From 7f60c214fd3a360461f3286c6908084f7f8b1950 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Mon, 24 May 2010 14:32:18 -0700 Subject: mm: migration: share the anon_vma ref counts between KSM and page migration For clarity of review, KSM and page migration have separate refcounts on the anon_vma. While clear, this is a waste of memory. This patch gets KSM and page migration to share their toys in a spirit of harmony. Signed-off-by: Mel Gorman Reviewed-by: Minchan Kim Reviewed-by: KOSAKI Motohiro Reviewed-by: Christoph Lameter Reviewed-by: KAMEZAWA Hiroyuki Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/ksm.c | 4 ++-- mm/migrate.c | 4 ++-- mm/rmap.c | 6 ++---- 3 files changed, 6 insertions(+), 8 deletions(-) (limited to 'mm') diff --git a/mm/ksm.c b/mm/ksm.c index 956880f2ff4..6c3e99b4ae7 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -318,14 +318,14 @@ static void hold_anon_vma(struct rmap_item *rmap_item, struct anon_vma *anon_vma) { rmap_item->anon_vma = anon_vma; - atomic_inc(&anon_vma->ksm_refcount); + atomic_inc(&anon_vma->external_refcount); } static void drop_anon_vma(struct rmap_item *rmap_item) { struct anon_vma *anon_vma = rmap_item->anon_vma; - if (atomic_dec_and_lock(&anon_vma->ksm_refcount, &anon_vma->lock)) { + if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) { int empty = list_empty(&anon_vma->head); spin_unlock(&anon_vma->lock); if (empty) diff --git a/mm/migrate.c b/mm/migrate.c index b768a1d4fa4..42a3d24d110 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -601,7 +601,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, rcu_read_lock(); rcu_locked = 1; anon_vma = page_anon_vma(page); - atomic_inc(&anon_vma->migrate_refcount); + atomic_inc(&anon_vma->external_refcount); } /* @@ -643,7 +643,7 @@ skip_unmap: rcu_unlock: /* Drop an anon_vma reference if we took one */ - if (anon_vma && atomic_dec_and_lock(&anon_vma->migrate_refcount, &anon_vma->lock)) { + if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) { int empty = list_empty(&anon_vma->head); spin_unlock(&anon_vma->lock); if (empty) diff --git a/mm/rmap.c b/mm/rmap.c index f522cb00864..b5c320f7d0a 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -250,8 +250,7 @@ static void anon_vma_unlink(struct anon_vma_chain *anon_vma_chain) list_del(&anon_vma_chain->same_anon_vma); /* We must garbage collect the anon_vma if it's empty */ - empty = list_empty(&anon_vma->head) && !ksm_refcount(anon_vma) && - !migrate_refcount(anon_vma); + empty = list_empty(&anon_vma->head) && !anonvma_external_refcount(anon_vma); spin_unlock(&anon_vma->lock); if (empty) @@ -275,8 +274,7 @@ static void anon_vma_ctor(void *data) struct anon_vma *anon_vma = data; spin_lock_init(&anon_vma->lock); - ksm_refcount_init(anon_vma); - migrate_refcount_init(anon_vma); + anonvma_external_refcount_init(anon_vma); INIT_LIST_HEAD(&anon_vma->head); } -- cgit v1.2.3-70-g09d2