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 8DFD9C433F5 for ; Fri, 22 Oct 2021 19:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76C33610EA for ; Fri, 22 Oct 2021 19:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234088AbhJVT2E (ORCPT ); Fri, 22 Oct 2021 15:28:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:44132 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233564AbhJVT2E (ORCPT ); Fri, 22 Oct 2021 15:28:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C2B8C6109D; Fri, 22 Oct 2021 19:25:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1634930746; bh=4K5LRyfK71eLxh+5zn239Uqi5tBVMSgTeVUO2U0yDA0=; h=Date:From:To:Subject:From; b=n4aO4nlowXBCtPm3Sev+/hAOW/+vw3PomEv5ESlqaN13yZwYGHulykZpFL/RQVT/y IR61e4USGmg6ZwgkSRS0UjA3HC87pRgLNOGpNZcaiFR4+JqzDM2hUJBJ7ViavrwthD z1Yy9RFLu19lgrq3q18tAYGYKQmzPGwu8QKUw6gw= Date: Fri, 22 Oct 2021 12:25:45 -0700 From: akpm@linux-foundation.org To: adilger.kernel@dilger.ca, corbet@lwn.net, david@fromorbit.com, djwong@kernel.org, hannes@cmpxchg.org, mgorman@techsingularity.net, mhocko@suse.com, mm-commits@vger.kernel.org, neilb@suse.de, riel@surriel.com, tytso@mit.edu, vbabka@suse.cz, willy@infradead.org Subject: + mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch added to -mm tree Message-ID: <20211022192545.q2WSvFx2D%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/vmscan: throttle reclaim when no progress is being made has been added to the -mm tree. Its filename is mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mel Gorman Subject: mm/vmscan: throttle reclaim when no progress is being made 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. [vbabka@suse.cz: Remove redundant code] Link: https://lkml.kernel.org/r/20211022144651.19914-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Andreas Dilger Cc: "Darrick J . Wong" Cc: Dave Chinner Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Matthew Wilcox Cc: Michal Hocko Cc: NeilBrown Cc: Rik van Riel Cc: "Theodore Ts'o" Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 1 + include/trace/events/vmscan.h | 4 +++- mm/memcontrol.c | 10 +--------- mm/vmscan.c | 28 ++++++++++++++++++++++++++++ 4 files changed, 33 insertions(+), 10 deletions(-) --- a/include/linux/mmzone.h~mm-vmscan-throttle-reclaim-when-no-progress-is-being-made +++ a/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, }; --- a/include/trace/events/vmscan.h~mm-vmscan-throttle-reclaim-when-no-progress-is-being-made +++ a/include/trace/events/vmscan.h @@ -29,11 +29,13 @@ #define _VMSCAN_THROTTLE_WRITEBACK (1 << VMSCAN_THROTTLE_WRITEBACK) #define _VMSCAN_THROTTLE_ISOLATED (1 << VMSCAN_THROTTLE_ISOLATED) +#define _VMSCAN_THROTTLE_NOPROGRESS (1 << VMSCAN_THROTTLE_NOPROGRESS) #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" --- a/mm/memcontrol.c~mm-vmscan-throttle-reclaim-when-no-progress-is-being-made +++ a/mm/memcontrol.c @@ -3489,19 +3489,11 @@ static int mem_cgroup_force_empty(struct /* try to free all pages in this cgroup */ while (nr_retries && page_counter_read(&memcg->memory)) { - int progress; - if (signal_pending(current)) return -EINTR; - progress = 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); - } - } return 0; --- a/mm/vmscan.c~mm-vmscan-throttle-reclaim-when-no-progress-is-being-made +++ a/mm/vmscan.c @@ -3329,6 +3329,33 @@ static inline bool compaction_ready(stru return zone_watermark_ok_safe(zone, 0, watermark, sc->reclaim_idx); } +static void consider_reclaim_throttle(pg_data_t *pgdat, struct scan_control *sc) +{ + /* If reclaim is making progress, wake any throttled tasks. */ + if (sc->nr_reclaimed) { + wait_queue_head_t *wqh; + + wqh = &pgdat->reclaim_wait[VMSCAN_THROTTLE_NOPROGRESS]; + if (waitqueue_active(wqh)) + wake_up(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 only * try to reclaim pages from zones which will satisfy the caller's allocation @@ -3413,6 +3440,7 @@ static void shrink_zones(struct zonelist continue; last_pgdat = zone->zone_pgdat; shrink_node(zone->zone_pgdat, sc); + consider_reclaim_throttle(zone->zone_pgdat, sc); } /* _ Patches currently in -mm which might be from mgorman@techsingularity.net are mm-vmscan-throttle-reclaim-until-some-writeback-completes-if-congested.patch mm-vmscan-throttle-reclaim-and-compaction-when-too-may-pages-are-isolated.patch mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch mm-page_alloc-remove-the-throttling-logic-from-the-page-allocator.patch mm-vmscan-centralise-timeout-values-for-reclaim_throttle.patch mm-vmscan-increase-the-timeout-if-page-reclaim-is-not-making-progress.patch mm-vmscan-delay-waking-of-tasks-throttled-on-noprogress.patch