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d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mRFKMn469rvJhbWPmwRlBDaHdkmhCPJ0BZ8j32mtJZ8=; b=PPG6lWZK5Q8LI8aCN0sufSQLKY2Q19qVslGGYEb1deGV4yvK+dA15b8tS3FNPbDLUJ Z4L8uXFre0khnER2fM4ueexGH1Uey+JFwuMO5nMa4zzxr2XEiIidYHWGgG0pakBPParf +QxU2tNaJr7lUnK3FfVM33/k8W/NCI2ce1FQpYT6H13DdIV1W2PHMdKQcRrD788/KJSv x+jOR2cvD1p48mCdVU9R01NMM9sHlf13VLJ/cP+4RrQF+VbdQVO7PQ7i73ie2+7yBcYe b9AOCAPDWy/1nWPC2Dk0lGSUIXQbokTWMBnSG5GMFwdHGNGU3h36qD5nx0XmVSvy2kT8 BL0Q== X-Gm-Message-State: AOAM531R4oKQr+cSc10izRhZKZkIxXcbhtBwnddsX2x4Dua5/avaa7n2 YEOzmh4ZU+4RauXcagrXCxNcyFfwCbDKrxHeYd0= X-Google-Smtp-Source: ABdhPJz/QfASkB2AoUF3H9HAnFJU6XXHvJ/U1MYXBfXZTb/tYWN+NSY2WoyFrL+ntJxqIizgsyeEfbprGLbH/1tYPAM= X-Received: by 2002:a92:c7ae:: with SMTP id f14mr13948607ilk.39.1597661978616; Mon, 17 Aug 2020 03:59:38 -0700 (PDT) MIME-Version: 1.0 References: <1597395824-3325-1-git-send-email-zhaoyang.huang@unisoc.com> <20200814131034.f71a91c6827904e12a629e04@linux-foundation.org> <20200814211459.65f6db0211872e30684a630a@linux-foundation.org> In-Reply-To: <20200814211459.65f6db0211872e30684a630a@linux-foundation.org> From: Zhaoyang Huang Date: Mon, 17 Aug 2020 18:59:27 +0800 Message-ID: Subject: Re: [PATCH] mm : sync ra->ra_pages with bdi->ra_pages To: Andrew Morton Cc: Roman Gushchin , Zhaoyang Huang , "open list:MEMORY MANAGEMENT" , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 852D018229835 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000091, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Aug 15, 2020 at 12:15 PM Andrew Morton wrote: > > On Fri, 14 Aug 2020 13:10:34 -0700 Andrew Morton wrote: > > > On Fri, 14 Aug 2020 17:03:44 +0800 Zhaoyang Huang wrote: > > > > > Some system(like android) will turbo read during startup via expanding the > > > readahead window and then set it back to normal(128kb as usual). However, some > > > files in the system process context will keep to be opened since it is opened > > > up and has no chance to sync with the updated value as it is almost impossible > > > to change the files attached to the inode(processes are unaware of these things) > > > > How about making VM_READAHEAD_PAGES a variable? > > Or make it settable in Kconfig? I don't think so. The scenario I gave before is a dynamic process, can't be solved via menuconfig thing.