From d899bf7b55f503ba7d3d07ed27c3a37e270fa7db Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Tue, 22 Sep 2009 16:45:40 -0700 Subject: 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//{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//task//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//{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//{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 Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alexey Dobriyan Cc: "Eric W. Biederman" Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/array.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 84 insertions(+), 1 deletion(-) (limited to 'fs/proc/array.c') 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 #include #include +#include #include #include @@ -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. -- cgit v1.2.3