From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756349AbcIFNxz (ORCPT ); Tue, 6 Sep 2016 09:53:55 -0400 Received: from mx2.suse.de ([195.135.220.15]:49628 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755747AbcIFNxT (ORCPT ); Tue, 6 Sep 2016 09:53:19 -0400 From: Vlastimil Babka To: Michal Hocko , Andrew Morton , Arkadiusz Miskiewicz , Ralf-Peter Rohbeck , Olaf Hering Cc: linux-kernel@vger.kernel.org, Linus Torvalds , linux-mm@kvack.org, Vlastimil Babka , Mel Gorman , Joonsoo Kim , David Rientjes , Rik van Riel , Michal Hocko Subject: [PATCH 3/4] mm, compaction: restrict full priority to non-costly orders Date: Tue, 6 Sep 2016 15:52:57 +0200 Message-Id: <20160906135258.18335-4-vbabka@suse.cz> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160906135258.18335-1-vbabka@suse.cz> References: <20160906135258.18335-1-vbabka@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The new ultimate compaction priority disables some heuristics, which may result in excessive cost. This is fine for non-costly orders where we want to try hard before resulting for OOM, but might be disruptive for costly orders which do not trigger OOM and should generally have some fallback. Thus, we disable the full priority for costly orders. Suggested-by: Michal Hocko Signed-off-by: Vlastimil Babka Cc: Michal Hocko Cc: Mel Gorman Cc: Joonsoo Kim Cc: David Rientjes Cc: Rik van Riel --- include/linux/compaction.h | 1 + mm/page_alloc.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 585d55cb0dc0..0d8415820fc3 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -9,6 +9,7 @@ enum compact_priority { COMPACT_PRIO_SYNC_FULL, MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL, COMPACT_PRIO_SYNC_LIGHT, + MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, COMPACT_PRIO_ASYNC, INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f8bed910e3cf..ff60a2837c58 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3165,6 +3165,7 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, int compaction_retries) { int max_retries = MAX_COMPACT_RETRIES; + int min_priority; if (!order) return false; @@ -3204,7 +3205,9 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, * if we exhausted all retries at the lower priorities */ check_priority: - if (*compact_priority > MIN_COMPACT_PRIORITY) { + min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? + MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; + if (*compact_priority > min_priority) { (*compact_priority)--; return true; } -- 2.9.3