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author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-01-08 23:42:56 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-01-11 18:34:06 +0100 |
commit | 1306d603fcf1f6682f8575d1ff23631a24184b21 (patch) | |
tree | 8e2278cfabf874cb16bf03bd182ae75b87055741 /fs/proc/array.c | |
parent | .gitignore: ignore vmlinuz (diff) | |
download | linux-1306d603fcf1f6682f8575d1ff23631a24184b21.tar.xz linux-1306d603fcf1f6682f8575d1ff23631a24184b21.zip |
proc: partially revert "procfs: provide stack information for threads"
Commit d899bf7b (procfs: provide stack information for threads) introduced
to show stack information in /proc/{pid}/status. But it cause large
performance regression. Unfortunately /proc/{pid}/status is used ps
command too and ps is one of most important component. Because both to
take mmap_sem and page table walk are heavily operation.
If many process run, the ps performance is,
[before d899bf7b]
% perf stat ps >/dev/null
Performance counter stats for 'ps':
4090.435806 task-clock-msecs # 0.032 CPUs
229 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
234 page-faults # 0.000 M/sec
8587565207 cycles # 2099.425 M/sec
9866662403 instructions # 1.149 IPC
3789415411 cache-references # 926.409 M/sec
30419509 cache-misses # 7.437 M/sec
128.859521955 seconds time elapsed
[after d899bf7b]
% perf stat ps > /dev/null
Performance counter stats for 'ps':
4305.081146 task-clock-msecs # 0.028 CPUs
480 context-switches # 0.000 M/sec
2 CPU-migrations # 0.000 M/sec
237 page-faults # 0.000 M/sec
9021211334 cycles # 2095.480 M/sec
10605887536 instructions # 1.176 IPC
3612650999 cache-references # 839.160 M/sec
23917502 cache-misses # 5.556 M/sec
152.277819582 seconds time elapsed
Thus, this patch revert it. Fortunately /proc/{pid}/task/{tid}/smaps
provide almost same information. we can use it.
Commit d899bf7b introduced two features:
1) Add the annotattion of [thread stack: xxxx] mark to
/proc/{pid}/task/{tid}/maps.
2) Add StackUsage field to /proc/{pid}/status.
I only revert (2), because I haven't seen (1) cause regression.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: 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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
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 | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index f560325c444f..13b5d0708175 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -327,94 +327,6 @@ static inline void task_context_switch_counts(struct seq_file *m, p->nivcsw); } -#ifdef CONFIG_MMU - -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); - } -} -#else -static void task_show_stack_usage(struct seq_file *m, struct task_struct *task) -{ -} -#endif /* CONFIG_MMU */ - static void task_cpus_allowed(struct seq_file *m, struct task_struct *task) { seq_printf(m, "Cpus_allowed:\t"); @@ -445,7 +357,6 @@ 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; } |