01 May, 2013
40 commits
-
Simplify the logic of variable assignments.
[akpm@linux-foundation.org: replace min_t with min, remove unneeded casts]
Signed-off-by: Zhang Yanfei
Cc: "Eric W. Biederman"
Reviewed-by: Simon Horman
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The types of the following local variables:
- ubytes/mbytes in kimage_load_crash_segment()/kimage_load_normal_segment()
- r in vmcoreinfo_append_str()
are wrong, so fix them.
Signed-off-by: Zhang Yanfei
Cc: "Eric W. Biederman"
Cc: Simon Horman
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
threadgroup_lock() takes signal->cred_guard_mutex to ensure that
thread_group_leader() is stable. This doesn't look nice, the scope of
this lock in do_execve() is huge.And as Dave pointed out this can lead to deadlock, we have the
following dependencies:do_execve: cred_guard_mutex -> i_mutex
cgroup_mount: i_mutex -> cgroup_mutex
attach_task_by_pid: cgroup_mutex -> cred_guard_mutexChange de_thread() to take threadgroup_change_begin() around the
switch-the-leader code and change threadgroup_lock() to avoid
->cred_guard_mutex.Note that de_thread() can't sleep with ->group_rwsem held, this can
obviously deadlock with the exiting leader if the writer is active, so it
does threadgroup_change_end() before schedule().Reported-by: Dave Jones
Acked-by: Tejun Heo
Acked-by: Li Zefan
Signed-off-by: Oleg Nesterov
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
set_task_comm() does memset() + wmb() before strlcpy(). This buys
nothing and to add to the confusion, the comment is wrong.- We do not need memset() to be "safe from non-terminating string
reads", the final char is always zero and we never change it.- wmb() is paired with nothing, it cannot prevent from printing
the mixture of the old/new data unless the reader takes the lock.Signed-off-by: Oleg Nesterov
Cc: Andi Kleen
Cc: John Stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, a write to a procfs file will return the number of bytes
successfully written. If the actual string is longer than this, the
remainder of the string will not be be written and userspace will
complete the operation by issuing additional write()s.Hence
$ echo -n "abcdefghijklmnopqrs" > /proc/self/comm
results in
$ cat /proc/$$/comm
pqrssince the final four bytes were written with a second write() since
TASK_COMM_LEN == 16. This is obviously an undesired result and not
equivalent to prctl(PR_SET_NAME). The implementation should not need to
know the definition of TASK_COMM_LEN.This patch truncates the string to the first TASK_COMM_LEN bytes and
returns the bytes written as the length of the string written so the
second write() is suppressed.$ cat /proc/$$/comm
abcdefghijklmnoSigned-off-by: David Rientjes
Acked-by: John Stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
wait_for_dump_helpers() calls wake_up/kill_fasync from inside the
wait_event-like loop. This is not needed and in fact this is not
strictly correct, we can/should do this only once after we change
pipe->writers. We could even check if it becomes zero.Change this code to use use wait_event_interruptible(), this can also
help to make this wait freezable.With this patch we check pipe->readers without pipe_lock(), this is
fine. Once we see pipe->readers == 1 we know that the handler
decremented the counter, this is all we need.Signed-off-by: Oleg Nesterov
Acked-by: Mandeep Singh Baines
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Cleanup. Every linux_binfmt->core_dump() sets PF_DUMPCORE, move this into
zap_threads() called by do_coredump().Signed-off-by: Oleg Nesterov
Acked-by: Mandeep Singh Baines
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
By discussion with Mandeep.
Change dump_write(), dump_seek() and do_coredump() to check
signal_pending() and abort if it is true. dump_seek() does this only
before f_op->llseek(), otherwise it relies on dump_write().We need this change to ensure that the coredump won't delay suspend, and
to ensure it reacts to SIGKILL "quickly enough", a core dump can take a
lot of time. In particular this can help oom-killer.We add the new trivial helper, dump_interrupted() to add the comments and
to simplify the potential freezer changes. Perhaps it will have more
callers.Ideally it should do try_to_freeze() but then we need the unpleasant
changes in dump_write() and wait_for_dump_helpers(). It is not trivial to
change dump_write() to restart if f_op->write() fails because of
freezing(). We need to handle the short writes, we need to clear
TIF_SIGPENDING (and we can't rely on recalc_sigpending() unless we change
it to check PF_DUMPCORE). And if the buggy f_op->write() sets
TIF_SIGPENDING we can not distinguish this case from the race with
freeze_task() + __thaw_task().So we simply accept the fact that the freezer can truncate a core-dump but
at least you can reliably suspend. Hopefully we can tolerate this
unlikely case and the necessary complications doesn't worth a trouble.
But if we decide to make the coredumping freezable later we can do this on
top of this change.Signed-off-by: Oleg Nesterov
Acked-by: Mandeep Singh Baines
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that the coredumping process can be SIGKILL'ed, the setting of
->group_exit_code in do_coredump() can race with complete_signal() and
SIGKILL or 0x80 can be "lost", or wait(status) can report status ==
SIGKILL | 0x80.But the main problem is that it is not clear to me what should we do if
binfmt->core_dump() succeeds but SIGKILL was sent, that is why this patch
comes as a separate change.This patch adds 0x80 if ->core_dump() succeeds and the process was not
killed. But perhaps we can (should?) re-set ->group_exit_code changed by
SIGKILL back to "siginfo->si_signo |= 0x80" in case when core_dumped == T.Signed-off-by: Oleg Nesterov
Tested-by: Mandeep Singh Baines
Cc: Ingo Molnar
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Roland McGrath
Cc: Tejun Heo
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
prepare_signal() blesses SIGKILL sent to the dumping process but this
signal can be "lost" anyway. The problems is, complete_signal() sees
SIGNAL_GROUP_EXIT and skips the "kill them all" logic. And even if the
dumping process is single-threaded (so the target is always "correct"),
the group-wide SIGKILL is not recorded in task->pending and thus
__fatal_signal_pending() won't be true. A multi-threaded case has even
more problems.And even ignoring all technical details, SIGNAL_GROUP_EXIT doesn't look
right to me. This coredumping process is not exiting yet, it can do a lot
of work dumping the core.With this patch the dumping process doesn't have SIGNAL_GROUP_EXIT, we set
signal->group_exit_task instead. This makes signal_group_exit() true and
thus this should equally close the races with exit/exec/stop but allows to
kill the dumping thread reliably.Notes:
- It is not clear what should we do with ->group_exit_code
if the dumper was killed, see the next change.- we need more (hopefully straightforward) changes to ensure
that SIGKILL actually interrupts the coredump. Basically we
need to check __fatal_signal_pending() in dump_write() and
dump_seek().Signed-off-by: Oleg Nesterov
Tested-by: Mandeep Singh Baines
Cc: Ingo Molnar
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Roland McGrath
Cc: Tejun Heo
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There are 2 well known and ancient problems with coredump/signals, and a
lot of related bug reports:- do_coredump() clears TIF_SIGPENDING but of course this can't help
if, say, SIGCHLD comes after that.In this case the coredump can fail unexpectedly. See for example
wait_for_dump_helper()->signal_pending() check but there are other
reasons.- At the same time, dumping a huge core on the slow media can take a
lot of time/resources and there is no way to kill the coredumping
task reliably. In particular this is not oom_kill-friendly.This patch tries to fix the 1st problem, and makes the preparation for the
next changes.We add the new SIGNAL_GROUP_COREDUMP flag set by zap_threads() to indicate
that this process dumps the core. prepare_signal() checks this flag and
nacks any signal except SIGKILL.Note that this check tries to be conservative, in the long term we should
probably treat the SIGNAL_GROUP_EXIT case equally but this needs more
discussion. See marc.info/?l=linux-kernel&m=120508897917439Notes:
- recalc_sigpending() doesn't check SIGNAL_GROUP_COREDUMP.
The patch assumes that dump_write/etc paths should never
call it, but we can change it as well.- There is another source of TIF_SIGPENDING, freezer. This
will be addressed separately.Signed-off-by: Oleg Nesterov
Tested-by: Mandeep Singh Baines
Cc: Ingo Molnar
Cc: Neil Horman
Cc: "Rafael J. Wysocki"
Cc: Roland McGrath
Cc: Tejun Heo
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This function suffers from not being able to determine if the cleanup is
called in case it returns -ENOMEM. Nobody is using it anymore, so let's
remove it.Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Cc: David Howells
Cc: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These are the only users of call_usermodehelper_fns(). This function
suffers from not being able to determine if the cleanup is called. Even
if in this places the cleanup pointer is NULL, convert them to use the
separate call_usermodehelper_setup() + call_usermodehelper_exec()
functions so we can remove the _fns variant.Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Cc: David Howells
Cc: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Cc: David Howells
Cc: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use call_usermodehelper_setup() + call_usermodehelper_exec() instead of
calling call_usermodehelper_fns(). In case there's an OOM in this last
function the cleanup function may not be called - in this case we would
miss a call to key_put().Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Acked-by: David Howells
Acked-by: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use call_usermodehelper_setup() + call_usermodehelper_exec() instead of
calling call_usermodehelper_fns(). In case the latter returns -ENOMEM the
cleanup function may had not been called - in this case we would not free
argv and module_name.Signed-off-by: Lucas De Marchi
Cc: Oleg Nesterov
Cc: David Howells
Cc: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
call_usermodehelper_setup() + call_usermodehelper_exec() need to be
called instead of call_usermodehelper_fns() when the cleanup function
needs to be called even when an ENOMEM error occurs. In this case using
call_usermodehelper_fns() the user can't distinguish if the cleanup
function was called or not.[akpm@linux-foundation.org: export call_usermodehelper_setup() to modules]
Signed-off-by: Lucas De Marchi
Reviewed-by: Oleg Nesterov
Cc: David Howells
Cc: James Morris
Cc: Al Viro
Cc: Tejun Heo
Cc: "Rafael J. Wysocki"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
* Dump signals from process-wide and per-thread queues with
different sizes of buffers.
* Check error paths for buffers with restricted permissions. A part of
buffer or a whole buffer is for read-only.
* Try to get nonexistent signal.Signed-off-by: Andrew Vagin
Cc: Roland McGrath
Cc: Oleg Nesterov
Cc: "Paul E. McKenney"
Cc: David Howells
Cc: Dave Jones
Cc: "Michael Kerrisk (man-pages)"
Cc: Pavel Emelyanov
Cc: Linus Torvalds
Cc: Pedro Alves
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch adds a new ptrace request PTRACE_PEEKSIGINFO.
This request is used to retrieve information about pending signals
starting with the specified sequence number. Siginfo_t structures are
copied from the child into the buffer starting at "data".The argument "addr" is a pointer to struct ptrace_peeksiginfo_args.
struct ptrace_peeksiginfo_args {
u64 off; /* from which siginfo to start */
u32 flags;
s32 nr; /* how may siginfos to take */
};"nr" has type "s32", because ptrace() returns "long", which has 32 bits on
i386 and a negative values is used for errors.Currently here is only one flag PTRACE_PEEKSIGINFO_SHARED for dumping
signals from process-wide queue. If this flag is not set, signals are
read from a per-thread queue.The request PTRACE_PEEKSIGINFO returns a number of dumped signals. If a
signal with the specified sequence number doesn't exist, ptrace returns
zero. The request returns an error, if no signal has been dumped.Errors:
EINVAL - one or more specified flags are not supported or nr is negative
EFAULT - buf or addr is outside your accessible address space.A result siginfo contains a kernel part of si_code which usually striped,
but it's required for queuing the same siginfo back during restore of
pending signals.This functionality is required for checkpointing pending signals. Pedro
Alves suggested using it in "gdb" to peek at pending signals. gdb already
uses PTRACE_GETSIGINFO to get the siginfo for the signal which was already
dequeued. This functionality allows gdb to look at the pending signals
which were not reported yet.The prototype of this code was developed by Oleg Nesterov.
Signed-off-by: Andrew Vagin
Cc: Roland McGrath
Cc: Oleg Nesterov
Cc: "Paul E. McKenney"
Cc: David Howells
Cc: Dave Jones
Cc: "Michael Kerrisk (man-pages)"
Cc: Pavel Emelyanov
Cc: Linus Torvalds
Cc: Pedro Alves
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Vyacheslav Dubeyko
Cc: Christoph Hellwig
Cc: Al Viro
Cc: Hin-Tak Leung
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
__hfsplus_ext_write_extent() suppresses errors coming from
hfs_brec_find(). The patch implements error code propagation.Signed-off-by: Alexey Khoroshilov
Reviewed-by: Vyacheslav Dubeyko
Cc: Hin-Tak Leung
Cc: Al Viro
Cc: Artem Bityutskiy
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use a more current logging style.
Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
hfsplus now uses "hfsplus: " for all messages.
Coalesce formats.
Prefix debugging messages too.Signed-off-by: Joe Perches
Cc: Vyacheslav Dubeyko
Cc: Hin-Tak Leung
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use a more current logging style.
Rename macro and uses.
Add do {} while (0) to macro.
Add DBG_ to macro.
Add and use hfs_dbg_cont variant where appropriate.Signed-off-by: Joe Perches
Cc: Vyacheslav Dubeyko
Cc: Hin-Tak Leung
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
fs/hfsplus/bfind.c: In function 'hfs_find_1st_rec_by_cnid':
(1) include/uapi/linux/swab.h:60:2: warning: 'search_cnid' may be used uninitialized in this function [-Wmaybe-uninitialized]
(2) include/uapi/linux/swab.h:60:2: warning: 'cur_cnid' may be used uninitialized in this function [-Wmaybe-uninitialized][akpm@linux-foundation.org: make the workaround more explicit]
Signed-off-by: Vyacheslav Dubeyko
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
hfs_find_init() may fail with ENOMEM, but there are places, where the
returned value is not checked. The consequences can be very unpleasant,
e.g. kfree uninitialized pointer and inappropriate mutex unlocking.The patch adds checks for errors in hfs_find_init().
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov
Reviewed-by: Vyacheslav Dubeyko
Cc: Hin-Tak Leung
Cc: Al Viro
Cc: Artem Bityutskiy
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
page->mapping->host cannot be NULL in nilfs_writepage(), so remove the
unneeded test.The fixes the smatch warning: "fs/nilfs2/inode.c:211 nilfs_writepage()
error: we previously assumed 'inode' could be null (see line 195)".Reported-by: Dan Carpenter
Signed-off-by: Vyacheslav Dubeyko
Cc: Ryusuke Konishi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Change test_bit(PG_locked, &page->flags) to PageLocked().
Signed-off-by: Vyacheslav Dubeyko
Cc: Ryusuke Konishi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
…river's internal error or metadata corruption
The NILFS2 driver remounts itself in RO mode in the case of discovering
metadata corruption (for example, discovering a broken bmap). But
usually, this takes place when there have been file system operations
before remounting in RO mode.Thereby, NILFS2 driver can be in RO mode with presence of dirty pages in
modified inodes' address spaces. It results in flush kernel thread's
infinite trying to flush dirty pages in RO mode. As a result, it is
possible to see such side effects as: (1) flush kernel thread occupies
50% - 99% of CPU time; (2) system can't be shutdowned without manual
power switch off.SYMPTOMS:
(1) System log contains error message: "Remounting filesystem read-only".
(2) The flush kernel thread occupies 50% - 99% of CPU time.
(3) The system can't be shutdowned without manual power switch off.REPRODUCTION PATH:
(1) Create volume group with name "unencrypted" by means of vgcreate utility.
(2) Run script (prepared by Anthony Doggett <Anthony2486@interfaces.org.uk>):----------------[BEGIN SCRIPT]--------------------
#!/bin/bashVG=unencrypted
#apt-get install nilfs-tools darcs
lvcreate --size 2G --name ntest $VG
mkfs.nilfs2 -b 1024 -B 8192 /dev/mapper/$VG-ntest
mkdir /var/tmp/n
mkdir /var/tmp/n/ntest
mount /dev/mapper/$VG-ntest /var/tmp/n/ntest
mkdir /var/tmp/n/ntest/thedir
cd /var/tmp/n/ntest/thedir
sleep 2
date
darcs init
sleep 2
dmesg|tail -n 5
date
darcs whatsnew || true
date
sleep 2
dmesg|tail -n 5
----------------[END SCRIPT]--------------------(3) Try to shutdown the system.
REPRODUCIBILITY: 100%
FIX:
This patch implements checking mount state of NILFS2 driver in
nilfs_writepage(), nilfs_writepages() and nilfs_mdt_write_page()
methods. If it is detected the RO mount state then all dirty pages are
simply discarded with warning messages is written in system log.[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Anthony Doggett <Anthony2486@interfaces.org.uk>
Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp>
Cc: Piotr Szymaniak <szarpaj@grubelek.pl>
Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com>
Cc: Elmer Zhang <freeboy6716@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> -
Limit the size of the copy so we don't corrupt memory. Hopefully this
can only be called by root, but fixing this makes the static checkers
happier.Signed-off-by: Dan Carpenter
Cc: Jiri Kosina
Cc: Masanari Iida
Cc: Alan Cox
Cc: Guenter Roeck
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the calls to memcpy_fromio() up into the loop in
dmi_scan_machine(), and move the signature checks back down into
dmi_decode(). We need to check at 16-byte intervals but keep a 32-byte
buffer for an SMBIOS entry, so shift the buffer after each iteration.Merge smbios_present() into dmi_present(), so we look for an SMBIOS
signature at the beginning of the given buffer and then for a DMI
signature at an offset of 16 bytes.[artem.savkov@gmail.com: use proper buf type in dmi_present()]
Signed-off-by: Ben Hutchings
Reported-by: Tim McGrath
Tested-by: Tim Mcgrath
Cc: Zhenzhong Duan
Signed-off-by: Artem Savkov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The comment I originally added in commit a3defbe5c337 ("binfmt_elf: fix
PIE execution with randomization disabled") is not really 100% accurate
-- sysctl is not the only way how PF_RANDOMIZE could be forcibly unset
in runtime.Another option of course is direct modification of personality flags
(i.e. running through setarch wrapper).Make the comment more explicit and accurate.
Signed-off-by: Jiri Kosina
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add a new configuration option CONFIG_BINFMT_SCRIPT to configure support
for interpreted scripts starting with "#!"; allow compiling out that
support, or building it as a module. Embedded systems running exclusively
compiled binaries could leave this support out, and systems that don't
need scripts before mounting the root filesystem can build this as a
module.Signed-off-by: Josh Triplett
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is always safe to use RCU_INIT_POINTER to NULL a pointer. This results
in slightly smaller/faster code.Signed-off-by: Eric Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This reduces the amount of code inside the ready list iteration loops for
better readability IMHO.Signed-off-by: Eric Wong
Cc: Davide Libenzi
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Technically we do not need to hold ep->mtx during ep_free since we are
certain there are no other users of ep at that point. However, lockdep
complains with a "suspicious rcu_dereference_check() usage!" message; so
lock the mutex before ep_remove to silence the warning.Signed-off-by: Eric Wong
Cc: Al Viro
Cc: Arve Hjønnevåg
Cc: Davide Libenzi
Cc: Eric Dumazet
Cc: NeilBrown ,
Cc: Rafael J. Wysocki
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This prevents wakeup_source destruction when a user hits the item with
EPOLL_CTL_MOD while ep_poll_callback is running.Tested with CONFIG_SPARSE_RCU_POINTER=y and "make fs/eventpoll.o C=2"
Signed-off-by: Eric Wong
Cc: Alexander Viro
Cc: Arve Hjønnevåg
Cc: Davide Libenzi
Cc: Eric Dumazet
Cc: NeilBrown
Cc: "Rafael J. Wysocki"
Cc: "Paul E. McKenney"
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is common for epoll users to have thousands of epitems, so saving a
cache line on every allocation leads to large memory savings.Since epitem allocations are cache-aligned, reducing sizeof(struct
epitem) from 136 bytes to 128 bytes will allow it to squeeze under a
cache line boundary on x86_64.Via /sys/kernel/slab/eventpoll_epi, I see the following changes on my
x86_64 Core2 Duo (which has 64-byte cache alignment):object_size : 192 => 128
objs_per_slab: 21 => 32Also, add a BUILD_BUG_ON() to check for future accidental breakage.
[akpm@linux-foundation.org: use __packed, for all architectures]
Signed-off-by: Eric Wong
Cc: Davide Libenzi
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Andrew Morton noted:
akpm3:/usr/src/25> grep SYSCALL kernel/timer.c
SYSCALL_DEFINE1(alarm, unsigned int, seconds)
SYSCALL_DEFINE0(getpid)
SYSCALL_DEFINE0(getppid)
SYSCALL_DEFINE0(getuid)
SYSCALL_DEFINE0(geteuid)
SYSCALL_DEFINE0(getgid)
SYSCALL_DEFINE0(getegid)
SYSCALL_DEFINE0(gettid)
SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)Only one of those should be in kernel/timer.c. Who wrote this thing?
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stephen Rothwell
Acked-by: Thomas Gleixner
Cc: Guenter Roeck
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Stephen Rothwell
Cc: Thomas Gleixner
Cc: Guenter Roeck
Cc: Al Viro
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The only use outside of kernel/timer.c was in kernel/compat.c, so move
compat_sys_sysinfo() next to sys_sysinfo() in kernel/timer.c.Signed-off-by: Stephen Rothwell
Cc: Thomas Gleixner
Cc: Guenter Roeck
Cc: Al Viro
Acked-by: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
