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 ECAEAC433FE for ; Tue, 22 Nov 2022 13:13:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233610AbiKVNNT (ORCPT ); Tue, 22 Nov 2022 08:13:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233390AbiKVNNH (ORCPT ); Tue, 22 Nov 2022 08:13:07 -0500 Received: from outbound-smtp19.blacknight.com (outbound-smtp19.blacknight.com [46.22.139.246]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 989562654A for ; Tue, 22 Nov 2022 05:13:04 -0800 (PST) Received: from mail.blacknight.com (pemlinmail02.blacknight.ie [81.17.254.11]) by outbound-smtp19.blacknight.com (Postfix) with ESMTPS id 467661C3841 for ; Tue, 22 Nov 2022 13:13:03 +0000 (GMT) Received: (qmail 22136 invoked from network); 22 Nov 2022 13:13:03 -0000 Received: from unknown (HELO morpheus.112glenside.lan) (mgorman@techsingularity.net@[84.203.198.246]) by 81.17.254.9 with ESMTPA; 22 Nov 2022 13:13:02 -0000 From: Mel Gorman To: Andrew Morton Cc: Hugh Dickins , Yu Zhao , Vlastimil Babka , Marcelo Tosatti , Michal Hocko , Marek Szyprowski , LKML , Linux-MM , Mel Gorman Subject: [PATCH 2/2] mm/page_alloc: Simplify locking during free_unref_page_list Date: Tue, 22 Nov 2022 13:12:29 +0000 Message-Id: <20221122131229.5263-3-mgorman@techsingularity.net> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20221122131229.5263-1-mgorman@techsingularity.net> References: <20221122131229.5263-1-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While freeing a large list, the zone lock will be released and reacquired to avoid long hold times since commit c24ad77d962c ("mm/page_alloc.c: avoid excessive IRQ disabled times in free_unref_page_list()"). As suggested by Vlastimil Babka, the lockrelease/reacquire logic can be simplified by reusing the logic that acquires a different lock when changing zones. Signed-off-by: Mel Gorman Reviewed-by: Vlastimil Babka --- mm/page_alloc.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 445066617204..08e32daf0918 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3518,13 +3518,19 @@ void free_unref_page_list(struct list_head *list) list_del(&page->lru); migratetype = get_pcppage_migratetype(page); - /* Different zone, different pcp lock. */ - if (zone != locked_zone) { + /* + * Either different zone requiring a different pcp lock or + * excessive lock hold times when freeing a large list of + * pages. + */ + if (zone != locked_zone || batch_count == SWAP_CLUSTER_MAX) { if (pcp) { pcp_spin_unlock(pcp); pcp_trylock_finish(UP_flags); } + batch_count = 0; + /* * trylock is necessary as pages may be getting freed * from IRQ or SoftIRQ context after an IO completion. @@ -3539,7 +3545,6 @@ void free_unref_page_list(struct list_head *list) continue; } locked_zone = zone; - batch_count = 0; } /* @@ -3551,19 +3556,7 @@ void free_unref_page_list(struct list_head *list) trace_mm_page_free_batched(page); free_unref_page_commit(zone, pcp, page, migratetype, 0); - - /* - * Guard against excessive lock hold times when freeing - * a large list of pages. Lock will be reacquired if - * necessary on the next iteration. - */ - if (++batch_count == SWAP_CLUSTER_MAX) { - pcp_spin_unlock(pcp); - pcp_trylock_finish(UP_flags); - batch_count = 0; - pcp = NULL; - locked_zone = NULL; - } + batch_count++; } if (pcp) { -- 2.35.3