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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1s4uFl-0000000H6iy-2Cag; Thu, 09 May 2024 03:15:29 +0000 Date: Thu, 9 May 2024 04:15:29 +0100 From: Matthew Wilcox To: "zhaoyang.huang" Cc: Andrew Morton , Jens Axboe , Tejun Heo , Josef Bacik , Baolin Wang , linux-mm@kvack.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Zhaoyang Huang , steve.kang@unisoc.com Subject: Re: [RFC PATCH 2/2] mm: introduce budgt control in readahead Message-ID: References: <20240509023937.1090421-1-zhaoyang.huang@unisoc.com> <20240509023937.1090421-3-zhaoyang.huang@unisoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240509023937.1090421-3-zhaoyang.huang@unisoc.com> X-Rspamd-Queue-Id: 79279140007 X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: ptpct7t3n6g3sqbagfkc18qzbz1ihms1 X-HE-Tag: 1715224541-179602 X-HE-Meta: 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 XNGBIFNC ZKGsfMSzls81OUsIa+B9+u5ryX8a/qdc0/KY773CZe/1gtGHTWG24glLgsfnQ81bnLCgP5xLiMIR/Upnwb6bpSsz6JCi1AYwLFqPB6whR8g4XrOvAkXVYBdJaM6Ub0sUkOc7nyOMJGvxUJ2c= 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: List-Subscribe: List-Unsubscribe: On Thu, May 09, 2024 at 10:39:37AM +0800, zhaoyang.huang wrote: > -static unsigned long get_next_ra_size(struct file_ra_state *ra, > +static unsigned long get_next_ra_size(struct readahead_control *ractl, > unsigned long max) > { > - unsigned long cur = ra->size; > + unsigned long cur = ractl->ra->size; > + struct inode *inode = ractl->mapping->host; > + unsigned long budgt = inode->i_sb->s_bdev ? > + blk_throttle_budgt(inode->i_sb->s_bdev) : 0; You can't do this. There's no guarantee that the IO is going to mapping->host->i_sb->s_bdev. You'd have to figure out how to ask the filesystem to get the bdev for the particular range (eg the fs might implement RAID internally).