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Date: Sat, 02 Jan 2010 15:05:09 +0100
From: Stefani Seibold <stefani@...bold.net>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Samuel Thibault <samuel.thibault@...-lyon.org>,
Ingo Molnar <mingo@...e.hu>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Alexey Dobriyan <adobriyan@...il.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Subject: [PATCH] partial revert to show stack information in
/proc/<pid>/status
As announce here is the patch to partial revert the show stack
information patch due a not accepted performance regression. It will be
now show only the current stack usage, not the high water mark.
The path is only partial reverted because i need the other parts to do
it in an other way.
There are now two possibilities solutions:
- create a new /proc/<pid>/stackinfo entry, which provides the reverted
information and maybe others like the sigaltstack.
- create a user space tool which use /proc/<pid>/pagemap
In both cases the information of task->stack_start and the KSTK_ESP is
needed.
It will be also needed for an enhancement of the oom handler, where i
free unused stack pages (the pages before the stack pointer) under high
memory pressure. This is currently under work.
Andrew please apply this patch to 2.6.34-rc* tree.
Greetings,
Stefani
Signed-off-by: Stefani Seibold <stefani@...bold.net>
---
Documentation/filesystems/proc.txt | 2
fs/proc/array.c | 87 ++-----------------------------------
2 files changed, 8 insertions(+), 81 deletions(-)
diff -u -N -r -p linux-2.6.33-rc2.orig/fs/proc/array.c linux-2.6.33-rc2.new/fs/proc/array.c
--- linux-2.6.33-rc2.orig/fs/proc/array.c 2009-12-27 23:37:04.817427024 +0100
+++ linux-2.6.33-rc2.new/fs/proc/array.c 2010-01-02 14:36:53.794188418 +0100
@@ -327,93 +327,20 @@ static inline void task_context_switch_c
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)
+static inline void task_show_stack_usage(struct seq_file *m,
+ struct task_struct *task)
{
- 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;
+ unsigned long usage;
+ if (task->mm) {
#ifdef CONFIG_STACK_GROWSUP
- if (pte_present(ptent) || is_swap_pte(ptent))
- ss->usage = addr - ss->startpage + PAGE_SIZE;
+ usage = KSTK_ESP(task) - task->stack_start;
#else
- if (pte_present(ptent) || is_swap_pte(ptent)) {
- ss->usage = ss->startpage - addr + PAGE_SIZE;
- pte++;
- ret = 1;
- break;
- }
+ usage = task->stack_start - KSTK_ESP(task);
#endif
+ seq_printf(m, "Stack usage:\t%lu kB\n", (usage + 1023) >> 10);
}
- 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)
{
diff -u -N -r -p linux-2.6.33-rc2.orig/Documentation/filesystems/proc.txt linux-2.6.33-rc2.new/Documentation/filesystems/proc.txt
--- linux-2.6.33-rc2.orig/Documentation/filesystems/proc.txt 2009-12-27 23:37:01.098310709 +0100
+++ linux-2.6.33-rc2.new/Documentation/filesystems/proc.txt 2010-01-02 14:30:39.059150340 +0100
@@ -231,7 +231,7 @@ Table 1-2: Contents of the statm files (
Mems_allowed_list Same as previous, but in "list format"
voluntary_ctxt_switches number of voluntary context switches
nonvoluntary_ctxt_switches number of non voluntary context switches
- Stack usage: stack usage high water mark (round up to page size)
+ Stack usage: stack usage in kB
..............................................................................
Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
--
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