From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Fengnan Chang <changfengnan@vivo.com>
Cc: linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v4] f2fs: compress: avoid unnecessary check in f2fs_prepare_compress_overwrite
Date: Mon, 10 May 2021 08:43:32 -0700 [thread overview]
Message-ID: <YJlUpHJLONlORWWl@google.com> (raw)
In-Reply-To: <20210507094455.1695-1-changfengnan@vivo.com>
On 05/07, Fengnan Chang wrote:
> when write compressed file with O_TRUNC, there will be a lot of
> unnecessary check valid blocks in f2fs_prepare_compress_overwrite,
> especially when written in page size, remove it.
>
> This patch will not bring significant performance improvements, I test
> this on mobile phone, use androbench, the sequential write test case was
> open file with O_TRUNC, set write size to 4KB, performance improved
> about 2%-3%. If write size set to 32MB, performance improved about 0.5%.
>
> Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
> ---
> fs/f2fs/data.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index cf935474ffba..b9ec7b182f45 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3303,9 +3303,17 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
> #ifdef CONFIG_F2FS_FS_COMPRESSION
> if (f2fs_compressed_file(inode)) {
> int ret;
> + pgoff_t end = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
>
> *fsdata = NULL;
>
> + /*
> + * when write pos is bigger than inode size ,f2fs_prepare_compress_overwrite
> + * always return 0, so check pos first to avoid this.
> + */
> + if (index >= end)
> + goto repeat;
What if there're existing clusters beyond i_size? Given performance impacts,
do we really need this?
> +
> ret = f2fs_prepare_compress_overwrite(inode, pagep,
> index, fsdata);
> if (ret < 0) {
> --
> 2.29.0
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next prev parent reply other threads:[~2021-05-10 15:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 9:44 [f2fs-dev] [PATCH v4] f2fs: compress: avoid unnecessary check in f2fs_prepare_compress_overwrite Fengnan Chang
2021-05-10 15:43 ` Jaegeuk Kim [this message]
2021-05-11 11:10 ` [f2fs-dev] 答复: " changfengnan
2021-05-11 21:50 ` Jaegeuk Kim
2021-05-12 1:20 ` Gao Xiang
2021-05-12 1:52 ` Chao Yu
2021-05-13 1:41 ` [f2fs-dev] 答复: " changfengnan
2021-05-13 21:17 ` [f2fs-dev] " Eric Biggers
2021-05-14 1:15 ` Chao Yu
2021-05-17 21:18 ` Eric Biggers
2021-05-18 1:23 ` Chao Yu
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