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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 002CDC433F5 for ; Fri, 8 Oct 2021 13:54:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A751560FD8 for ; Fri, 8 Oct 2021 13:54:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A751560FD8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 4AA1B6B0074; Fri, 8 Oct 2021 09:54:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 45AEF6B0075; Fri, 8 Oct 2021 09:54:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3229E900002; Fri, 8 Oct 2021 09:54:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0187.hostedemail.com [216.40.44.187]) by kanga.kvack.org (Postfix) with ESMTP id 234CB6B0074 for ; Fri, 8 Oct 2021 09:54:16 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BD12B18012CE4 for ; Fri, 8 Oct 2021 13:54:15 +0000 (UTC) X-FDA: 78673414470.29.9FDEAAF Received: from outbound-smtp55.blacknight.com (outbound-smtp55.blacknight.com [46.22.136.239]) by imf28.hostedemail.com (Postfix) with ESMTP id 207D49002F16 for ; Fri, 8 Oct 2021 13:54:15 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail06.blacknight.ie [81.17.255.152]) by outbound-smtp55.blacknight.com (Postfix) with ESMTPS id C55C9FAB69 for ; Fri, 8 Oct 2021 14:54:13 +0100 (IST) Received: (qmail 6295 invoked from network); 8 Oct 2021 13:54:13 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.17.29]) by 81.17.254.9 with ESMTPA; 8 Oct 2021 13:54:13 -0000 From: Mel Gorman To: Linux-MM Cc: NeilBrown , Theodore Ts'o , Andreas Dilger , "Darrick J . Wong" , Matthew Wilcox , Michal Hocko , Dave Chinner , Rik van Riel , Vlastimil Babka , Johannes Weiner , Jonathan Corbet , Linux-fsdevel , LKML , Mel Gorman Subject: [PATCH 3/8] mm/vmscan: Throttle reclaim when no progress is being made Date: Fri, 8 Oct 2021 14:53:27 +0100 Message-Id: <20211008135332.19567-4-mgorman@techsingularity.net> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211008135332.19567-1-mgorman@techsingularity.net> References: <20211008135332.19567-1-mgorman@techsingularity.net> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 207D49002F16 X-Stat-Signature: qua9mkiccyroctt6zyrrpq1c4zahjes1 Authentication-Results: imf28.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf28.hostedemail.com: domain of mgorman@techsingularity.net designates 46.22.136.239 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net X-HE-Tag: 1633701255-209627 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Memcg reclaim throttles on congestion if no reclaim progress is made. This makes little sense, it might be due to writeback or a host of other factors. For !memcg reclaim, it's messy. Direct reclaim primarily is throttled in the page allocator if it is failing to make progress. Kswapd throttles if too many pages are under writeback and marked for immediate reclaim. This patch explicitly throttles if reclaim is failing to make progress. Signed-off-by: Mel Gorman --- include/linux/mmzone.h | 1 + include/trace/events/vmscan.h | 4 +++- mm/memcontrol.c | 10 +-------- mm/vmscan.c | 38 +++++++++++++++++++++++++++++++++++ 4 files changed, 43 insertions(+), 10 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ca65d6a64bdd..7c08cc91d526 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -276,6 +276,7 @@ enum lru_list { enum vmscan_throttle_state { VMSCAN_THROTTLE_WRITEBACK, VMSCAN_THROTTLE_ISOLATED, + VMSCAN_THROTTLE_NOPROGRESS, NR_VMSCAN_THROTTLE, }; =20 diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.= h index d4905bd9e9c4..f25a6149d3ba 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -29,11 +29,13 @@ =20 #define _VMSCAN_THROTTLE_WRITEBACK (1 << VMSCAN_THROTTLE_WRITEBACK) #define _VMSCAN_THROTTLE_ISOLATED (1 << VMSCAN_THROTTLE_ISOLATED) +#define _VMSCAN_THROTTLE_NOPROGRESS (1 << VMSCAN_THROTTLE_NOPROGRESS) =20 #define show_throttle_flags(flags) \ (flags) ? __print_flags(flags, "|", \ {_VMSCAN_THROTTLE_WRITEBACK, "VMSCAN_THROTTLE_WRITEBACK"}, \ - {_VMSCAN_THROTTLE_ISOLATED, "VMSCAN_THROTTLE_ISOLATED"} \ + {_VMSCAN_THROTTLE_ISOLATED, "VMSCAN_THROTTLE_ISOLATED"}, \ + {_VMSCAN_THROTTLE_NOPROGRESS, "VMSCAN_THROTTLE_NOPROGRESS"} \ ) : "VMSCAN_THROTTLE_NONE" =20 =20 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6da5020a8656..8b33152c9b85 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3465,19 +3465,11 @@ static int mem_cgroup_force_empty(struct mem_cgro= up *memcg) =20 /* try to free all pages in this cgroup */ while (nr_retries && page_counter_read(&memcg->memory)) { - int progress; - if (signal_pending(current)) return -EINTR; =20 - progress =3D try_to_free_mem_cgroup_pages(memcg, 1, - GFP_KERNEL, true); - if (!progress) { + if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true)) nr_retries--; - /* maybe some writeback is necessary */ - congestion_wait(BLK_RW_ASYNC, HZ/10); - } - } =20 return 0; diff --git a/mm/vmscan.c b/mm/vmscan.c index 9ce4195d4123..cdebfc618179 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3311,6 +3311,33 @@ static inline bool compaction_ready(struct zone *z= one, struct scan_control *sc) return zone_watermark_ok_safe(zone, 0, watermark, sc->reclaim_idx); } =20 +static void consider_reclaim_throttle(pg_data_t *pgdat, struct scan_cont= rol *sc) +{ + /* If reclaim is making progress, wake any throttled tasks. */ + if (sc->nr_reclaimed) { + wait_queue_head_t *wqh; + + wqh =3D &pgdat->reclaim_wait[VMSCAN_THROTTLE_NOPROGRESS]; + if (waitqueue_active(wqh)) + wake_up_all(wqh); + + return; + } + + /* + * Do not throttle kswapd on NOPROGRESS as it will throttle on + * VMSCAN_THROTTLE_WRITEBACK if there are too many pages under + * writeback and marked for immediate reclaim at the tail of + * the LRU. + */ + if (current_is_kswapd()) + return; + + /* Throttle if making no progress at high prioities. */ + if (sc->priority < DEF_PRIORITY - 2) + reclaim_throttle(pgdat, VMSCAN_THROTTLE_NOPROGRESS, HZ/10); +} + /* * This is the direct reclaim path, for page-allocating processes. We o= nly * try to reclaim pages from zones which will satisfy the caller's alloc= ation @@ -3395,6 +3422,7 @@ static void shrink_zones(struct zonelist *zonelist,= struct scan_control *sc) continue; last_pgdat =3D zone->zone_pgdat; shrink_node(zone->zone_pgdat, sc); + consider_reclaim_throttle(zone->zone_pgdat, sc); } =20 /* @@ -3769,6 +3797,16 @@ unsigned long try_to_free_mem_cgroup_pages(struct = mem_cgroup *memcg, trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed); set_task_reclaim_state(current, NULL); =20 + if (!nr_reclaimed) { + struct zoneref *z; + pg_data_t *pgdat; + + z =3D first_zones_zonelist(zonelist, sc.reclaim_idx, sc.nodemask); + pgdat =3D zonelist_zone(z)->zone_pgdat; + + reclaim_throttle(pgdat, VMSCAN_THROTTLE_NOPROGRESS, HZ/10); + } + return nr_reclaimed; } #endif --=20 2.31.1