From 695f055936938c674473ea071ca7359a863551e7 Mon Sep 17 00:00:00 2001 From: Petr Cermak Date: Thu, 12 Feb 2015 15:01:00 -0800 Subject: 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 Cc: Bjorn Helgaas Cc: Primiano Tucci Cc: Petr Cermak Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'fs') diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0e36c1e..1359a91 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); -- cgit v1.1