From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A670EE94130 for ; Fri, 6 Oct 2023 21:49:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233772AbjJFVtR (ORCPT ); Fri, 6 Oct 2023 17:49:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233810AbjJFVtQ (ORCPT ); Fri, 6 Oct 2023 17:49:16 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABF9BCF for ; Fri, 6 Oct 2023 14:49:06 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02528C433C8; Fri, 6 Oct 2023 21:49:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1696628946; bh=R1C8FeWOsKmkMvHMgOVSdrWK9o+3lR23rmv8tIzed2k=; h=Date:To:From:Subject:From; b=J2IQL1/n+xu8nJyQvtYCG2RszGMBWHsY78I4F1WK86GFHJ/nYraf5K/G1YjATw6I1 +8gkIKKVAyJNKtWslxzxtFVfTo3y8YhAOoQdN0pofZlfgPtg5+h0we/HfYHYxbl93e OeQLZ7XVI17GsAWs4ZUOaNTw/w6FkZjgv7W0LtuE= Date: Fri, 06 Oct 2023 14:49:03 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, vbabka@suse.cz, sudeep.holla@arm.com, pasha.tatashin@soleen.com, mhocko@suse.com, mgorman@techsingularity.net, jweiner@redhat.com, david@redhat.com, dave.hansen@linux.intel.com, cl@linux.com, arjan@linux.intel.com, ying.huang@intel.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-pcp-decrease-pcp-high-if-free-pages-high-watermark.patch removed from -mm tree Message-Id: <20231006214906.02528C433C8@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm, pcp: decrease PCP high if free pages < high watermark has been removed from the -mm tree. Its filename was mm-pcp-decrease-pcp-high-if-free-pages-high-watermark.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Huang Ying Subject: mm, pcp: decrease PCP high if free pages < high watermark Date: Tue, 26 Sep 2023 14:09:09 +0800 One target of PCP is to minimize pages in PCP if the system free pages is too few. To reach that target, when page reclaiming is active for the zone (ZONE_RECLAIM_ACTIVE), we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. But this may be too late because the background page reclaiming may introduce latency for some workloads. So, in this patch, during page allocation we will detect whether the number of free pages of the zone is below high watermark. If so, we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. With this, we can reduce the possibility of the premature background page reclaiming caused by too large PCP. The high watermark checking is done in allocating path to reduce the overhead in hotter freeing path. Link: https://lkml.kernel.org/r/20230926060911.266511-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 1 + mm/page_alloc.c | 22 ++++++++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-) --- a/include/linux/mmzone.h~mm-pcp-decrease-pcp-high-if-free-pages-high-watermark +++ a/include/linux/mmzone.h @@ -1004,6 +1004,7 @@ enum zone_flags { * Cleared when kswapd is woken. */ ZONE_RECLAIM_ACTIVE, /* kswapd may be scanning the zone. */ + ZONE_BELOW_HIGH, /* zone is below high watermark. */ }; static inline unsigned long zone_managed_pages(struct zone *zone) --- a/mm/page_alloc.c~mm-pcp-decrease-pcp-high-if-free-pages-high-watermark +++ a/mm/page_alloc.c @@ -2409,7 +2409,13 @@ static int nr_pcp_high(struct per_cpu_pa return min(batch << 2, pcp->high); } - if (pcp->count >= high && high_min != high_max) { + if (high_min == high_max) + return high; + + if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) { + pcp->high = max(high - (batch << pcp->free_factor), high_min); + high = max(pcp->count, high_min); + } else if (pcp->count >= high) { int need_high = (batch << pcp->free_factor) + batch; /* pcp->high should be large enough to hold batch freed pages */ @@ -2459,6 +2465,10 @@ static void free_unref_page_commit(struc if (pcp->count >= high) { free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high), pcp, pindex); + if (test_bit(ZONE_BELOW_HIGH, &zone->flags) && + zone_watermark_ok(zone, 0, high_wmark_pages(zone), + ZONE_MOVABLE, 0)) + clear_bit(ZONE_BELOW_HIGH, &zone->flags); } } @@ -2765,7 +2775,7 @@ static int nr_pcp_alloc(struct per_cpu_p * If we had larger pcp->high, we could avoid to allocate from * zone. */ - if (high_min != high_max && !test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) + if (high_min != high_max && !test_bit(ZONE_BELOW_HIGH, &zone->flags)) high = pcp->high = min(high + batch, high_max); if (!order) { @@ -3226,6 +3236,14 @@ retry: } } + mark = high_wmark_pages(zone); + if (zone_watermark_fast(zone, order, mark, + ac->highest_zoneidx, alloc_flags, + gfp_mask)) + goto try_this_zone; + else if (!test_bit(ZONE_BELOW_HIGH, &zone->flags)) + set_bit(ZONE_BELOW_HIGH, &zone->flags); + mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); if (!zone_watermark_fast(zone, order, mark, ac->highest_zoneidx, alloc_flags, _ Patches currently in -mm which might be from ying.huang@intel.com are mm-fix-draining-remote-pageset.patch