On Wed, 7 Jan 2015 03:30:42 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > tree: git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-writeback-20150106 > head: 393b71c00e25227a020f9dbf8ffdddebac4fdf1e > commit: d3ef989a8ce459778acbb511fc03d0d85f11d4cc [86/265] fs/proc/task_mmu.c: reduce excessive indentation in clear_refs_write > config: parisc-c3000_defconfig (attached as .config) > reproduce: > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout d3ef989a8ce459778acbb511fc03d0d85f11d4cc > # save the attached .config to linux build tree > make.cross ARCH=parisc > > All warnings: > > fs/proc/task_mmu.c: In function 'clear_refs_write': > >> fs/proc/task_mmu.c:858:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] > struct clear_refs_private cp = { > ^ I wasn't able to find a way of fixing this which I liked, so I dropped it. task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss.patch needed rework. Peter, please check carefully: From: Petr Cermak <petrcermak@xxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx: clarify behaviour in documentation] Signed-off-by: Petr Cermak <petrcermak@xxxxxxxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Primiano Tucci <primiano@xxxxxxxxxxxx> Cc: Petr Cermak <petrcermak@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/filesystems/proc.txt | 4 ++++ fs/proc/task_mmu.c | 14 ++++++++++++++ include/linux/mm.h | 5 +++++ 3 files changed, 23 insertions(+) diff -puN Documentation/filesystems/proc.txt~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss Documentation/filesystems/proc.txt --- a/Documentation/filesystems/proc.txt~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss +++ a/Documentation/filesystems/proc.txt @@ -488,6 +488,10 @@ To clear the bits for the file mapped pa 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 -puN fs/proc/task_mmu.c~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss +++ a/fs/proc/task_mmu.c @@ -747,6 +747,7 @@ enum clear_refs_types { CLEAR_REFS_ANON, CLEAR_REFS_MAPPED, CLEAR_REFS_SOFT_DIRTY, + CLEAR_REFS_MM_HIWATER_RSS, CLEAR_REFS_LAST, }; @@ -861,6 +862,18 @@ static ssize_t clear_refs_write(struct f .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) { @@ -903,6 +916,7 @@ static ssize_t clear_refs_write(struct f 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 -puN include/linux/mm.h~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss include/linux/mm.h --- a/include/linux/mm.h~task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss +++ a/include/linux/mm.h @@ -1366,6 +1366,11 @@ static inline void update_hiwater_vm(str 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) { _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>