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authorDavid Hildenbrand <david@redhat.com>2023-04-22 22:54:18 +0200
committerAndrew Morton <akpm@linux-foundation.org>2023-05-02 17:21:49 -0700
commit24139c07f413ef4b555482c758343d71392a19bc (patch)
tree59c520ceba8cfb5493d2154df6661f12a12459da /kernel
parent70307b0e297a6634be855c49525ccbea50922a90 (diff)
mm/ksm: unmerge and clear VM_MERGEABLE when setting PR_SET_MEMORY_MERGE=0
Patch series "mm/ksm: improve PR_SET_MEMORY_MERGE=0 handling and cleanup disabling KSM", v2. (1) Make PR_SET_MEMORY_MERGE=0 unmerge pages like setting MADV_UNMERGEABLE does, (2) add a selftest for it and (3) factor out disabling of KSM from s390/gmap code. This patch (of 3): Let's unmerge any KSM pages when setting PR_SET_MEMORY_MERGE=0, and clear the VM_MERGEABLE flag from all VMAs -- just like KSM would. Of course, only do that if we previously set PR_SET_MEMORY_MERGE=1. Link: https://lkml.kernel.org/r/20230422205420.30372-1-david@redhat.com Link: https://lkml.kernel.org/r/20230422205420.30372-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Stefan Roesch <shr@devkernel.io> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sys.c12
1 files changed, 3 insertions, 9 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 72cdb16e2636..339fee3eff6a 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2695,16 +2695,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
if (mmap_write_lock_killable(me->mm))
return -EINTR;
- if (arg2) {
+ if (arg2)
error = ksm_enable_merge_any(me->mm);
- } else {
- /*
- * TODO: we might want disable KSM on all VMAs and
- * trigger unsharing to completely disable KSM.
- */
- clear_bit(MMF_VM_MERGE_ANY, &me->mm->flags);
- error = 0;
- }
+ else
+ error = ksm_disable_merge_any(me->mm);
mmap_write_unlock(me->mm);
break;
case PR_GET_MEMORY_MERGE: