Commit d899bf7b (procfs: provide stack information for threads) introduced
to show stack information in /proc/{pid}/status. But it cause large
performance regression. Unfortunately /proc/{pid}/status is used ps
command too and ps is one of most important component. Because both to
take mmap_sem and page table walk are heavily operation.
If many process run, the ps performance is,
[before d899bf7b]
% perf stat ps >/dev/null
Performance counter stats for 'ps':
4090.435806 task-clock-msecs # 0.032 CPUs
229 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
234 page-faults # 0.000 M/sec
8587565207 cycles # 2099.425 M/sec
9866662403 instructions # 1.149 IPC
3789415411 cache-references # 926.409 M/sec
30419509 cache-misses # 7.437 M/sec
128.859521955 seconds time elapsed
[after d899bf7b]
% perf stat ps > /dev/null
Performance counter stats for 'ps':
4305.081146 task-clock-msecs # 0.028 CPUs
480 context-switches # 0.000 M/sec
2 CPU-migrations # 0.000 M/sec
237 page-faults # 0.000 M/sec
9021211334 cycles # 2095.480 M/sec
10605887536 instructions # 1.176 IPC
3612650999 cache-references # 839.160 M/sec
23917502 cache-misses # 5.556 M/sec
152.277819582 seconds time elapsed
Thus, this patch revert it. Fortunately /proc/{pid}/task/{tid}/smaps
provide almost same information. we can use it.
Commit d899bf7b introduced two features:
1) Add the annotattion of [thread stack: xxxx] mark to
/proc/{pid}/task/{tid}/maps.
2) Add StackUsage field to /proc/{pid}/status.
I only revert (2), because I haven't seen (1) cause regression.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2: nilfs2: update mailing list address nilfs2: Storage class should be before const qualifier nilfs2: trivial coding style fix
This replaces the list address for nilfs discussion to linux-nilfs at vger.kernel.org from users at nilfs.org. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Per commit 240799cd, the option name for readahead should be inode_readahead_blks, not inode_readahead. Signed-off-by: Fang Wenqi <antonf@turbolinux.com.cn> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Many struct driver_attribute descriptors are purely read-only structures, and there's no need to change them. Therefore make the promise not to, which will let those descriptors be put in a ro section. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Most device_attributes are const, and are begging to be put in a ro section. However, the create and remove file interfaces were failing to propagate the const promise which the only functions they call offer. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-2.6.33' of git://linux-nfs.org/~bfields/linux: (42 commits) nfsd: remove pointless paths in file headers nfsd: move most of nfsfh.h to fs/nfsd nfsd: remove unused field rq_reffh nfsd: enable V4ROOT exports nfsd: make V4ROOT exports read-only nfsd: restrict filehandles accepted in V4ROOT case nfsd: allow exports of symlinks nfsd: filter readdir results in V4ROOT case nfsd: filter lookup results in V4ROOT case nfsd4: don't continue "under" mounts in V4ROOT case nfsd: introduce export flag for v4 pseudoroot nfsd: let "insecure" flag vary by pseudoflavor nfsd: new interface to advertise export features nfsd: Move private headers to source directory vfs: nfsctl.c un-used nfsd #includes lockd: Remove un-used nfsd headers #includes s390: remove un-used nfsd #includes sparc: remove un-used nfsd #includes parsic: remove un-used nfsd #includes compat.c: Remove dependence on nfsd private headers ...
Using create_proc_entry() + ->proc_fops assignment is racy because ->proc_fops will be NULL for some time, use proc_create() to avoid race. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Setting a thread's comm to be something unique is a very useful ability and is helpful for debugging complicated threaded applications. However currently the only way to set a thread name is for the thread to name itself via the PR_SET_NAME prctl. However, there may be situations where it would be advantageous for a thread dispatcher to be naming the threads its managing, rather then having the threads self-describe themselves. This sort of behavior is available on other systems via the pthread_setname_np() interface. This patch exports a task's comm via proc/pid/comm and proc/pid/task/tid/comm interfaces, and allows thread siblings to write to these values. [akpm@linux-foundation.org: cleanups] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Mike Fulton <fultonm@ca.ibm.com> Cc: Sean Foley <Sean_Foley@ca.ibm.com> Cc: Darren Hart <dvhltc@us.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6: (21 commits) ext3: PTR_ERR return of wrong pointer in setup_new_group_blocks() ext3: Fix data / filesystem corruption when write fails to copy data ext4: Support for 64-bit quota format ext3: Support for vfsv1 quota format quota: Implement quota format with 64-bit space and inode limits quota: Move definition of QFMT_OCFS2 to linux/quota.h ext2: fix comment in ext2_find_entry about return values ext3: Unify log messages in ext3 ext2: clear uptodate flag on super block I/O error ext2: Unify log messages in ext2 ext3: make "norecovery" an alias for "noload" ext3: Don't update the superblock in ext3_statfs() ext3: journal all modifications in ext3_xattr_set_handle ext2: Explicitly assign values to on-disk enum of filetypes quota: Fix WARN_ON in lookup_one_len const: struct quota_format_ops ubifs: remove manual O_SYNC handling afs: remove manual O_SYNC handling kill wait_on_page_writeback_range vfs: Implement proper O_SYNC semantics ...