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| author | Petr Cermak <petrcermak@chromium.org> | 2015-02-12 15:01:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 18:54:12 -0800 |
| commit | 695f055936938c674473ea071ca7359a863551e7 (patch) | |
| tree | 8975abce255f8d638fa1291beb62803e2d611004 | |
| parent | d170cf4674768db22b66a1be4be7877d3b2c3874 (diff) | |
| download | lwn-695f055936938c674473ea071ca7359a863551e7.tar.gz lwn-695f055936938c674473ea071ca7359a863551e7.zip | |
fs/proc/task_mmu.c: add user-space support for resetting mm->hiwater_rss (peak RSS)
Peak resident size of a process can be reset back to the process's
current rss value by writing "5" to /proc/pid/clear_refs. The driving
use-case for this would be getting the peak RSS value, which can be
retrieved from the VmHWM field in /proc/pid/status, per benchmark
iteration or test scenario.
[akpm@linux-foundation.org: clarify behaviour in documentation]
Signed-off-by: Petr Cermak <petrcermak@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Primiano Tucci <primiano@chromium.org>
Cc: Petr Cermak <petrcermak@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | Documentation/filesystems/proc.txt | 4 | ||||
| -rw-r--r-- | fs/proc/task_mmu.c | 14 | ||||
| -rw-r--r-- | include/linux/mm.h | 5 |
3 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index cf8fc2f0b34b..0b3448dba9ec 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -489,6 +489,10 @@ To clear the bits for the file mapped pages associated with the process To clear the soft-dirty bit > echo 4 > /proc/PID/clear_refs +To reset the peak resident set size ("high water mark") to the process's +current value: + > echo 5 > /proc/PID/clear_refs + Any other value written to /proc/PID/clear_refs will have no effect. The /proc/pid/pagemap gives the PFN, which can be used to find the pageflags diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0e36c1e49fe3..1359a911d194 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -732,6 +732,7 @@ enum clear_refs_types { CLEAR_REFS_ANON, CLEAR_REFS_MAPPED, CLEAR_REFS_SOFT_DIRTY, + CLEAR_REFS_MM_HIWATER_RSS, CLEAR_REFS_LAST, }; @@ -907,6 +908,18 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, .mm = mm, .private = &cp, }; + + if (type == CLEAR_REFS_MM_HIWATER_RSS) { + /* + * Writing 5 to /proc/pid/clear_refs resets the peak + * resident set size to this mm's current rss value. + */ + down_write(&mm->mmap_sem); + reset_mm_hiwater_rss(mm); + up_write(&mm->mmap_sem); + goto out_mm; + } + down_read(&mm->mmap_sem); if (type == CLEAR_REFS_SOFT_DIRTY) { for (vma = mm->mmap; vma; vma = vma->vm_next) { @@ -928,6 +941,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, mmu_notifier_invalidate_range_end(mm, 0, -1); flush_tlb_mm(mm); up_read(&mm->mmap_sem); +out_mm: mmput(mm); } put_task_struct(task); diff --git a/include/linux/mm.h b/include/linux/mm.h index bd52e2f14027..9bee7ec0c31f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1408,6 +1408,11 @@ static inline void update_hiwater_vm(struct mm_struct *mm) mm->hiwater_vm = mm->total_vm; } +static inline void reset_mm_hiwater_rss(struct mm_struct *mm) +{ + mm->hiwater_rss = get_mm_rss(mm); +} + static inline void setmax_mm_hiwater_rss(unsigned long *maxrss, struct mm_struct *mm) { |