secure File Descriptor Handling",
Ulrich Drepper).
The other flag is SOCK_NONBLOCK, which causes the O_NONBLOCK flag
to be enabled on the new open file description created by accept4().
(This flag is merely a convenience, saving the use of additional calls
fcntl(F_GETFL) and fcntl (F_SETFL) to achieve the same result.
Here's a test program. Works on x86-32. Should work on x86-64, but
I (mtk) don't have a system to hand to test with.
It tests accept4() with each of the four possible combinations of
SOCK_CLOEXEC and SOCK_NONBLOCK set/clear in 'flags', and verifies
that the appropriate flags are set on the file descriptor/open file
description returned by accept4().
I tested Ulrich's patch in this thread by applying against 2.6.28-rc2,
and it passes according to my test program.
/* test_accept4.c
Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk
<mtk.manpages@gmail.com>
Licensed under the GNU GPLv2 or later.
*/
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#define PORT_NUM 33333
#define die(msg) do { perror(msg); exit(EXIT_FAILURE); } while (0)
/**********************************************************************/
/* The following is what we need until glibc gets a wrapper for
accept4() */
/* Flags for socket(), socketpair(), accept4() */
#ifndef SOCK_CLOEXEC
#define SOCK_CLOEXEC O_CLOEXEC
#endif
#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK O_NONBLOCK
#endif
#ifdef __x86_64__
#define SYS_accept4 288
#elif __i386__
#define USE_SOCKETCALL 1
#define SYS_ACCEPT4 18
#else
#error "Sorry -- don't know the syscall # on this architecture"
#endif
static int
accept4(int fd, struct sockaddr *sockaddr, socklen_t *addrlen, int flags)
{
printf("Calling accept4(): flags = %x", flags);
if (flags != 0) {
printf(" (");
if (flags & SOCK_CLOEXEC)
printf("SOCK_CLOEXEC");
if ((flags & SOCK_CLOEXEC) && (flags & SOCK_NONBLOCK))
printf(" ");
if (flags & SOCK_NONBLOCK)
printf("SOCK_NONBLOCK");
printf(")");
}
printf("\n");
#if USE_SOCKETCALL
long args[6];
args[0] = fd;
args[1] = (long) sockaddr;
args[2] = (long) addrlen;
args[3] = flags;
return syscall(SYS_socketcall, SYS_ACCEPT4, args);
#else
return syscall(SYS_accept4, fd, sockaddr, addrlen, flags);
#endif
}
/**********************************************************************/
static int
do_test(int lfd, struct sockaddr_in *conn_addr,
int closeonexec_flag, int nonblock_flag)
{
int connfd, acceptfd;
int fdf, flf, fdf_pass, flf_pass;
struct sockaddr_in claddr;
socklen_t addrlen;
printf("=======================================\n");
connfd = socket(AF_INET, SOCK_STREAM, 0);
if (connfd == -1)
die("socket");
if (connect(connfd, (struct sockaddr *) conn_addr,
sizeof(struct sockaddr_in)) == -1)
die("connect");
addrlen = sizeof(struct sockaddr_in);
acceptfd = accept4(lfd, (struct sockaddr *) &claddr, &addrlen,
closeonexec_flag | nonblock_flag);
if (acceptfd == -1) {
perror("accept4()");
close(connfd);
return 0;
}
fdf = fcntl(acceptfd, F_GETFD);
if (fdf == -1)
die("fcntl:F_GETFD");
fdf_pass = ((fdf & FD_CLOEXEC) != 0) ==
((closeonexec_flag & SOCK_CLOEXEC) != 0);
printf("Close-on-exec flag is %sset (%s); ",
(fdf & FD_CLOEXEC) ? "" : "not ",
fdf_pass ? "OK" : "failed");
flf = fcntl(acceptfd, F_GETFL);
if (flf == -1)
die("fcntl:F_GETFD");
flf_pass = ((flf & O_NONBLOCK) != 0) ==
((nonblock_flag & SOCK_NONBLOCK) !=0);
printf("nonblock flag is %sset (%s)\n",
(flf & O_NONBLOCK) ? "" : "not ",
flf_pass ? "OK" : "failed");
close(acceptfd);
close(connfd);
printf("Test result: %s\n", (fdf_pass && flf_pass) ? "PASS" : "FAIL");
return fdf_pass && flf_pass;
}
static int
create_listening_socket(int port_num)
{
struct sockaddr_in svaddr;
int lfd;
int optval;
memset(&svaddr, 0, sizeof(struct sockaddr_in));
svaddr.sin_family = AF_INET;
svaddr.sin_addr.s_addr = htonl(INADDR_ANY);
svaddr.sin_port = htons(port_num);
lfd = socket(AF_INET, SOCK_STREAM, 0);
if (lfd == -1)
die("socket");
optval = 1;
if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &optval,
sizeof(optval)) == -1)
die("setsockopt");
if (bind(lfd, (struct sockaddr *) &svaddr,
sizeof(struct sockaddr_in)) == -1)
die("bind");
if (listen(lfd, 5) == -1)
die("listen");
return lfd;
}
int
main(int argc, char *argv[])
{
struct sockaddr_in conn_addr;
int lfd;
int port_num;
int passed;
passed = 1;
port_num = (argc > 1) ? atoi(argv[1]) : PORT_NUM;
memset(&conn_addr, 0, sizeof(struct sockaddr_in));
conn_addr.sin_family = AF_INET;
conn_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
conn_addr.sin_port = htons(port_num);
lfd = create_listening_socket(port_num);
if (!do_test(lfd, &conn_addr, 0, 0))
passed = 0;
if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, 0))
passed = 0;
if (!do_test(lfd, &conn_addr, 0, SOCK_NONBLOCK))
passed = 0;
if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, SOCK_NONBLOCK))
passed = 0;
close(lfd);
exit(passed ? EXIT_SUCCESS : EXIT_FAILURE);
}
[mtk.manpages@gmail.com: rewrote changelog, updated test program]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduced by commit aaca0bdca5 ("flag
parameters: paccept"):
net/socket.c:1515:17: error: symbol 'sys_paccept' redeclared with different type (originally declared at include/linux/syscalls.h:413) - incompatible argument 4 (different address spaces)
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces the new syscall inotify_init1 (note: the 1 stands for
the one parameter the syscall takes, as opposed to no parameter before). The
values accepted for this parameter are function-specific and defined in the
inotify.h header. Here the values must match the O_* flags, though. In this
patch CLOEXEC support is introduced.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_inotify_init1
# ifdef __x86_64__
# define __NR_inotify_init1 294
# elif defined __i386__
# define __NR_inotify_init1 332
# else
# error "need __NR_inotify_init1"
# endif
#endif
#define IN_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd;
fd = syscall (__NR_inotify_init1, 0);
if (fd == -1)
{
puts ("inotify_init1(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("inotify_init1(0) set close-on-exit");
return 1;
}
close (fd);
fd = syscall (__NR_inotify_init1, IN_CLOEXEC);
if (fd == -1)
{
puts ("inotify_init1(IN_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("inotify_init1(O_CLOEXEC) does not set close-on-exit");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the new dup3 syscall. It extends the old dup2 syscall by one
parameter which is meant to hold a flag value. Support for the O_CLOEXEC flag
is added in this patch.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_dup3
# ifdef __x86_64__
# define __NR_dup3 292
# elif defined __i386__
# define __NR_dup3 330
# else
# error "need __NR_dup3"
# endif
#endif
int
main (void)
{
int fd = syscall (__NR_dup3, 1, 4, 0);
if (fd == -1)
{
puts ("dup3(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("dup3(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_dup3, 1, 4, O_CLOEXEC);
if (fd == -1)
{
puts ("dup3(O_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("dup3(O_CLOEXEC) set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the new epoll_create2 syscall. It extends the old epoll_create
syscall by one parameter which is meant to hold a flag value. In this
patch the only flag support is EPOLL_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.
A new name EPOLL_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_epoll_create2
# ifdef __x86_64__
# define __NR_epoll_create2 291
# elif defined __i386__
# define __NR_epoll_create2 329
# else
# error "need __NR_epoll_create2"
# endif
#endif
#define EPOLL_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd = syscall (__NR_epoll_create2, 1, 0);
if (fd == -1)
{
puts ("epoll_create2(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("epoll_create2(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_epoll_create2, 1, EPOLL_CLOEXEC);
if (fd == -1)
{
puts ("epoll_create2(EPOLL_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("epoll_create2(EPOLL_CLOEXEC) set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the new eventfd2 syscall. It extends the old eventfd
syscall by one parameter which is meant to hold a flag value. In this
patch the only flag support is EFD_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.
A new name EFD_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_eventfd2
# ifdef __x86_64__
# define __NR_eventfd2 290
# elif defined __i386__
# define __NR_eventfd2 328
# else
# error "need __NR_eventfd2"
# endif
#endif
#define EFD_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd = syscall (__NR_eventfd2, 1, 0);
if (fd == -1)
{
puts ("eventfd2(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("eventfd2(0) sets close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_eventfd2, 1, EFD_CLOEXEC);
if (fd == -1)
{
puts ("eventfd2(EFD_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("eventfd2(EFD_CLOEXEC) does not set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the new signalfd4 syscall. It extends the old signalfd
syscall by one parameter which is meant to hold a flag value. In this
patch the only flag support is SFD_CLOEXEC which causes the close-on-exec
flag for the returned file descriptor to be set.
A new name SFD_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_signalfd4
# ifdef __x86_64__
# define __NR_signalfd4 289
# elif defined __i386__
# define __NR_signalfd4 327
# else
# error "need __NR_signalfd4"
# endif
#endif
#define SFD_CLOEXEC O_CLOEXEC
int
main (void)
{
sigset_t ss;
sigemptyset (&ss);
sigaddset (&ss, SIGUSR1);
int fd = syscall (__NR_signalfd4, -1, &ss, 8, 0);
if (fd == -1)
{
puts ("signalfd4(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("signalfd4(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_signalfd4, -1, &ss, 8, SFD_CLOEXEC);
if (fd == -1)
{
puts ("signalfd4(SFD_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("signalfd4(SFD_CLOEXEC) does not set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is by far the most complex in the series. It adds a new syscall
paccept. This syscall differs from accept in that it adds (at the userlevel)
two additional parameters:
- a signal mask
- a flags value
The flags parameter can be used to set flag like SOCK_CLOEXEC. This is
imlpemented here as well. Some people argued that this is a property which
should be inherited from the file desriptor for the server but this is against
POSIX. Additionally, we really want the signal mask parameter as well
(similar to pselect, ppoll, etc). So an interface change in inevitable.
The flag value is the same as for socket and socketpair. I think diverging
here will only create confusion. Similar to the filesystem interfaces where
the use of the O_* constants differs, it is acceptable here.
The signal mask is handled as for pselect etc. The mask is temporarily
installed for the thread and removed before the call returns. I modeled the
code after pselect. If there is a problem it's likely also in pselect.
For architectures which use socketcall I maintained this interface instead of
adding a system call. The symmetry shouldn't be broken.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#ifndef __NR_paccept
# ifdef __x86_64__
# define __NR_paccept 288
# elif defined __i386__
# define SYS_PACCEPT 18
# define USE_SOCKETCALL 1
# else
# error "need __NR_paccept"
# endif
#endif
#ifdef USE_SOCKETCALL
# define paccept(fd, addr, addrlen, mask, flags) \
({ long args[6] = { \
(long) fd, (long) addr, (long) addrlen, (long) mask, 8, (long) flags }; \
syscall (__NR_socketcall, SYS_PACCEPT, args); })
#else
# define paccept(fd, addr, addrlen, mask, flags) \
syscall (__NR_paccept, fd, addr, addrlen, mask, 8, flags)
#endif
#define PORT 57392
#define SOCK_CLOEXEC O_CLOEXEC
static pthread_barrier_t b;
static void *
tf (void *arg)
{
pthread_barrier_wait (&b);
int s = socket (AF_INET, SOCK_STREAM, 0);
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
sin.sin_port = htons (PORT);
connect (s, (const struct sockaddr *) &sin, sizeof (sin));
close (s);
pthread_barrier_wait (&b);
s = socket (AF_INET, SOCK_STREAM, 0);
sin.sin_port = htons (PORT);
connect (s, (const struct sockaddr *) &sin, sizeof (sin));
close (s);
pthread_barrier_wait (&b);
pthread_barrier_wait (&b);
sleep (2);
pthread_kill ((pthread_t) arg, SIGUSR1);
return NULL;
}
static void
handler (int s)
{
}
int
main (void)
{
pthread_barrier_init (&b, NULL, 2);
struct sockaddr_in sin;
pthread_t th;
if (pthread_create (&th, NULL, tf, (void *) pthread_self ()) != 0)
{
puts ("pthread_create failed");
return 1;
}
int s = socket (AF_INET, SOCK_STREAM, 0);
int reuse = 1;
setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof (reuse));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
sin.sin_port = htons (PORT);
bind (s, (struct sockaddr *) &sin, sizeof (sin));
listen (s, SOMAXCONN);
pthread_barrier_wait (&b);
int s2 = paccept (s, NULL, 0, NULL, 0);
if (s2 < 0)
{
puts ("paccept(0) failed");
return 1;
}
int coe = fcntl (s2, F_GETFD);
if (coe & FD_CLOEXEC)
{
puts ("paccept(0) set close-on-exec-flag");
return 1;
}
close (s2);
pthread_barrier_wait (&b);
s2 = paccept (s, NULL, 0, NULL, SOCK_CLOEXEC);
if (s2 < 0)
{
puts ("paccept(SOCK_CLOEXEC) failed");
return 1;
}
coe = fcntl (s2, F_GETFD);
if ((coe & FD_CLOEXEC) == 0)
{
puts ("paccept(SOCK_CLOEXEC) does not set close-on-exec flag");
return 1;
}
close (s2);
pthread_barrier_wait (&b);
struct sigaction sa;
sa.sa_handler = handler;
sa.sa_flags = 0;
sigemptyset (&sa.sa_mask);
sigaction (SIGUSR1, &sa, NULL);
sigset_t ss;
pthread_sigmask (SIG_SETMASK, NULL, &ss);
sigaddset (&ss, SIGUSR1);
pthread_sigmask (SIG_SETMASK, &ss, NULL);
sigdelset (&ss, SIGUSR1);
alarm (4);
pthread_barrier_wait (&b);
errno = 0 ;
s2 = paccept (s, NULL, 0, &ss, 0);
if (s2 != -1 || errno != EINTR)
{
puts ("paccept did not fail with EINTR");
return 1;
}
close (s);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[akpm@linux-foundation.org: make it compile]
[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Roland McGrath <roland@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Trying to compile the v850 port brings many compile errors, one of them exists
since at least kernel 2.6.19.
There also seems to be noone willing to bring this port back into a usable
state.
This patch therefore removes the v850 port.
If anyone ever decides to revive the v850 port the code will still be
available from older kernels, and it wouldn't be impossible for the port to
reenter the kernel if it would become actively maintained again.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add missing consts to xattr function arguments.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they (or some user of them) rely
on it dragging in some unrelated header file, but I can't build all
these files, so we'll have to fix any build failures as they come up.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
This is the new timerfd API as it is implemented by the following patch:
int timerfd_create(int clockid, int flags);
int timerfd_settime(int ufd, int flags,
const struct itimerspec *utmr,
struct itimerspec *otmr);
int timerfd_gettime(int ufd, struct itimerspec *otmr);
The timerfd_create() API creates an un-programmed timerfd fd. The "clockid"
parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME.
The timerfd_settime() API give new settings by the timerfd fd, by optionally
retrieving the previous expiration time (in case the "otmr" parameter is not
NULL).
The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit
is set in the "flags" parameter. Otherwise it's a relative time.
The timerfd_gettime() API returns the next expiration time of the timer, or
{0, 0} if the timerfd has not been set yet.
Like the previous timerfd API implementation, read(2) and poll(2) are
supported (with the same interface). Here's a simple test program I used to
exercise the new timerfd APIs:
http://www.xmailserver.org/timerfd-test2.c
[akpm@linux-foundation.org: coding-style cleanups]
[akpm@linux-foundation.org: fix ia64 build]
[akpm@linux-foundation.org: fix m68k build]
[akpm@linux-foundation.org: fix mips build]
[akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds]
[heiko.carstens@de.ibm.com: fix s390]
[akpm@linux-foundation.org: fix powerpc build]
[akpm@linux-foundation.org: fix sparc64 more]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds support for additional flags at spu_create, which relate
to the establishment of affinity between contexts and contexts to memory.
A fourth, optional, parameter is supported. This parameter represent
a affinity neighbor of the context being created, and is used when defining
SPU-SPU affinity.
Affinity is represented as a doubly linked list of spu_contexts.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
fallocate() is a new system call being proposed here which will allow
applications to preallocate space to any file(s) in a file system.
Each file system implementation that wants to use this feature will need
to support an inode operation called ->fallocate().
Applications can use this feature to avoid fragmentation to certain
level and thus get faster access speed. With preallocation, applications
also get a guarantee of space for particular file(s) - even if later the
the system becomes full.
Currently, glibc provides an interface called posix_fallocate() which
can be used for similar cause. Though this has the advantage of working
on all file systems, but it is quite slow (since it writes zeroes to
each block that has to be preallocated). Without a doubt, file systems
can do this more efficiently within the kernel, by implementing
the proposed fallocate() system call. It is expected that
posix_fallocate() will be modified to call this new system call first
and incase the kernel/filesystem does not implement it, it should fall
back to the current implementation of writing zeroes to the new blocks.
ToDos:
1. Implementation on other architectures (other than i386, x86_64,
and ppc). Patches for s390(x) and ia64 are already available from
previous posts, but it was decided that they should be added later
once fallocate is in the mainline. Hence not including those patches
in this take.
2. Changes to glibc,
a) to support fallocate() system call
b) to make posix_fallocate() and posix_fallocate64() call fallocate()
Signed-off-by: Amit Arora <aarora@in.ibm.com>
Not all the world is an i386. Many architectures need 64-bit arguments to be
aligned in suitable pairs of registers, and the original
sys_sync_file_range(int, loff_t, loff_t, int) was therefore wasting an
argument register for padding after the first integer. Since we don't
normally have more than 6 arguments for system calls, that left no room for
the final argument on some architectures.
Fix this by introducing sys_sync_file_range2(int, int, loff_t, loff_t) which
all fits nicely. In fact, ARM already had that, but called it
sys_arm_sync_file_range. Move it to fs/sync.c and rename it, then implement
the needed compatibility routine. And stop the missing syscall check from
bitching about the absence of sys_sync_file_range() if we've implemented
sys_sync_file_range2() instead.
Tested on PPC32 and with 32-bit and 64-bit userspace on PPC64.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a very simple and light file descriptor, that can be used as event
wait/dispatch by userspace (both wait and dispatch) and by the kernel
(dispatch only). It can be used instead of pipe(2) in all cases where those
would simply be used to signal events. Their kernel overhead is much lower
than pipes, and they do not consume two fds. When used in the kernel, it can
offer an fd-bridge to enable, for example, functionalities like KAIO or
syslets/threadlets to signal to an fd the completion of certain operations.
But more in general, an eventfd can be used by the kernel to signal readiness,
in a POSIX poll/select way, of interfaces that would otherwise be incompatible
with it. The API is:
int eventfd(unsigned int count);
The eventfd API accepts an initial "count" parameter, and returns an eventfd
fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2).
The POLLIN flag is raised when the internal counter is greater than zero.
The POLLOUT flag is raised when at least a value of "1" can be written to the
internal counter.
The POLLERR flag is raised when an overflow in the counter value is detected.
The write(2) operation can never overflow the counter, since it blocks (unless
O_NONBLOCK is set, in which case -EAGAIN is returned).
But the eventfd_signal() function can do it, since it's supposed to not sleep
during its operation.
The read(2) function reads the __u64 counter value, and reset the internal
value to zero. If the value read is equal to (__u64) -1, an overflow happened
on the internal counter (due to 2^64 eventfd_signal() posts that has never
been retired - unlickely, but possible).
The write(2) call writes an __u64 count value, and adds it to the current
counter. The eventfd fd supports O_NONBLOCK also.
On the kernel side, we have:
struct file *eventfd_fget(int fd);
int eventfd_signal(struct file *file, unsigned int n);
The eventfd_fget() should be called to get a struct file* from an eventfd fd
(this is an fget() + check of f_op being an eventfd fops pointer).
The kernel can then call eventfd_signal() every time it wants to post an event
to userspace. The eventfd_signal() function can be called from any context.
An eventfd() simple test and bench is available here:
http://www.xmailserver.org/eventfd-bench.c
This is the eventfd-based version of pipetest-4 (pipe(2) based):
http://www.xmailserver.org/pipetest-4.c
Not that performance matters much in the eventfd case, but eventfd-bench
shows almost as double as performance than pipetest-4.
[akpm@linux-foundation.org: fix i386 build]
[akpm@linux-foundation.org: add sys_eventfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces a new system call for timers events delivered though
file descriptors. This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2). As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd). If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be
returned.
The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.
The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.
If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};
[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is needed before Powerpc can wire up the syscall.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement the epoll_pwait system call, that extend the event wait mechanism
with the same logic ppoll and pselect do. The definition of epoll_pwait
is:
int epoll_pwait(int epfd, struct epoll_event *events, int maxevents,
int timeout, const sigset_t *sigmask, size_t sigsetsize);
The difference between the vanilla epoll_wait and epoll_pwait is that the
latter allows the caller to specify a signal mask to be set while waiting
for events. Hence epoll_pwait will wait until either one monitored event,
or an unmasked signal happen. If sigmask is NULL, the epoll_pwait system
call will act exactly like epoll_wait. For the POSIX definition of
pselect, information is available here:
http://www.opengroup.org/onlinepubs/009695399/functions/select.html
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some architectures provide an execve function that does not set errno, but
instead returns the result code directly. Rename these to kernel_execve to
get the right semantics there. Moreover, there is no reasone for any of these
architectures to still provide __KERNEL_SYSCALLS__ or _syscallN macros, so
remove these right away.
[akpm@osdl.org: build fix]
[bunk@stusta.de: build fix]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andi Kleen <ak@muc.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For NUMA optimization and some other algorithms it is useful to have a fast
to get the current CPU and node numbers in user space.
x86-64 added a fast way to do this in a vsyscall. This adds a generic
syscall for other architectures to make it a generic portable facility.
I expect some of them will also implement it as a faster vsyscall.
The cache is an optimization for the x86-64 vsyscall optimization. Since
what the syscall returns is an approximation anyways and user space
often wants very fast results it can be cached for some time. The norma
methods to get this information in user space are relatively slow
The vsyscall is in a better position to manage the cache because it has direct
access to a fast time stamp (jiffies). For the generic syscall optimization
it doesn't help much, but enforce a valid argument to keep programs
portable
I only added an i386 syscall entry for now. Other architectures can follow
as needed.
AK: Also added some cleanups from Andrew Morton
Signed-off-by: Andi Kleen <ak@suse.de>
We are pleased to announce "lightweight userspace priority inheritance" (PI)
support for futexes. The following patchset and glibc patch implements it,
ontop of the robust-futexes patchset which is included in 2.6.16-mm1.
We are calling it lightweight for 3 reasons:
- in the user-space fastpath a PI-enabled futex involves no kernel work
(or any other PI complexity) at all. No registration, no extra kernel
calls - just pure fast atomic ops in userspace.
- in the slowpath (in the lock-contention case), the system call and
scheduling pattern is in fact better than that of normal futexes, due to
the 'integrated' nature of FUTEX_LOCK_PI. [more about that further down]
- the in-kernel PI implementation is streamlined around the mutex
abstraction, with strict rules that keep the implementation relatively
simple: only a single owner may own a lock (i.e. no read-write lock
support), only the owner may unlock a lock, no recursive locking, etc.
Priority Inheritance - why, oh why???
-------------------------------------
Many of you heard the horror stories about the evil PI code circling Linux for
years, which makes no real sense at all and is only used by buggy applications
and which has horrible overhead. Some of you have dreaded this very moment,
when someone actually submits working PI code ;-)
So why would we like to see PI support for futexes?
We'd like to see it done purely for technological reasons. We dont think it's
a buggy concept, we think it's useful functionality to offer to applications,
which functionality cannot be achieved in other ways. We also think it's the
right thing to do, and we think we've got the right arguments and the right
numbers to prove that. We also believe that we can address all the
counter-arguments as well. For these reasons (and the reasons outlined below)
we are submitting this patch-set for upstream kernel inclusion.
What are the benefits of PI?
The short reply:
----------------
User-space PI helps achieving/improving determinism for user-space
applications. In the best-case, it can help achieve determinism and
well-bound latencies. Even in the worst-case, PI will improve the statistical
distribution of locking related application delays.
The longer reply:
-----------------
Firstly, sharing locks between multiple tasks is a common programming
technique that often cannot be replaced with lockless algorithms. As we can
see it in the kernel [which is a quite complex program in itself], lockless
structures are rather the exception than the norm - the current ratio of
lockless vs. locky code for shared data structures is somewhere between 1:10
and 1:100. Lockless is hard, and the complexity of lockless algorithms often
endangers to ability to do robust reviews of said code. I.e. critical RT
apps often choose lock structures to protect critical data structures, instead
of lockless algorithms. Furthermore, there are cases (like shared hardware,
or other resource limits) where lockless access is mathematically impossible.
Media players (such as Jack) are an example of reasonable application design
with multiple tasks (with multiple priority levels) sharing short-held locks:
for example, a highprio audio playback thread is combined with medium-prio
construct-audio-data threads and low-prio display-colory-stuff threads. Add
video and decoding to the mix and we've got even more priority levels.
So once we accept that synchronization objects (locks) are an unavoidable fact
of life, and once we accept that multi-task userspace apps have a very fair
expectation of being able to use locks, we've got to think about how to offer
the option of a deterministic locking implementation to user-space.
Most of the technical counter-arguments against doing priority inheritance
only apply to kernel-space locks. But user-space locks are different, there
we cannot disable interrupts or make the task non-preemptible in a critical
section, so the 'use spinlocks' argument does not apply (user-space spinlocks
have the same priority inversion problems as other user-space locking
constructs). Fact is, pretty much the only technique that currently enables
good determinism for userspace locks (such as futex-based pthread mutexes) is
priority inheritance:
Currently (without PI), if a high-prio and a low-prio task shares a lock [this
is a quite common scenario for most non-trivial RT applications], even if all
critical sections are coded carefully to be deterministic (i.e. all critical
sections are short in duration and only execute a limited number of
instructions), the kernel cannot guarantee any deterministic execution of the
high-prio task: any medium-priority task could preempt the low-prio task while
it holds the shared lock and executes the critical section, and could delay it
indefinitely.
Implementation:
---------------
As mentioned before, the userspace fastpath of PI-enabled pthread mutexes
involves no kernel work at all - they behave quite similarly to normal
futex-based locks: a 0 value means unlocked, and a value==TID means locked.
(This is the same method as used by list-based robust futexes.) Userspace uses
atomic ops to lock/unlock these mutexes without entering the kernel.
To handle the slowpath, we have added two new futex ops:
FUTEX_LOCK_PI
FUTEX_UNLOCK_PI
If the lock-acquire fastpath fails, [i.e. an atomic transition from 0 to TID
fails], then FUTEX_LOCK_PI is called. The kernel does all the remaining work:
if there is no futex-queue attached to the futex address yet then the code
looks up the task that owns the futex [it has put its own TID into the futex
value], and attaches a 'PI state' structure to the futex-queue. The pi_state
includes an rt-mutex, which is a PI-aware, kernel-based synchronization
object. The 'other' task is made the owner of the rt-mutex, and the
FUTEX_WAITERS bit is atomically set in the futex value. Then this task tries
to lock the rt-mutex, on which it blocks. Once it returns, it has the mutex
acquired, and it sets the futex value to its own TID and returns. Userspace
has no other work to perform - it now owns the lock, and futex value contains
FUTEX_WAITERS|TID.
If the unlock side fastpath succeeds, [i.e. userspace manages to do a TID ->
0 atomic transition of the futex value], then no kernel work is triggered.
If the unlock fastpath fails (because the FUTEX_WAITERS bit is set), then
FUTEX_UNLOCK_PI is called, and the kernel unlocks the futex on the behalf of
userspace - and it also unlocks the attached pi_state->rt_mutex and thus wakes
up any potential waiters.
Note that under this approach, contrary to other PI-futex approaches, there is
no prior 'registration' of a PI-futex. [which is not quite possible anyway,
due to existing ABI properties of pthread mutexes.]
Also, under this scheme, 'robustness' and 'PI' are two orthogonal properties
of futexes, and all four combinations are possible: futex, robust-futex,
PI-futex, robust+PI-futex.
glibc support:
--------------
Ulrich Drepper and Jakub Jelinek have written glibc support for PI-futexes
(and robust futexes), enabling robust and PI (PTHREAD_PRIO_INHERIT) POSIX
mutexes. (PTHREAD_PRIO_PROTECT support will be added later on too, no
additional kernel changes are needed for that). [NOTE: The glibc patch is
obviously inofficial and unsupported without matching upstream kernel
functionality.]
the patch-queue and the glibc patch can also be downloaded from:
http://redhat.com/~mingo/PI-futex-patches/
Many thanks go to the people who helped us create this kernel feature: Steven
Rostedt, Esben Nielsen, Benedikt Spranger, Daniel Walker, John Cooper, Arjan
van de Ven, Oleg Nesterov and others. Credits for related prior projects goes
to Dirk Grambow, Inaky Perez-Gonzalez, Bill Huey and many others.
Clean up the futex code, before adding more features to it:
- use u32 as the futex field type - that's the ABI
- use __user and pointers to u32 instead of unsigned long
- code style / comment style cleanups
- rename hash-bucket name from 'bh' to 'hb'.
I checked the pre and post futex.o object files to make sure this
patch has no code effects.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The definition of the third parameter is a pointer to an array of virtual
addresses which give us some trouble. The existing code calculated the
wrong address in the array since I used void to avoid having to specify a
type.
I now use the correct type "compat_uptr_t __user *" in the definition of
the function in kernel/compat.c.
However, I used __u32 in syscalls.h. Would have to include compat.h there
in order to provide the same definition which would generate an ugly
include situation.
On both ia64 and x86_64 compat_uptr_t is u32. So this works although
parameter declarations differ.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
sys_move_pages() support for 32bit (i386 plus x86_64 compat layer)
Add support for move_pages() on i386 and also add the compat functions
necessary to run 32 bit binaries on x86_64.
Add compat_sys_move_pages to the x86_64 32bit binary layer. Note that it is
not up to date so I added the missing pieces. Not sure if this is done the
right way.
[akpm@osdl.org: compile fix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
move_pages() is used to move individual pages of a process. The function can
be used to determine the location of pages and to move them onto the desired
node. move_pages() returns status information for each page.
long move_pages(pid, number_of_pages_to_move,
addresses_of_pages[],
nodes[] or NULL,
status[],
flags);
The addresses of pages is an array of void * pointing to the
pages to be moved.
The nodes array contains the node numbers that the pages should be moved
to. If a NULL is passed instead of an array then no pages are moved but
the status array is updated. The status request may be used to determine
the page state before issuing another move_pages() to move pages.
The status array will contain the state of all individual page migration
attempts when the function terminates. The status array is only valid if
move_pages() completed successfullly.
Possible page states in status[]:
0..MAX_NUMNODES The page is now on the indicated node.
-ENOENT Page is not present
-EACCES Page is mapped by multiple processes and can only
be moved if MPOL_MF_MOVE_ALL is specified.
-EPERM The page has been mlocked by a process/driver and
cannot be moved.
-EBUSY Page is busy and cannot be moved. Try again later.
-EFAULT Invalid address (no VMA or zero page).
-ENOMEM Unable to allocate memory on target node.
-EIO Unable to write back page. The page must be written
back in order to move it since the page is dirty and the
filesystem does not provide a migration function that
would allow the moving of dirty pages.
-EINVAL A dirty page cannot be moved. The filesystem does not provide
a migration function and has no ability to write back pages.
The flags parameter indicates what types of pages to move:
MPOL_MF_MOVE Move pages that are only mapped by the process.
MPOL_MF_MOVE_ALL Also move pages that are mapped by multiple processes.
Requires sufficient capabilities.
Possible return codes from move_pages()
-ENOENT No pages found that would require moving. All pages
are either already on the target node, not present, had an
invalid address or could not be moved because they were
mapped by multiple processes.
-EINVAL Flags other than MPOL_MF_MOVE(_ALL) specified or an attempt
to migrate pages in a kernel thread.
-EPERM MPOL_MF_MOVE_ALL specified without sufficient priviledges.
or an attempt to move a process belonging to another user.
-EACCES One of the target nodes is not allowed by the current cpuset.
-ENODEV One of the target nodes is not online.
-ESRCH Process does not exist.
-E2BIG Too many pages to move.
-ENOMEM Not enough memory to allocate control array.
-EFAULT Parameters could not be accessed.
A test program for move_pages() may be found with the patches
on ftp.kernel.org:/pub/linux/kernel/people/christoph/pmig/patches-2.6.17-rc4-mm3
From: Christoph Lameter <clameter@sgi.com>
Detailed results for sys_move_pages()
Pass a pointer to an integer to get_new_page() that may be used to
indicate where the completion status of a migration operation should be
placed. This allows sys_move_pags() to report back exactly what happened to
each page.
Wish there would be a better way to do this. Looks a bit hacky.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
sys_splice() moves data to/from pipes with a file input/output. sys_vmsplice()
moves data to a pipe, with the input being a user address range instead.
This uses an approach suggested by Linus, where we can hold partial ranges
inside the pages[] map. Hopefully this will be useful for network
receive support as well.
Signed-off-by: Jens Axboe <axboe@suse.de>
Basically an in-kernel implementation of tee, which uses splice and the
pipe buffers as an intelligent way to pass data around by reference.
Where the user space tee consumes the input and produces a stdout and
file output, this syscall merely duplicates the data inside a pipe to
another pipe. No data is copied, the output just grabs a reference to the
input pipe data.
Signed-off-by: Jens Axboe <axboe@suse.de>
Ingo Molnar