From patchwork Wed May 12 09:54:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 436016 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42182C433ED for ; Wed, 12 May 2021 09:56:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C5BF613C4 for ; Wed, 12 May 2021 09:56:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230395AbhELJ5V (ORCPT ); Wed, 12 May 2021 05:57:21 -0400 Received: from outbound-smtp19.blacknight.com ([46.22.139.246]:56135 "EHLO outbound-smtp19.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230385AbhELJ5U (ORCPT ); Wed, 12 May 2021 05:57:20 -0400 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp19.blacknight.com (Postfix) with ESMTPS id AC6811C37E1 for ; Wed, 12 May 2021 10:56:11 +0100 (IST) Received: (qmail 29448 invoked from network); 12 May 2021 09:56:11 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.23.168]) by 81.17.254.9 with ESMTPA; 12 May 2021 09:56:11 -0000 From: Mel Gorman To: Andrew Morton Cc: Chuck Lever , Jesper Dangaard Brouer , Thomas Gleixner , Sebastian Andrzej Siewior , Peter Zijlstra , Ingo Molnar , Michal Hocko , Vlastimil Babka , Linux-MM , Linux-RT-Users , LKML , Mel Gorman Subject: [PATCH 6/9] mm/page_alloc: Reduce duration that IRQs are disabled for VM counters Date: Wed, 12 May 2021 10:54:55 +0100 Message-Id: <20210512095458.30632-7-mgorman@techsingularity.net> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210512095458.30632-1-mgorman@techsingularity.net> References: <20210512095458.30632-1-mgorman@techsingularity.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org IRQs are left disabled for the zone and node VM event counters. This is unnecessary as the affected counters are allowed to race for preemmption and IRQs. This patch reduces the scope of IRQs being disabled via local_[lock|unlock]_irq on !PREEMPT_RT kernels. One __mod_zone_freepage_state is still called with IRQs disabled. While this could be moved out, it's not free on all architectures as some require IRQs to be disabled for mod_zone_page_state on !PREEMPT_RT kernels. Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka --- mm/page_alloc.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7970efa142b0..5879b595b74b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3519,11 +3519,11 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, pcp = this_cpu_ptr(zone->per_cpu_pageset); list = &pcp->lists[migratetype]; page = __rmqueue_pcplist(zone, migratetype, alloc_flags, pcp, list); + local_unlock_irqrestore(&pagesets.lock, flags); if (page) { __count_zid_vm_events(PGALLOC, page_zonenum(page), 1); zone_statistics(preferred_zone, zone, 1); } - local_unlock_irqrestore(&pagesets.lock, flags); return page; } @@ -3575,15 +3575,15 @@ struct page *rmqueue(struct zone *preferred_zone, if (!page) page = __rmqueue(zone, order, migratetype, alloc_flags); } while (page && check_new_pages(page, order)); - spin_unlock(&zone->lock); if (!page) goto failed; + __mod_zone_freepage_state(zone, -(1 << order), get_pcppage_migratetype(page)); + spin_unlock_irqrestore(&zone->lock, flags); __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone, 1); - local_irq_restore(flags); out: /* Separate test+clear to avoid unnecessary atomics */ @@ -3596,7 +3596,7 @@ struct page *rmqueue(struct zone *preferred_zone, return page; failed: - local_irq_restore(flags); + spin_unlock_irqrestore(&zone->lock, flags); return NULL; } @@ -5147,11 +5147,11 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, nr_populated++; } + local_unlock_irqrestore(&pagesets.lock, flags); + __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account); zone_statistics(ac.preferred_zoneref->zone, zone, nr_account); - local_unlock_irqrestore(&pagesets.lock, flags); - return nr_populated; failed_irq: