From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD7F3221F3C for ; Tue, 11 Mar 2025 12:00:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741694433; cv=none; b=p7W0nqPEw5QHfjtZfUNIer1C4ODcMjGwh6RLXUOoCZBdoxRv0zmruYrtlGtUnOfXs3KkVm87f8EyCAXEnupRYjwsD7lc1hoOd3YmXMUzwuc4LayZdyd2IgwE984Fy8mt8iqU924DvyDJ91Haq4BPalxDwABzaepQnp6Mcx/02Gk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741694433; c=relaxed/simple; bh=UUkiOgx3l9K4c/V4+FZ1/gOMX9QIDKDarArDS8WEx9M=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=ccZPOM7iHW2tGdr5WQ2AGxd966oJp6MZllaRJBCH8NaP3JTz7zum0zN2N3NCskNd3jKcsoh/9DDOS/bTV5Sii5FR/sXnBz9OdvOCSlEiQxqlQ0/IXFq4LRpDe7wDA4DrMC7HMtXFF17h4MFt8L7JG2CxnGpWhh6WEI/zqg5dMDU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TW2bYuQn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TW2bYuQn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0426C4CEEC; Tue, 11 Mar 2025 12:00:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741694433; bh=UUkiOgx3l9K4c/V4+FZ1/gOMX9QIDKDarArDS8WEx9M=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=TW2bYuQnuLjiIIhKubGCj7e0KKKz/2eN9gynz5I27Ev8DqUTQiUJfySH2UqnuImLn g+zw7sMkPyytdcZUMMEHFB+mN39UyPm8eDm9eRZZvGAbegCfRvoj5qPMsqgnWA9Bna gS1J+FFV6hBsRhnjbxXdkKvNKKG7mQh19QJepnZ1ZA3T1JsG0a6H0QBXNo1MXMyshl EKYTNtLeB1YUgJnkWMn1x9cpWY+XbpvoioeWGJ94O2C8Lew8i2GbjdOwkyYsyaVnx0 H8S5Ch03TTR0UjYV3Amsq2kEmZ/BH7o+BqsXIDW0AgqMiSJ3WK8Ss0YHOJEfxEkVhc lJphfKu5aMasA== Message-ID: <936351d5-e99c-4c5b-bd8b-8d541122f709@kernel.org> Date: Tue, 11 Mar 2025 20:00:28 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Yohan Joung Subject: Re: [PATCH] f2fs: optimize f2fs DIO overwrites To: Yohan Joung , jaegeuk@kernel.org, daeho43@gmail.com References: <20250307145650.568-1-yohan.joung@sk.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250307145650.568-1-yohan.joung@sk.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/7/25 22:56, Yohan Joung wrote: > this is unnecessary when we know we are overwriting already allocated > blocks and the overhead of starting a transaction can be significant > especially for multithreaded workloads doing small writes. Hi Yohan, So you're trying to avoid f2fs_map_lock() in dio write path, right? Thanks, > > Signed-off-by: Yohan Joung > --- > fs/f2fs/data.c | 20 ++++++++++++++++++++ > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 5 ++++- > 3 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 09437dbd1b42..728630037b74 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -4267,6 +4267,26 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > return 0; > } > > +static int f2fs_iomap_overwrite_begin(struct inode *inode, loff_t offset, > + loff_t length, unsigned flags, struct iomap *iomap, > + struct iomap *srcmap) > +{ > + int ret; > + > + /* > + * Even for writes we don't need to allocate blocks, so just pretend > + * we are reading to save overhead of starting a transaction. > + */ > + flags &= ~IOMAP_WRITE; > + ret = f2fs_iomap_begin(inode, offset, length, flags, iomap, srcmap); > + WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED); > + return ret; > +} > + > const struct iomap_ops f2fs_iomap_ops = { > .iomap_begin = f2fs_iomap_begin, > }; > + > +const struct iomap_ops f2fs_iomap_overwrite_ops = { > + .iomap_begin = f2fs_iomap_overwrite_begin, > +}; > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index c6cc2694f9ac..0511ab5ed42a 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -3936,6 +3936,7 @@ void f2fs_destroy_post_read_processing(void); > int f2fs_init_post_read_wq(struct f2fs_sb_info *sbi); > void f2fs_destroy_post_read_wq(struct f2fs_sb_info *sbi); > extern const struct iomap_ops f2fs_iomap_ops; > +extern const struct iomap_ops f2fs_iomap_overwrite_ops; > > static inline struct page *f2fs_find_data_page(struct inode *inode, > pgoff_t index, pgoff_t *next_pgofs) > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 82b21baf5628..bb2fe6dac9b6 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -4985,6 +4985,7 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from, > const ssize_t count = iov_iter_count(from); > unsigned int dio_flags; > struct iomap_dio *dio; > + const struct iomap_ops *iomap_ops = &f2fs_iomap_ops; > ssize_t ret; > > trace_f2fs_direct_IO_enter(inode, iocb, count, WRITE); > @@ -5025,7 +5026,9 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from, > dio_flags = 0; > if (pos + count > inode->i_size) > dio_flags |= IOMAP_DIO_FORCE_WAIT; > - dio = __iomap_dio_rw(iocb, from, &f2fs_iomap_ops, > + else if (f2fs_overwrite_io(inode, pos, count)) > + iomap_ops = &f2fs_iomap_overwrite_ops; > + dio = __iomap_dio_rw(iocb, from, iomap_ops, > &f2fs_iomap_dio_write_ops, dio_flags, NULL, 0); > if (IS_ERR_OR_NULL(dio)) { > ret = PTR_ERR_OR_ZERO(dio);