Date:   Thu, 16 Dec 2021 11:36:46 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <chao@kernel.org>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] f2fs: don't drop compressed page cache in
 .{invalidate,release}page
Message-ID: <YbuVTuA5ivCjra40@google.com>
References: <20211216091356.6643-1-chao@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211216091356.6643-1-chao@kernel.org>
Precedence: bulk

On 12/16, Chao Yu wrote:
> For compressed inode, in .{invalidate,release}page, we will call
> f2fs_invalidate_compress_pages() to drop all compressed page cache of
> current inode.
> 
> But we don't need to drop compressed page cache synchronously in
> .invalidatepage, because, all trancation paths of compressed physical
> block has been covered with f2fs_invalidate_compress_page().
> 
> And also we don't need to drop compressed page cache synchronously
> in .releasepage, because, if there is out-of-memory, we can count
> on page cache reclaim on sbi->compress_inode.
> 
> BTW, this patch may fix the issue reported below:
> 
> https://lore.kernel.org/linux-f2fs-devel/20211202092812.197647-1-changfengnan@vivo.com/T/#u

I think this patch makes more sense to me.

> 
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> v2:
> - fix compile error.
>  fs/f2fs/data.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 2737fcc0dbcf..0fc6e0245732 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3528,12 +3528,9 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
>  
>  	clear_page_private_gcing(page);
>  
> -	if (test_opt(sbi, COMPRESS_CACHE)) {
> -		if (f2fs_compressed_file(inode))
> -			f2fs_invalidate_compress_pages(sbi, inode->i_ino);
> -		if (inode->i_ino == F2FS_COMPRESS_INO(sbi))
> -			clear_page_private_data(page);
> -	}
> +	if (test_opt(sbi, COMPRESS_CACHE) &&
> +			inode->i_ino == F2FS_COMPRESS_INO(sbi))
> +		clear_page_private_data(page);
>  
>  	if (page_private_atomic(page))
>  		return f2fs_drop_inmem_page(inode, page);
> @@ -3553,12 +3550,9 @@ int f2fs_release_page(struct page *page, gfp_t wait)
>  		return 0;
>  
>  	if (test_opt(F2FS_P_SB(page), COMPRESS_CACHE)) {
> -		struct f2fs_sb_info *sbi = F2FS_P_SB(page);
>  		struct inode *inode = page->mapping->host;
>  
> -		if (f2fs_compressed_file(inode))
> -			f2fs_invalidate_compress_pages(sbi, inode->i_ino);
> -		if (inode->i_ino == F2FS_COMPRESS_INO(sbi))
> +		if (inode->i_ino == F2FS_COMPRESS_INO(F2FS_I_SB(inode)))
>  			clear_page_private_data(page);
>  	}
>  
> -- 
> 2.32.0