The patch titled
Subject: ksm: count zero pages for each process
has been added to the -mm mm-unstable branch. Its filename is
ksm-count-zero-pages-for-each-process.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ksm-count-zero-pages-for-each-process.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: xu xin <xu.xin16@xxxxxxxxxx>
Subject: ksm: count zero pages for each process
Date: Fri, 30 Dec 2022 09:16:29 +0800 (CST)
As the number of ksm zero pages is not included in ksm_merging_pages per
process when enabling use_zero_pages, it's unclear of how many actual
pages are merged by KSM. To let users accurately estimate their memory
demands when unsharing KSM zero-pages, it's necessary to show KSM zero-
pages per process.
Since unsharing zero pages placed by KSM accurately is achieved, then
tracking empty pages merging and unmerging is not a difficult thing any
longer.
Since we already have /proc/<pid>/ksm_stat, just add the information of
zero_pages_sharing in it.
Link: https://lkml.kernel.org/r/202212300916292181912@xxxxxxxxxx
Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Xuexin Jiang <jiang.xuexin@xxxxxxxxxx>
Cc: Xiaokai Ran <ran.xiaokai@xxxxxxxxxx>
Cc: Yang Yang <yang.yang29@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/fs/proc/base.c~ksm-count-zero-pages-for-each-process
+++ a/fs/proc/base.c
@@ -3207,6 +3207,7 @@ static int proc_pid_ksm_stat(struct seq_
mm = get_task_mm(task);
if (mm) {
seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items);
+ seq_printf(m, "zero_pages_sharing %lu\n", mm->ksm_zero_pages_sharing);
mmput(mm);
}
--- a/include/linux/mm_types.h~ksm-count-zero-pages-for-each-process
+++ a/include/linux/mm_types.h
@@ -776,7 +776,7 @@ struct mm_struct {
#ifdef CONFIG_KSM
/*
* Represent how many pages of this process are involved in KSM
- * merging.
+ * merging (not including ksm_zero_pages_sharing).
*/
unsigned long ksm_merging_pages;
/*
@@ -784,6 +784,11 @@ struct mm_struct {
* including merged and not merged.
*/
unsigned long ksm_rmap_items;
+ /*
+ * Represent how many empty pages are merged with kernel zero
+ * pages when enabling KSM use_zero_pages.
+ */
+ unsigned long ksm_zero_pages_sharing;
#endif
#ifdef CONFIG_LRU_GEN
struct {
--- a/mm/ksm.c~ksm-count-zero-pages-for-each-process
+++ a/mm/ksm.c
@@ -794,6 +794,7 @@ static inline void clean_rmap_item_zero_
{
if (rmap_item->address & ZERO_PAGE_FLAG) {
ksm_zero_pages_sharing--;
+ rmap_item->mm->ksm_zero_pages_sharing--;
rmap_item->address &= PAGE_MASK;
}
}
@@ -2117,6 +2118,7 @@ static int try_to_merge_with_kernel_zero
if (!err) {
rmap_item->address |= ZERO_PAGE_FLAG;
ksm_zero_pages_sharing++;
+ rmap_item->mm->ksm_zero_pages_sharing++;
}
} else {
/* If the vma is out of date, we do not need to continue. */
_
Patches currently in -mm which might be from xu.xin16@xxxxxxxxxx are
ksm-abstract-the-function-try_to_get_old_rmap_item.patch
ksm-support-unsharing-zero-pages-placed-by-ksm.patch
ksm-count-all-zero-pages-placed-by-ksm.patch
ksm-count-zero-pages-for-each-process.patch
ksm-add-zero_pages_sharing-documentation.patch
selftest-add-testing-unsharing-and-counting-ksm-zero-page.patch
