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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760512157; bh=UMOggXsmSPLysxqQ4itPauqV7qt745eUMB/nuFIg2w0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=o0Woxrr6d4Kjc2IeLhUM//liDCgTmMC8m7u94P0oWpYw5ZABbIAFXouGwSoLw2PWw 4KQjKaw5riSZy7EgXgKqDGkEvvolojqRU+OxJ/VAVp+05l+0lzxnQEL9BUJH+IKaM0 mnQK9uJXXhnDjcU+tAPck6AavFFL1rNQkArdnlK0VdrUU2q9AWB9XVtnD5UtB1A3yC 485ll3gliB5FsLmL/mS1AAUenJWU1qP3BrCK5JebxppZgfn9yiGBJgbTp8Q7pKXz5z HCmsFNOhxhpw71ayascaMj6JwAV+RM4DnpFUls9VqcHz/CnxQwbUoAw5t/UhcXjLtQ sX5HHK1m7lo1A== Message-ID: Date: Wed, 15 Oct 2025 16:09:13 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] writeback: allow the file system to override MIN_WRITEBACK_PAGES To: Christoph Hellwig , Christian Brauner , Jan Kara , Carlos Maiolino Cc: Andrew Morton , willy@infradead.org, hans.holmberg@wdc.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org References: <20251015062728.60104-1-hch@lst.de> <20251015062728.60104-3-hch@lst.de> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20251015062728.60104-3-hch@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 133FD140007 X-Stat-Signature: 8jg46bao7qrtiffb3k3mwbezfa5cupzz X-HE-Tag: 1760512157-720134 X-HE-Meta: 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 R/y0UM9M vWuPAsD7ZmUDAEiS2K7EBrPV+lgXgN+WKTMwZfuhpbhnUb5VUnkzSFAF43a+EO+5lMAevahX7OV77K/G1GnXjz/4CPpwHCwi1Z5ZJJkEMo6uqVktHa0AacL6emHVtXyWeJwwo72uyXcjHnN2ZDcDgJAAvHmacliPlLzHSkxh0cJ4Ve7LcWn2hmMI9e2qWYjIAqRk5l3Ct05eHpDhbmYOZmZcZl8in3KZl5vHjgkTDy2sUbU0Lqal/arm5qq6pmKZaC9rW2tiXmaVXSot5R0QnsXnmD4nLkx51xSPzFBCQkgZA8PbIN0MlEyEXQyIkJy5dN2WE8DPZNz5WBcQ5ZH1tkb8zbA== 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 2025/10/15 15:27, Christoph Hellwig wrote: > The relatively low minimal writeback size of 4MiB leads means that Removes "leads" in the above. > written back inodes on rotational media are switched a lot. Besides > introducing additional seeks, this also can lead to extreme file > fragmentation on zoned devices when a lot of files are cached relative > to the available writeback bandwidth. > > Add a superblock field that allows the file system to override the > default size. > > Signed-off-by: Christoph Hellwig > diff --git a/include/linux/fs.h b/include/linux/fs.h > index c895146c1444..23f1f10646b7 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1583,6 +1583,7 @@ struct super_block { > > spinlock_t s_inode_wblist_lock; > struct list_head s_inodes_wb; /* writeback inodes */ > + unsigned int s_min_writeback_pages; Given that writeback_chunk_size() returns a long type, maybe this should be a long ? > } __randomize_layout; > > static inline struct user_namespace *i_user_ns(const struct inode *inode) -- Damien Le Moal Western Digital Research