Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754302AbcC1F3F (ORCPT ); Mon, 28 Mar 2016 01:29:05 -0400 Received: from mail-pf0-f179.google.com ([209.85.192.179]:35352 "EHLO mail-pf0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754139AbcC1F1b (ORCPT ); Mon, 28 Mar 2016 01:27:31 -0400 From: js1304@gmail.com X-Google-Original-From: iamjoonsoo.kim@lge.com To: Andrew Morton Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Jesper Dangaard Brouer , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH 06/11] mm/slab: don't keep free slabs if free_objects exceeds free_limit Date: Mon, 28 Mar 2016 14:26:56 +0900 Message-Id: <1459142821-20303-7-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1459142821-20303-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1459142821-20303-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2218 Lines: 68 From: Joonsoo Kim Currently, determination to free a slab is done whenever free object is put into the slab. This has a problem that free slabs are not freed even if we have free slabs and have more free_objects than free_limit when processed slab isn't a free slab. This would cause to keep too much memory in the slab subsystem. This patch try to fix it by checking number of free object after all free work is done. If there is free slab at that time, we can free it so we keep free slab as minimal as possible. Signed-off-by: Joonsoo Kim --- mm/slab.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index b96f381..df11757 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3258,6 +3258,9 @@ static void free_block(struct kmem_cache *cachep, void **objpp, { int i; struct kmem_cache_node *n = get_node(cachep, node); + struct page *page; + + n->free_objects += nr_objects; for (i = 0; i < nr_objects; i++) { void *objp; @@ -3270,17 +3273,11 @@ static void free_block(struct kmem_cache *cachep, void **objpp, check_spinlock_acquired_node(cachep, node); slab_put_obj(cachep, page, objp); STATS_DEC_ACTIVE(cachep); - n->free_objects++; /* fixup slab chains */ - if (page->active == 0) { - if (n->free_objects > n->free_limit) { - n->free_objects -= cachep->num; - list_add_tail(&page->lru, list); - } else { - list_add(&page->lru, &n->slabs_free); - } - } else { + if (page->active == 0) + list_add(&page->lru, &n->slabs_free); + else { /* Unconditionally move a slab to the end of the * partial list on free - maximum time for the * other objects to be freed, too. @@ -3288,6 +3285,14 @@ static void free_block(struct kmem_cache *cachep, void **objpp, list_add_tail(&page->lru, &n->slabs_partial); } } + + while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) { + n->free_objects -= cachep->num; + + page = list_last_entry(&n->slabs_free, struct page, lru); + list_del(&page->lru); + list_add(&page->lru, list); + } } static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) -- 1.9.1