Johannes Weiner 65376df582 proc: revert /proc/<pid>/maps [stack:TID] annotation ... Commit b76437579d ("procfs: mark thread stack correctly in proc/<pid>/maps") added [stack:TID] annotation to /proc/<pid>/maps. Finding the task of a stack VMA requires walking the entire thread list, turning this into quadratic behavior: a thousand threads means a thousand stacks, so the rendering of /proc/<pid>/maps needs to look at a million combinations. The cost is not in proportion to the usefulness as described in the patch. Drop the [stack:TID] annotation to make /proc/<pid>/maps (and /proc/<pid>/numa_maps) usable again for higher thread counts. The [stack] annotation inside /proc/<pid>/task/<tid>/maps is retained, as identifying the stack VMA there is an O(1) operation. Siddesh said: "The end users needed a way to identify thread stacks programmatically and there wasn't a way to do that. I'm afraid I no longer remember (or have access to the resources that would aid my memory since I changed employers) the details of their requirement. However, I did do this on my own time because I thought it was an interesting project for me and nobody really gave any feedback then as to its utility, so as far as I am concerned you could roll back the main thread maps information since the information is available in the thread-specific files" Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com> Cc: Shaohua Li <shli@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-02-03 08:28:43 -08:00
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array.c
base.c	proc read mm's {arg,env}_{start,end} with mmap semaphore taken.	2016-01-20 17:09:18 -08:00
cmdline.c
consoles.c
cpuinfo.c
devices.c
fd.c
fd.h
generic.c
inode.c
internal.h
interrupts.c
Kconfig
kcore.c	wrappers for ->i_mutex access	2016-01-22 18:04:28 -05:00
kmsg.c
loadavg.c
Makefile
meminfo.c
namespaces.c
nommu.c
page.c
proc_net.c
proc_sysctl.c
proc_tty.c
root.c
self.c	wrappers for ->i_mutex access	2016-01-22 18:04:28 -05:00
softirqs.c
stat.c
task_mmu.c	proc: revert /proc/<pid>/maps [stack:TID] annotation	2016-02-03 08:28:43 -08:00
task_nommu.c	proc: revert /proc/<pid>/maps [stack:TID] annotation	2016-02-03 08:28:43 -08:00
thread_self.c	wrappers for ->i_mutex access	2016-01-22 18:04:28 -05:00
uptime.c
version.c
vmcore.c