procfs: mark thread stack correctly in proc/<pid>/maps

[deliverable/linux.git] / Documentation / filesystems / proc.txt

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a76a26a1db8a6fe855b0eeea32dee251296c0c8a..b7413cb46dcb1f1a331068861e766a6c03a5da40 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -290,7 +290,7 @@ Table 1-4: Contents of the stat files (as of 2.6.30-rc7)
   rsslim        current limit in bytes on the rss
   start_code    address above which program text can run
   end_code      address below which program text can run
-  start_stack   address of the start of the stack
+  start_stack   address of the start of the main process stack
   esp           current value of ESP
   eip           current value of EIP
   pending       bitmap of pending signals
@@ -325,7 +325,7 @@ address           perms offset  dev   inode      pathname
 a7cb1000-a7cb2000 ---p 00000000 00:00 0
 a7cb2000-a7eb2000 rw-p 00000000 00:00 0
 a7eb2000-a7eb3000 ---p 00000000 00:00 0
-a7eb3000-a7ed5000 rw-p 00000000 00:00 0
+a7eb3000-a7ed5000 rw-p 00000000 00:00 0          [stack:1001]
 a7ed5000-a8008000 r-xp 00000000 03:00 4222       /lib/libc.so.6
 a8008000-a800a000 r--p 00133000 03:00 4222       /lib/libc.so.6
 a800a000-a800b000 rw-p 00135000 03:00 4222       /lib/libc.so.6
@@ -357,11 +357,39 @@ is not associated with a file:
 
  [heap]                   = the heap of the program
  [stack]                  = the stack of the main process
+ [stack:1001]             = the stack of the thread with tid 1001
  [vdso]                   = the "virtual dynamic shared object",
                             the kernel system call handler
 
  or if empty, the mapping is anonymous.
 
+The /proc/PID/task/TID/maps is a view of the virtual memory from the viewpoint
+of the individual tasks of a process. In this file you will see a mapping marked
+as [stack] if that task sees it as a stack. This is a key difference from the
+content of /proc/PID/maps, where you will see all mappings that are being used
+as stack by all of those tasks. Hence, for the example above, the task-level
+map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this:
+
+08048000-08049000 r-xp 00000000 03:00 8312       /opt/test
+08049000-0804a000 rw-p 00001000 03:00 8312       /opt/test
+0804a000-0806b000 rw-p 00000000 00:00 0          [heap]
+a7cb1000-a7cb2000 ---p 00000000 00:00 0
+a7cb2000-a7eb2000 rw-p 00000000 00:00 0
+a7eb2000-a7eb3000 ---p 00000000 00:00 0
+a7eb3000-a7ed5000 rw-p 00000000 00:00 0          [stack]
+a7ed5000-a8008000 r-xp 00000000 03:00 4222       /lib/libc.so.6
+a8008000-a800a000 r--p 00133000 03:00 4222       /lib/libc.so.6
+a800a000-a800b000 rw-p 00135000 03:00 4222       /lib/libc.so.6
+a800b000-a800e000 rw-p 00000000 00:00 0
+a800e000-a8022000 r-xp 00000000 03:00 14462      /lib/libpthread.so.0
+a8022000-a8023000 r--p 00013000 03:00 14462      /lib/libpthread.so.0
+a8023000-a8024000 rw-p 00014000 03:00 14462      /lib/libpthread.so.0
+a8024000-a8027000 rw-p 00000000 00:00 0
+a8027000-a8043000 r-xp 00000000 03:00 8317       /lib/ld-linux.so.2
+a8043000-a8044000 r--p 0001b000 03:00 8317       /lib/ld-linux.so.2
+a8044000-a8045000 rw-p 0001c000 03:00 8317       /lib/ld-linux.so.2
+aff35000-aff4a000 rw-p 00000000 00:00 0
+ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]
 
 The /proc/PID/smaps is an extension based on maps, showing the memory
 consumption for each of the process's mappings. For each of mappings there