diff options
author | Stefani Seibold <stefani@seibold.net> | 2009-09-22 16:45:40 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 07:39:41 -0700 |
commit | d899bf7b55f503ba7d3d07ed27c3a37e270fa7db (patch) | |
tree | 32a5ee7816b2f0cb3261dcca8102b9cafe9251bd /fs/proc/array.c | |
parent | cba8aafe1e07dfc8bae5ba78be8e02883bd34d31 (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 'fs/proc/array.c')
-rw-r--r-- | fs/proc/array.c | 85 |
1 files changed, 84 insertions, 1 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 725a650bbbb8..0c6bc602e6c4 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -82,6 +82,7 @@ #include <linux/pid_namespace.h> #include <linux/ptrace.h> #include <linux/tracehook.h> +#include <linux/swapops.h> #include <asm/pgtable.h> #include <asm/processor.h> @@ -321,6 +322,87 @@ static inline void task_context_switch_counts(struct seq_file *m, p->nivcsw); } +struct stack_stats { + struct vm_area_struct *vma; + unsigned long startpage; + unsigned long usage; +}; + +static int stack_usage_pte_range(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct stack_stats *ss = walk->private; + struct vm_area_struct *vma = ss->vma; + pte_t *pte, ptent; + spinlock_t *ptl; + int ret = 0; + + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (; addr != end; pte++, addr += PAGE_SIZE) { + ptent = *pte; + +#ifdef CONFIG_STACK_GROWSUP + if (pte_present(ptent) || is_swap_pte(ptent)) + ss->usage = addr - ss->startpage + PAGE_SIZE; +#else + if (pte_present(ptent) || is_swap_pte(ptent)) { + ss->usage = ss->startpage - addr + PAGE_SIZE; + pte++; + ret = 1; + break; + } +#endif + } + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); + return ret; +} + +static inline unsigned long get_stack_usage_in_bytes(struct vm_area_struct *vma, + struct task_struct *task) +{ + struct stack_stats ss; + struct mm_walk stack_walk = { + .pmd_entry = stack_usage_pte_range, + .mm = vma->vm_mm, + .private = &ss, + }; + + if (!vma->vm_mm || is_vm_hugetlb_page(vma)) + return 0; + + ss.vma = vma; + ss.startpage = task->stack_start & PAGE_MASK; + ss.usage = 0; + +#ifdef CONFIG_STACK_GROWSUP + walk_page_range(KSTK_ESP(task) & PAGE_MASK, vma->vm_end, + &stack_walk); +#else + walk_page_range(vma->vm_start, (KSTK_ESP(task) & PAGE_MASK) + PAGE_SIZE, + &stack_walk); +#endif + return ss.usage; +} + +static inline void task_show_stack_usage(struct seq_file *m, + struct task_struct *task) +{ + struct vm_area_struct *vma; + struct mm_struct *mm = get_task_mm(task); + + if (mm) { + down_read(&mm->mmap_sem); + vma = find_vma(mm, task->stack_start); + if (vma) + seq_printf(m, "Stack usage:\t%lu kB\n", + get_stack_usage_in_bytes(vma, task) >> 10); + + up_read(&mm->mmap_sem); + mmput(mm); + } +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -340,6 +422,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, task_show_regs(m, task); #endif task_context_switch_counts(m, task); + task_show_stack_usage(m, task); return 0; } @@ -481,7 +564,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, rsslim, mm ? mm->start_code : 0, mm ? mm->end_code : 0, - (permitted && mm) ? mm->start_stack : 0, + (permitted) ? task->stack_start : 0, esp, eip, /* The signal information here is obsolete. |