linux-kernel - [RFC V2 10/12] mm: Ignore madvise(MADV_MERGEABLE) request for VM

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Date:   Mon, 30 Jan 2017 09:05:51 +0530
From:   Anshuman Khandual <khandual@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     mhocko@...e.com, vbabka@...e.cz, mgorman@...e.de,
        minchan@...nel.org, aneesh.kumar@...ux.vnet.ibm.com,
        bsingharora@...il.com, srikar@...ux.vnet.ibm.com,
        haren@...ux.vnet.ibm.com, jglisse@...hat.com,
        dave.hansen@...el.com, dan.j.williams@...el.com
Subject: [RFC V2 10/12] mm: Ignore madvise(MADV_MERGEABLE) request for VM_CDM marked VMAs

VMA containing CDM memory should be excluded from KSM merging. This change
makes madvise(MADV_MERGEABLE) request on target VMA to be ignored.

Signed-off-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com>
---
 mm/ksm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/ksm.c b/mm/ksm.c
index 9ae6011..2fb8939 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -37,6 +37,7 @@
 #include <linux/freezer.h>
 #include <linux/oom.h>
 #include <linux/numa.h>
+#include <linux/mempolicy.h>
 
 #include <asm/tlbflush.h>
 #include "internal.h"
@@ -1751,6 +1752,9 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
 				 VM_HUGETLB | VM_MIXEDMAP))
 			return 0;		/* just ignore the advice */
 
+		if (is_cdm_vma(vma))
+			return 0;
+
 #ifdef VM_SAO
 		if (*vm_flags & VM_SAO)
 			return 0;
-- 
2.9.3