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authorxu xin <xu.xin16@zte.com.cn>2022-04-28 23:16:16 -0700
committerakpm <akpm@linux-foundation.org>2022-04-28 23:16:16 -0700
commit7609385337a4feb6236e42dcd0df2185683ce839 (patch)
tree2ec02ae22d747eb005c0545d294ba3dac72c8750 /mm/ksm.c
parentba91fb7dd03c4f463453f28af24851097a6547fb (diff)
ksm: count ksm merging pages for each process
Some applications or containers want to use KSM by calling madvise() to advise areas of address space to be MERGEABLE. But they may not know which applications are more likely to cause real merges in the deployment. If this patch is applied, it helps them know their corresponding number of merged pages, and then optimize their app code. As current KSM only counts the number of KSM merging pages(e.g. ksm_pages_sharing and ksm_pages_shared) of the whole system, we cannot see the more fine-grained KSM merging, for the upper application optimization, the merging area cannot be set easily according to the KSM page merging probability of each process. Therefore, it is necessary to add extra statistical means so that the upper level users can know the detailed KSM merging information of each process. We add a new proc file named as ksm_merging_pages under /proc/<pid>/ to indicate the involved ksm merging pages of this process. [akpm@linux-foundation.org: fix comment typo, remove BUG_ON()s] Link: https://lkml.kernel.org/r/20220325082318.2352853-1-xu.xin16@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Reported-by: Zeal Robot <zealci@zte.com.cn> Cc: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Ohhoon Kwon <ohoono.kwon@samsung.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Feng Tang <feng.tang@intel.com> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/ksm.c')
-rw-r--r--mm/ksm.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 063a48eeb5ee..94bb0f049806 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -638,6 +638,9 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node)
ksm_pages_sharing--;
else
ksm_pages_shared--;
+
+ rmap_item->mm->ksm_merging_pages--;
+
VM_BUG_ON(stable_node->rmap_hlist_len <= 0);
stable_node->rmap_hlist_len--;
put_anon_vma(rmap_item->anon_vma);
@@ -785,6 +788,9 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
ksm_pages_sharing--;
else
ksm_pages_shared--;
+
+ rmap_item->mm->ksm_merging_pages--;
+
VM_BUG_ON(stable_node->rmap_hlist_len <= 0);
stable_node->rmap_hlist_len--;
@@ -2007,6 +2013,8 @@ static void stable_tree_append(struct rmap_item *rmap_item,
ksm_pages_sharing++;
else
ksm_pages_shared++;
+
+ rmap_item->mm->ksm_merging_pages++;
}
/*