> -----Original Message-----
> From: [email protected] <[email protected]> On Behalf Of
> Chao Yu
> Sent: Thursday, October 21, 2021 10:34 PM
> To: 常凤楠 <[email protected]>; [email protected]
> Cc: [email protected]
> Subject: Re: [PATCH v2] f2fs: compress: fix overwrite may reduce compress
> ratio unproperly
>
> On 2021/10/14 21:12, Fengnan Chang wrote:
> > when overwrite only first block of cluster, since cluster is not full,
> > it will call f2fs_write_raw_pages when f2fs_write_multi_pages, and
> > cause the whole cluster become uncompressed eventhough data can be
> compressed.
> > this may will make random write bench score reduce a lot.
> >
> > root# dd if=/dev/zero of=./fio-test bs=1M count=1
> >
> > root# sync
> >
> > root# echo 3 > /proc/sys/vm/drop_caches
> >
> > root# f2fs_io get_cblocks ./fio-test
> >
> > root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct
> > conv=notrunc
> >
> > w/o patch:
> > root# f2fs_io get_cblocks ./fio-test
> > 189
> >
> > w/ patch:
> > root# f2fs_io get_cblocks ./fio-test
> > 192
> >
> > Signed-off-by: Fengnan Chang <[email protected]>
> > ---
> > fs/f2fs/compress.c | 12 ++++++++++++
> > fs/f2fs/data.c | 7 +++++++
> > fs/f2fs/f2fs.h | 1 +
> > 3 files changed, 20 insertions(+)
> >
> > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
> > c1bf9ad4c220..c4f36ead6f17 100644
> > --- a/fs/f2fs/compress.c
> > +++ b/fs/f2fs/compress.c
> > @@ -857,6 +857,18 @@ void f2fs_end_read_compressed_page(struct page
> *page, bool failed,
> > f2fs_decompress_cluster(dic);
> > }
> >
> > +bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec
> > +*pvec, int index)
>
> Fengnan,
>
> It needs add f2fs prefix for non-static symbol to avoid global namespace
> pollution.
>
> Anyway, how about this?
It looks good for me, you can make this as V3.
>
> ---
> fs/f2fs/compress.c | 19 +++++++++++++++++++
> fs/f2fs/data.c | 7 ++++---
> fs/f2fs/f2fs.h | 2 ++
> 3 files changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
> c1bf9ad4c220..15d9b89d4df0 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -881,6 +881,25 @@ bool f2fs_cluster_can_merge_page(struct
> compress_ctx *cc, pgoff_t index)
> return is_page_in_cluster(cc, index);
> }
>
> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
> *pvec,
> + int index, int nr_pages)
> +{
> + unsigned long pgidx;
> + int i;
> +
> + if (nr_pages - index < cc->cluster_size)
> + return false;
> +
> + pgidx = pvec->pages[index]->index;
> +
> + for (i = 1; i < cc->cluster_size; i++) {
> + if (pvec->pages[index + i]->index != pgidx + i)
> + return false;
> + }
> +
> + return true;
> +}
> +
> static bool cluster_has_invalid_data(struct compress_ctx *cc)
> {
> loff_t i_size = i_size_read(cc->inode); diff --git a/fs/f2fs/data.c
> b/fs/f2fs/data.c index 14fe5c6216cc..b0665f69c093 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3075,9 +3075,10 @@ static int f2fs_write_cache_pages(struct
> address_space *mapping,
> done = 1;
> break;
> } else if (ret2 &&
> - !f2fs_compress_write_end(inode,
> - fsdata,
> page->index,
> - 1)) {
> + (!f2fs_compress_write_end(inode,
> + fsdata, page->index, 1)
> ||
> +
> !f2fs_all_cluster_page_loaded(&cc,
> + &pvec, i, nr_pages))) {
> retry = 1;
> break;
> }
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7a32c2127945..b8da34198ce0
> 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4047,6 +4047,8 @@ void f2fs_end_read_compressed_page(struct page
> *page, bool failed,
> block_t blkaddr);
> bool f2fs_cluster_is_empty(struct compress_ctx *cc);
> bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
> *pvec,
> + int index, int nr_pages);
> bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
> void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page
> *page);
> int f2fs_write_multi_pages(struct compress_ctx *cc,
> --
> 2.32.0
>
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