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 3DE61C41513 for ; Sat, 5 Aug 2023 17:11:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229914AbjHERLP (ORCPT ); Sat, 5 Aug 2023 13:11:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229445AbjHERLN (ORCPT ); Sat, 5 Aug 2023 13:11:13 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 376C1E51 for ; Sat, 5 Aug 2023 10:11:12 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BD91A60C59 for ; Sat, 5 Aug 2023 17:11:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCF1CC433C8; Sat, 5 Aug 2023 17:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1691255471; bh=kIW2ToFnM5JhLxQbr+hFkYlTARFnsrqMHbJ+6K7FJDU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=2XN9wsHU0mB5AAZhW+OTNCDcQ0xanRYZHpbgozUxdNJ2zOBGHeKQ8lXBaHEH9Kj5k Ozp1an1x6HFCggQayOPNoQ3aU+2QP5uX+mm3VRL5FVjfe6Ol1ec7DxRVEjBSl/jqQ1 cuAakzhvsk2U1YWTCde+RradwvVF8dVaZHleZqxs= Date: Sat, 5 Aug 2023 10:11:09 -0700 From: Andrew Morton To: Kemeng Shi Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, baolin.wang@linux.alibaba.com, mgorman@techsingularity.net, david@redhat.com Subject: Re: [PATCH 1/9] mm/compaction: use correct list in move_freelist_{head}/{tail} Message-Id: <20230805101109.740fdc21418d0753c4658df1@linux-foundation.org> In-Reply-To: <20230805110711.2975149-2-shikemeng@huaweicloud.com> References: <20230805110711.2975149-1-shikemeng@huaweicloud.com> <20230805110711.2975149-2-shikemeng@huaweicloud.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 5 Aug 2023 19:07:03 +0800 Kemeng Shi wrote: > The freepage is chained with buddy_list in freelist head. Use buddy_list > instead of lru to correct the list operation. > > ... > > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1395,8 +1395,8 @@ move_freelist_head(struct list_head *freelist, struct page *freepage) > { > LIST_HEAD(sublist); > > - if (!list_is_last(freelist, &freepage->lru)) { > - list_cut_before(&sublist, freelist, &freepage->lru); > + if (!list_is_last(freelist, &freepage->buddy_list)) { > + list_cut_before(&sublist, freelist, &freepage->buddy_list); > list_splice_tail(&sublist, freelist); > } > } > @@ -1412,8 +1412,8 @@ move_freelist_tail(struct list_head *freelist, struct page *freepage) > { > LIST_HEAD(sublist); > > - if (!list_is_first(freelist, &freepage->lru)) { > - list_cut_position(&sublist, freelist, &freepage->lru); > + if (!list_is_first(freelist, &freepage->buddy_list)) { > + list_cut_position(&sublist, freelist, &freepage->buddy_list); > list_splice_tail(&sublist, freelist); > } > } This looks like a significant error. Can we speculate about the possible runtime effects?