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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D192C001DE for ; Tue, 1 Aug 2023 02:36:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0262C2800CB; Mon, 31 Jul 2023 22:36:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F19B02800C8; Mon, 31 Jul 2023 22:36:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E09652800CB; Mon, 31 Jul 2023 22:36:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id CEF852800C8 for ; Mon, 31 Jul 2023 22:36:13 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 9C511120316 for ; Tue, 1 Aug 2023 02:36:13 +0000 (UTC) X-FDA: 81073971426.19.F379EC6 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) by imf09.hostedemail.com (Postfix) with ESMTP id B47FE140009 for ; Tue, 1 Aug 2023 02:36:10 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=none; dmarc=none; spf=none (imf09.hostedemail.com: domain of shikemeng@huaweicloud.com has no SPF policy when checking 45.249.212.56) smtp.mailfrom=shikemeng@huaweicloud.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1690857371; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2+tJo6a/IJdVCXMKxevgQlzZmuAgnQugO/S6yP2AjDk=; b=oMQS4LUBTBBR5M9tHukRLSIGyok//vJgWXmDa17z6zyUQX7Ra2up4+aMnBlpCXuYclUaHA cR1Fahf6WHnoGM7mdsfOUQfTYvoIlen3a0RmpQyIxeh1X8N5lixWY2Z2+W2Bh9dV2aeCcx VGmB9B8sJQRuEwEkYnVa18wrhnoz+jA= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=none; dmarc=none; spf=none (imf09.hostedemail.com: domain of shikemeng@huaweicloud.com has no SPF policy when checking 45.249.212.56) smtp.mailfrom=shikemeng@huaweicloud.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1690857371; a=rsa-sha256; cv=none; b=29eA7LFbVbGLRltbz3o5HMtAeg7H8uxcAHzhjf9S8nGABWaWNDpn0rF/EuS+wqVMe7RpuL TjztLXePOTU/0H8gxvU4DKdHrn9fMTTRGcdN6WwtjoiVRBPD8mvEvgMrcdqIbGK3UOP7HF 110lov5mQnJLrmr+aYJsCabkZxtwUsA= Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4RFK3h0gGQz4f3khZ for ; Tue, 1 Aug 2023 10:36:00 +0800 (CST) Received: from [10.174.178.129] (unknown [10.174.178.129]) by APP1 (Coremail) with SMTP id cCh0CgBXsRuRb8hkTSf1OQ--.1427S2; Tue, 01 Aug 2023 10:36:02 +0800 (CST) Subject: Re: [PATCH 1/8] mm/compaction: avoid missing last page block in section after skip offline sections From: Kemeng Shi To: Baolin Wang , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mgorman@techsingularity.net, willy@infradead.org, david@redhat.com References: <20230728171037.2219226-1-shikemeng@huaweicloud.com> <20230728171037.2219226-2-shikemeng@huaweicloud.com> <6e76323f-a1cc-7d20-676e-4eccdbcf6b91@linux.alibaba.com> <9b207dbf-1652-4851-7c6e-16220d5f2f3b@huaweicloud.com> Message-ID: Date: Tue, 1 Aug 2023 10:36:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <9b207dbf-1652-4851-7c6e-16220d5f2f3b@huaweicloud.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-CM-TRANSID:cCh0CgBXsRuRb8hkTSf1OQ--.1427S2 X-Coremail-Antispam: 1UD129KBjvJXoWxCw1kCw48Jry3uw1rCw1xXwb_yoW5tFyrpr yxJFy2gryDG348Wa4xtw1kuryjyws5Ga1UXr47JF18AF1DXFn2gFyqqr1q9ryjgrWxAFyU Zr40yFW7Zr17A37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUk0b4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxk0xIA0c2IEe2xFo4CEbIxvr21l42xK82IYc2Ij 64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x 8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE 2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42 xK8VAvwI8IcIk0rVWrJr0_WFyUJwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv 6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUrR6zUUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected X-Rspam-User: X-Stat-Signature: cqgg5eqzakmx8gg6n36ochj4nt7rqygg X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B47FE140009 X-HE-Tag: 1690857370-768991 X-HE-Meta: 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 AtSMSiDt XiONzf9qwqlDZAXvstSejbEIb1vJarPom86pQZco1iPS+mOOcZuQNu8v+2ytm6Zc932Vo4Kb9T8FHe8EplrbKAvgBDgBG98FnI1wLsax/uC9HxX1xfnpMETrvHtMZRwoKcHNWNTb7MPF4mOyVM0somqk0dn2blnV87sEEEgKORkPOK3tyKDHwmF+HDMevKDnBrfvKVp4S29yBI5jJRvIfnJyhDlrGrsFsZs0F0XOx94NWmZ4t+EOu6nMK9A== 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: on 8/1/2023 10:18 AM, Kemeng Shi wrote: > > > on 7/31/2023 8:01 PM, Baolin Wang wrote: >> >> >> On 7/29/2023 1:10 AM, Kemeng Shi wrote: >>> skip_offline_sections_reverse will return the last pfn in found online >>> section. Then we set block_start_pfn to start of page block which >>> contains the last pfn in section. Then we continue, move one page >>> block forward and ignore the last page block in the online section. >>> Make block_start_pfn point to first page block after online section to fix >>> this: >>> 1. make skip_offline_sections_reverse return end pfn of online section, >>> i.e. pfn of page block after online section. >>> 2. assign block_start_pfn with next_pfn. >>> >>> Fixes: f63224525309 ("mm: compaction: skip the memory hole rapidly when isolating free pages") >>> Signed-off-by: Kemeng Shi >>> --- >>>   mm/compaction.c | 5 ++--- >>>   1 file changed, 2 insertions(+), 3 deletions(-) >>> >>> diff --git a/mm/compaction.c b/mm/compaction.c >>> index 9b7a0a69e19f..ce7841363b12 100644 >>> --- a/mm/compaction.c >>> +++ b/mm/compaction.c >>> @@ -259,7 +259,7 @@ static unsigned long skip_offline_sections_reverse(unsigned long start_pfn) >>>         while (start_nr-- > 0) { >>>           if (online_section_nr(start_nr)) >>> -            return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION - 1; >>> +            return section_nr_to_pfn(start_nr + 1); >> >> This is incorrect, you returned the start pfn of this section. >> >>>       } >>>         return 0; >>> @@ -1670,8 +1670,7 @@ static void isolate_freepages(struct compact_control *cc) >>>                 next_pfn = skip_offline_sections_reverse(block_start_pfn); >>>               if (next_pfn) >>> -                block_start_pfn = max(pageblock_start_pfn(next_pfn), >>> -                              low_pfn); >>> +                block_start_pfn = max(next_pfn, low_pfn); >> >> 'block_start_pfn' should be pageblock aligned. If the 'next_pfn' is not pageblock-aligned (though this is not the common case), we should skip it. >> >> But if the 'next_pfn' is pageblock-aligned, yes, the commit f63224525309 still ignores the last pageblock, which is not right. So I think it should be: >> block_start_pfn = pageblock_aligned(next_pfn) ? : pageblock_start_pfn(next_pfn); >> block_start_pfn = max(block_start_pfn, low_pfn); >> > Hi Baolin, thanks for reply! As skip_offline_sections_reverse is based > on skip_offline_sections. I make the assumption that section is pageblock > aligned based on that we use section start from skip_offline_sections as > block_start_fpn without align check. > If section size is not pageblock aligned in real world, the pageblock aligned > check should be added to skip_offline_sections and skip_offline_sections_reverse. > If no one is against this, I will fix this in next version. THanks! > More information of aligment of section. For powerpc arch, we have SECTION_SIZE_BITS with 24 while PAGE_SHIFT could be configured to 18. Pageblock order is (18 + MAX_ORDER) which coule be 28 and is > SECTION_SZIE_BITS 24, then section start is not aligned with pageblock size. Please correct me if I miss anything. Thanks! -- Best wishes Kemeng Shi