+ ksm-add-ksm-zero-pages-for-each-process.patch added to mm-unstable branch

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled
     Subject: ksm: add ksm zero pages for each process
has been added to the -mm mm-unstable branch.  Its filename is
     ksm-add-ksm-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-add-ksm-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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: xu xin <xu.xin16@xxxxxxxxxx>
Subject: ksm: add ksm zero pages for each process
Date: Tue, 13 Jun 2023 11:09:38 +0800

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. In addition, it help users to know the actual KSM
profit because KSM-placed zero pages are also benefit from KSM.

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
'ksm_zero_pages' in it.

Link: https://lkml.kernel.org/r/20230613030938.185993-1-yang.yang29@xxxxxxxxxx
Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Xiaokai Ran <ran.xiaokai@xxxxxxxxxx>
Reviewed-by: Yang Yang <yang.yang29@xxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: Xuexin Jiang <jiang.xuexin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 fs/proc/base.c           |    1 +
 include/linux/ksm.h      |    8 +++++---
 include/linux/mm_types.h |    9 +++++++--
 mm/khugepaged.c          |    2 +-
 mm/ksm.c                 |    1 +
 mm/memory.c              |    4 ++--
 6 files changed, 17 insertions(+), 8 deletions(-)

--- a/fs/proc/base.c~ksm-add-ksm-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, "ksm_zero_pages %lu\n", mm->ksm_zero_pages);
 		seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages);
 		seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm));
 		mmput(mm);
--- a/include/linux/ksm.h~ksm-add-ksm-zero-pages-for-each-process
+++ a/include/linux/ksm.h
@@ -35,10 +35,12 @@ void __ksm_exit(struct mm_struct *mm);
 
 extern unsigned long ksm_zero_pages;
 
-static inline void ksm_might_unmap_zero_page(pte_t pte)
+static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte)
 {
-	if (is_ksm_zero_pte(pte))
+	if (is_ksm_zero_pte(pte)) {
 		ksm_zero_pages--;
+		mm->ksm_zero_pages--;
+	}
 }
 
 static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
@@ -109,7 +111,7 @@ static inline void ksm_exit(struct mm_st
 {
 }
 
-static inline void ksm_might_unmap_zero_page(pte_t pte)
+static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte)
 {
 }
 
--- a/include/linux/mm_types.h~ksm-add-ksm-zero-pages-for-each-process
+++ a/include/linux/mm_types.h
@@ -784,7 +784,7 @@ struct mm_struct {
 #ifdef CONFIG_KSM
 		/*
 		 * Represent how many pages of this process are involved in KSM
-		 * merging.
+		 * merging (not including ksm_zero_pages).
 		 */
 		unsigned long ksm_merging_pages;
 		/*
@@ -792,7 +792,12 @@ struct mm_struct {
 		 * including merged and not merged.
 		 */
 		unsigned long ksm_rmap_items;
-#endif
+		/*
+		 * Represent how many empty pages are merged with kernel zero
+		 * pages when enabling KSM use_zero_pages.
+		 */
+		unsigned long ksm_zero_pages;
+#endif /* CONFIG_KSM */
 #ifdef CONFIG_LRU_GEN
 		struct {
 			/* this mm_struct is on lru_gen_mm_list */
--- a/mm/khugepaged.c~ksm-add-ksm-zero-pages-for-each-process
+++ a/mm/khugepaged.c
@@ -710,7 +710,7 @@ static void __collapse_huge_page_copy_su
 				spin_lock(ptl);
 				ptep_clear(vma->vm_mm, address, _pte);
 				spin_unlock(ptl);
-				ksm_might_unmap_zero_page(pteval);
+				ksm_might_unmap_zero_page(vma->vm_mm, pteval);
 			}
 		} else {
 			src_page = pte_page(pteval);
--- a/mm/ksm.c~ksm-add-ksm-zero-pages-for-each-process
+++ a/mm/ksm.c
@@ -1233,6 +1233,7 @@ static int replace_page(struct vm_area_s
 		 */
 		newpte = pte_mkdirty(pte_mkspecial(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot)));
 		ksm_zero_pages++;
+		mm->ksm_zero_pages++;
 		/*
 		 * We're replacing an anonymous page with a zero page, which is
 		 * not anonymous. We need to do proper accounting otherwise we
--- a/mm/memory.c~ksm-add-ksm-zero-pages-for-each-process
+++ a/mm/memory.c
@@ -1434,7 +1434,7 @@ static unsigned long zap_pte_range(struc
 			zap_install_uffd_wp_if_needed(vma, addr, pte, details,
 						      ptent);
 			if (unlikely(!page)) {
-				ksm_might_unmap_zero_page(ptent);
+				ksm_might_unmap_zero_page(mm, ptent);
 				continue;
 			}
 
@@ -3133,7 +3133,7 @@ static vm_fault_t wp_page_copy(struct vm
 				inc_mm_counter(mm, MM_ANONPAGES);
 			}
 		} else {
-			ksm_might_unmap_zero_page(vmf->orig_pte);
+			ksm_might_unmap_zero_page(mm, vmf->orig_pte);
 			inc_mm_counter(mm, MM_ANONPAGES);
 		}
 		flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
_

Patches currently in -mm which might be from xu.xin16@xxxxxxxxxx are

ksm-support-unsharing-ksm-placed-zero-pages.patch
ksm-count-all-zero-pages-placed-by-ksm.patch
ksm-add-ksm-zero-pages-for-each-process.patch
ksm-consider-ksm-placed-zeropages-when-calculating-ksm-profit.patch
selftest-add-a-testcase-of-ksm-zero-pages.patch




[Index of Archives]     [Kernel Archive]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]

  Powered by Linux