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c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1689558460; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4qhGA1nfyyHNgU4WjcENKwrSx+h/sclZTpD9nsrZJFU=; b=cm7N9AwhLyj5XwpUCyxpKsYntyhMXD6l/lmWPdqm5KuZ+oYGPL9JtZZNdsIqu/fUlHEYjM vgRST+EeplWrcohXyBF5LQ4ZkrXbodc7ScbQPpP//fgNd13wSYSochXUUoVRkSa1XYFbpu UCSF81K0gRSPIcrbkhtlifSsYexWfHg= Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4R44hh6gK3z4f3l1s for ; Mon, 17 Jul 2023 09:47:32 +0800 (CST) Received: from [10.174.178.129] (unknown [10.174.178.129]) by APP4 (Coremail) with SMTP id gCh0CgC3Z6udnbRkEECWOA--.220S2; Mon, 17 Jul 2023 09:47:33 +0800 (CST) Subject: Re: [PATCH 2/3] mm/page_ext: remove rollback for untouched mem_section in online_page_ext To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230714114749.1743032-1-shikemeng@huaweicloud.com> <20230714114749.1743032-3-shikemeng@huaweicloud.com> <20230714105422.648d17f9ba6141f26e469423@linux-foundation.org> From: Kemeng Shi Message-ID: Date: Mon, 17 Jul 2023 09:47:08 +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: <20230714105422.648d17f9ba6141f26e469423@linux-foundation.org> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: 7bit X-CM-TRANSID:gCh0CgC3Z6udnbRkEECWOA--.220S2 X-Coremail-Antispam: 1UD129KBjvdXoWruF1UGF1xCr1rZFWfWFyxuFg_yoWkAFb_Ja 1Sv3WkXw4jqFnxtFWDtwn7XFnrWrWkCw1jgF1kGw4YyFyfJ395Cw1DtrnxXr1kXr4avr9F kws3ur4vqry2qjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbzAYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwV A0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x02 67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0VAS07AlzVAYIcxG8wCF04k20xvY0x0E wIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E74 80Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jrv_JF1lIxkGc2Ij64vIr41lIxAIcVC0 I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF04 k26cxKx2IYs7xG6rW3Jr0E3s1lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY 1x0267AKxVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjxUzsqWUUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 407DA140006 X-Stat-Signature: 3s9d935gtyroci6983ixiic7q9ngccf1 X-Rspam-User: X-HE-Tag: 1689558458-170707 X-HE-Meta: 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 bbOpjyFE fOf+yy8k6y4NIqJhUaxveier86RBVgXbIBVytb4mrA+KN35dI4FqPylxFN04ZBkM6dwexnq9ubtCJjmTkwNt8Il5q7elW55HR89LTqDuRBAPTNR333uZxQ86Pt+QLAGMahQLk7TxGg0nm4q9CK/j3CAuHv5L9K5aR1+KMkbqIjMMpXL2zNAOg4ibcOMqP/0ZjsBsBBAMDcqxGs5m18SLGRbAWPd3vJkZ0+HPLV3389J7AZpX+m24yOKkz0Q+HGpxjWrPgCTX2ATGZTyHQA/8kHbrSUV33OdGlbEf6 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 7/15/2023 1:54 AM, Andrew Morton wrote: > On Fri, 14 Jul 2023 19:47:48 +0800 Kemeng Shi wrote: > >> If init_section_page_ext failed, we only need rollback for mem_section >> before failed mem_section. Make rollback end point to failed mem_section >> to remove unnecessary rollback. >> >> As pfn += PAGES_PER_SECTION will be executed even if init_section_page_ext >> failed. So pfn points to mem_section after failed mem_section. Subtract >> one mem_section from pfn to get failed mem_section. >> >> ... >> >> --- a/mm/page_ext.c >> +++ b/mm/page_ext.c >> @@ -424,6 +424,7 @@ static int __meminit online_page_ext(unsigned long start_pfn, >> return 0; >> >> /* rollback */ >> + end = pfn - PAGES_PER_SECTION; >> for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) >> __free_page_ext(pfn); >> > > This is a bugfix, yes? > > I guess init_section_page_ext() never fails for anyone... I marked this as cleanup because __free_page_ext can handle NULL page_ext from uninitialized mem_section. Then no real bug will be triggered even if init_section_page_ext failed. -- Best wishes Kemeng Shi