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Wed, 09 Nov 2022 18:48:26 -0800 (PST) Message-ID: <7113d66a-9792-b026-cece-5c1b21dd989d@gmail.com> Date: Thu, 10 Nov 2022 10:48:24 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH] mm/vmscan: simplify the nr assignment logic for pages to scan To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chao Xu References: <20221109070416.620887-1-Chao.Xu9@zeekrlife.com> <20221109171952.826d991327e07319c5eb8cd3@linux-foundation.org> From: Chao Xu In-Reply-To: <20221109171952.826d991327e07319c5eb8cd3@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668048508; a=rsa-sha256; cv=none; b=SRj+pm+/UdwDoXnflA2lrD5QtKSYsqkyK+QDE/f0UAITjjHtbQPCyCkY3XPu4OmVbaCZvd KKsmUurYkFjJT72e+zTJPvhwJFxO8pMCoDUjdQSfr1vozc8H9Bg3rwRl/9CndBH4MwiKzM 72AVTxnJEW3JIeLzajf5NeBSJOUn/5w= ARC-Authentication-Results: i=1; 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dkim=pass header.d=gmail.com header.s=20210112 header.b=hJj2r8CB; spf=pass (imf16.hostedemail.com: domain of amos.xuchao@gmail.com designates 209.85.210.195 as permitted sender) smtp.mailfrom=amos.xuchao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1668048507-474474 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000660, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 在 2022/11/10 9:19, Andrew Morton 写道: > On Wed, 9 Nov 2022 15:04:16 +0800 Chao Xu wrote: > >> By default the assignment logic of anonymouns or file inactive >> pages and active pages to scan using the same duplicated code >> snippet. To simplify the logic, merge the same part. >> >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -5932,14 +5932,11 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) >> * scan target and the percentage scanning already complete >> */ >> lru = (lru == LRU_FILE) ? LRU_BASE : LRU_FILE; >> - nr_scanned = targets[lru] - nr[lru]; >> - nr[lru] = targets[lru] * (100 - percentage) / 100; >> - nr[lru] -= min(nr[lru], nr_scanned); >> - >> - lru += LRU_ACTIVE; >> - nr_scanned = targets[lru] - nr[lru]; >> - nr[lru] = targets[lru] * (100 - percentage) / 100; >> - nr[lru] -= min(nr[lru], nr_scanned); >> + for ( ; lru <= lru + LRU_ACTIVE; lru++) { > The "lru++" implicitly assumes that LRU_ACTIVE=1. That happens to be > the case, but a more accurate translation of the existing code would > use "lru += LRU_ACTIVE" here, yes? By default the value of LRU_ACTIVE is 1，but if someone change it one day, I use "lru++" maybe facing some exceptions, which is not robust. So I agree with that "lru += LRU_ACTIVE" is appropriate instead of "lru++". I will send a new patch. >> + nr_scanned = targets[lru] - nr[lru]; >> + nr[lru] = targets[lru] * (100 - percentage) / 100; >> + nr[lru] -= min(nr[lru], nr_scanned); >> + } >> >> scan_adjusted = true; >> }