Messages in this thread | | | Date | Tue, 9 Nov 2021 11:16:47 +0800 | From | Gao Xiang <> | Subject | Re: [PATCH 2/2] erofs: add sysfs node to control sync decompression strategy |
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On Tue, Nov 09, 2021 at 10:54:45AM +0800, Huang Jianan via Linux-erofs wrote: > Although readpage is a synchronous path, there will be no additional > kworker scheduling overhead in non-atomic contexts. So we can add a > sysfs node to allow disable sync decompression. > > Signed-off-by: Huang Jianan <huangjianan@oppo.com> > --- > fs/erofs/internal.h | 2 +- > fs/erofs/super.c | 2 +- > fs/erofs/sysfs.c | 6 ++++++ > fs/erofs/zdata.c | 9 ++++----- > 4 files changed, 12 insertions(+), 7 deletions(-) > > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > index d0cd712dc222..1ab96878009d 100644 > --- a/fs/erofs/internal.h > +++ b/fs/erofs/internal.h > @@ -60,7 +60,7 @@ struct erofs_mount_opts { > #ifdef CONFIG_EROFS_FS_ZIP > /* current strategy of how to use managed cache */ > unsigned char cache_strategy; > - /* strategy of sync decompression (false - auto, true - force on) */ > + /* strategy of sync decompression (false - disable, true - force on) */
Please leave false - auto.
> bool readahead_sync_decompress; > > /* threshold for decompression synchronously */ > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > index abc1da5d1719..26585d865503 100644 > --- a/fs/erofs/super.c > +++ b/fs/erofs/super.c > @@ -423,7 +423,7 @@ static void erofs_default_options(struct erofs_fs_context *ctx) > #ifdef CONFIG_EROFS_FS_ZIP > ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND; > ctx->opt.max_sync_decompress_pages = 3; > - ctx->opt.readahead_sync_decompress = false; > + ctx->opt.readahead_sync_decompress = true;
Please leave readahead_sync_decompress = false 'auto' by default.
I don't like .readpage() applies async decompression since it's actually a sync way, otherwise, it will cause more scheduling overhead, see: https://lore.kernel.org/r/20201016160443.18685-1-willy@infradead.org https://lore.kernel.org/r/20201102184312.25926-16-willy@infradead.org
Thanks, Gao Xiang
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