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-rw-r--r--Documentation/filesystems/proc.txt4
-rw-r--r--fs/proc/task_mmu.c14
-rw-r--r--include/linux/mm.h5
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)
{