]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
mm/ksm.c is doing an unneeded _notify in write_protect_page.
authorRobin Holt <holt@sgi.com>
Tue, 23 Mar 2010 20:35:26 +0000 (13:35 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 24 Mar 2010 23:31:20 +0000 (16:31 -0700)
commitcb53237513bd1e090cce120efe12ede72c932b5f
tree43d0665b57b654cf10ea12233e8234367e1634e0
parent20072205fcdf7d85cd3101f1f11dfab333c5fd0c
mm/ksm.c is doing an unneeded _notify in write_protect_page.

ksm.c's write_protect_page implements a lockless means of verifying a page
does not have any users of the page which are not accounted for via other
kernel tracking means.  It does this by removing the writable pte with TLB
flushes, checking the page_count against the total known users, and then
using set_pte_at_notify to make it a read-only entry.

An unneeded mmu_notifier callout is made in the case where the known users
does not match the page_count.  In that event, we are inserting the
identical pte and there is no need for the set_pte_at_notify, but rather
the simpler set_pte_at suffices.

Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Izik Eidus <ieidus@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Chris Wright <chrisw@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/ksm.c