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authorStefani Seibold <stefani@seibold.net>2009-09-22 19:45:40 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 10:39:41 -0400
commitd899bf7b55f503ba7d3d07ed27c3a37e270fa7db (patch)
tree32a5ee7816b2f0cb3261dcca8102b9cafe9251bd /Documentation
parentcba8aafe1e07dfc8bae5ba78be8e02883bd34d31 (diff)
procfs: provide stack information for threads
A patch to give a better overview of the userland application stack usage, especially for embedded linux. Currently you are only able to dump the main process/thread stack usage which is showed in /proc/pid/status by the "VmStk" Value. But you get no information about the consumed stack memory of the the threads. There is an enhancement in the /proc/<pid>/{task/*,}/*maps and which marks the vm mapping where the thread stack pointer reside with "[thread stack xxxxxxxx]". xxxxxxxx is the maximum size of stack. This is a value information, because libpthread doesn't set the start of the stack to the top of the mapped area, depending of the pthread usage. A sample output of /proc/<pid>/task/<tid>/maps looks like: 08048000-08049000 r-xp 00000000 03:00 8312 /opt/z 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/z 0804a000-0806b000 rw-p 00000000 00:00 0 [heap] a7d12000-a7d13000 ---p 00000000 00:00 0 a7d13000-a7f13000 rw-p 00000000 00:00 0 [thread stack: 001ff4b4] a7f13000-a7f14000 ---p 00000000 00:00 0 a7f14000-a7f36000 rw-p 00000000 00:00 0 a7f36000-a8069000 r-xp 00000000 03:00 4222 /lib/libc.so.6 a8069000-a806b000 r--p 00133000 03:00 4222 /lib/libc.so.6 a806b000-a806c000 rw-p 00135000 03:00 4222 /lib/libc.so.6 a806c000-a806f000 rw-p 00000000 00:00 0 a806f000-a8083000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0 a8083000-a8084000 r--p 00013000 03:00 14462 /lib/libpthread.so.0 a8084000-a8085000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0 a8085000-a8088000 rw-p 00000000 00:00 0 a8088000-a80a4000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2 a80a4000-a80a5000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2 a80a5000-a80a6000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2 afaf5000-afb0a000 rw-p 00000000 00:00 0 [stack] ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] Also there is a new entry "stack usage" in /proc/<pid>/{task/*,}/status which will you give the current stack usage in kb. A sample output of /proc/self/status looks like: Name: cat State: R (running) Tgid: 507 Pid: 507 . . . CapBnd: fffffffffffffeff voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 0 Stack usage: 12 kB I also fixed stack base address in /proc/<pid>/{task/*,}/stat to the base address of the associated thread stack and not the one of the main process. This makes more sense. [akpm@linux-foundation.org: fs/proc/array.c now needs walk_page_range()] Signed-off-by: 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/proc.txt5
1 files changed, 4 insertions, 1 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 75988ba26a51..b5aee7838a00 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -176,6 +176,7 @@ read the file /proc/PID/status:
176 CapBnd: ffffffffffffffff 176 CapBnd: ffffffffffffffff
177 voluntary_ctxt_switches: 0 177 voluntary_ctxt_switches: 0
178 nonvoluntary_ctxt_switches: 1 178 nonvoluntary_ctxt_switches: 1
179 Stack usage: 12 kB
179 180
180This shows you nearly the same information you would get if you viewed it with 181This shows you nearly the same information you would get if you viewed it with
181the ps command. In fact, ps uses the proc file system to obtain its 182the ps command. In fact, ps uses the proc file system to obtain its
@@ -229,6 +230,7 @@ Table 1-2: Contents of the statm files (as of 2.6.30-rc7)
229 Mems_allowed_list Same as previous, but in "list format" 230 Mems_allowed_list Same as previous, but in "list format"
230 voluntary_ctxt_switches number of voluntary context switches 231 voluntary_ctxt_switches number of voluntary context switches
231 nonvoluntary_ctxt_switches number of non voluntary context switches 232 nonvoluntary_ctxt_switches number of non voluntary context switches
233 Stack usage: stack usage high water mark (round up to page size)
232.............................................................................. 234..............................................................................
233 235
234Table 1-3: Contents of the statm files (as of 2.6.8-rc3) 236Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
@@ -307,7 +309,7 @@ address perms offset dev inode pathname
30708049000-0804a000 rw-p 00001000 03:00 8312 /opt/test 30908049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
3080804a000-0806b000 rw-p 00000000 00:00 0 [heap] 3100804a000-0806b000 rw-p 00000000 00:00 0 [heap]
309a7cb1000-a7cb2000 ---p 00000000 00:00 0 311a7cb1000-a7cb2000 ---p 00000000 00:00 0
310a7cb2000-a7eb2000 rw-p 00000000 00:00 0 312a7cb2000-a7eb2000 rw-p 00000000 00:00 0 [threadstack:001ff4b4]
311a7eb2000-a7eb3000 ---p 00000000 00:00 0 313a7eb2000-a7eb3000 ---p 00000000 00:00 0
312a7eb3000-a7ed5000 rw-p 00000000 00:00 0 314a7eb3000-a7ed5000 rw-p 00000000 00:00 0
313a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6 315a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
@@ -343,6 +345,7 @@ is not associated with a file:
343 [stack] = the stack of the main process 345 [stack] = the stack of the main process
344 [vdso] = the "virtual dynamic shared object", 346 [vdso] = the "virtual dynamic shared object",
345 the kernel system call handler 347 the kernel system call handler
348 [threadstack:xxxxxxxx] = the stack of the thread, xxxxxxxx is the stack size
346 349
347 or if empty, the mapping is anonymous. 350 or if empty, the mapping is anonymous.
348 351