Re: [f2fs-dev] [PATCH v9 22/25] f2fs: Convert from readpages to readahead

Jaegeuk Kim
2020-03-23T03:55:19Z

On 03/20, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> Use the new readahead operation in f2fs
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: William Kucharski <william.kucharski@oracle.com>

Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>

> ---
> fs/f2fs/data.c | 47 +++++++++++++++----------------------
> include/trace/events/f2fs.h | 6 ++---
> 2 files changed, 22 insertions(+), 31 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8e9aa2254490..237dff36fe73 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2160,8 +2160,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
> * from read-ahead.
> */
> static int f2fs_mpage_readpages(struct address_space *mapping,
> - struct list_head *pages, struct page *page,
> - unsigned nr_pages, bool is_readahead)
> + struct readahead_control *rac, struct page *page)
> {
> struct bio *bio = NULL;
> sector_t last_block_in_bio = 0;
> @@ -2179,6 +2178,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> .nr_cpages = 0,
> };
> #endif
> + unsigned nr_pages = rac ? readahead_count(rac) : 1;
> unsigned max_nr_pages = nr_pages;
> int ret = 0;
>
> @@ -2192,15 +2192,9 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> map.m_may_create = false;
>
> for (; nr_pages; nr_pages--) {
> - if (pages) {
> - page = list_last_entry(pages, struct page, lru);
> -
> + if (rac) {
> + page = readahead_page(rac);
> prefetchw(&page->flags);
> - list_del(&page->lru);
> - if (add_to_page_cache_lru(page, mapping,
> - page_index(page),
> - readahead_gfp_mask(mapping)))
> - goto next_page;
> }
>
> #ifdef CONFIG_F2FS_FS_COMPRESSION
> @@ -2210,7 +2204,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> ret = f2fs_read_multi_pages(&cc, &bio,
> max_nr_pages,
> &last_block_in_bio,
> - is_readahead);
> + rac);
> f2fs_destroy_compress_ctx(&cc);
> if (ret)
> goto set_error_page;
> @@ -2233,7 +2227,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> #endif
>
> ret = f2fs_read_single_page(inode, page, max_nr_pages, &map,
> - &bio, &last_block_in_bio, is_readahead);
> + &bio, &last_block_in_bio, rac);
> if (ret) {
> #ifdef CONFIG_F2FS_FS_COMPRESSION
> set_error_page:
> @@ -2242,8 +2236,10 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> zero_user_segment(page, 0, PAGE_SIZE);
> unlock_page(page);
> }
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> next_page:
> - if (pages)
> +#endif
> + if (rac)
> put_page(page);
>
> #ifdef CONFIG_F2FS_FS_COMPRESSION
> @@ -2253,16 +2249,15 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> ret = f2fs_read_multi_pages(&cc, &bio,
> max_nr_pages,
> &last_block_in_bio,
> - is_readahead);
> + rac);
> f2fs_destroy_compress_ctx(&cc);
> }
> }
> #endif
> }
> - BUG_ON(pages && !list_empty(pages));
> if (bio)
> __submit_bio(F2FS_I_SB(inode), bio, DATA);
> - return pages ? 0 : ret;
> + return ret;
> }
>
> static int f2fs_read_data_page(struct file *file, struct page *page)
> @@ -2281,28 +2276,24 @@ static int f2fs_read_data_page(struct file *file, struct page *page)
> if (f2fs_has_inline_data(inode))
> ret = f2fs_read_inline_data(inode, page);
> if (ret == -EAGAIN)
> - ret = f2fs_mpage_readpages(page_file_mapping(page),
> - NULL, page, 1, false);
> + ret = f2fs_mpage_readpages(page_file_mapping(page), NULL, page);
> return ret;
> }
>
> -static int f2fs_read_data_pages(struct file *file,
> - struct address_space *mapping,
> - struct list_head *pages, unsigned nr_pages)
> +static void f2fs_readahead(struct readahead_control *rac)
> {
> - struct inode *inode = mapping->host;
> - struct page *page = list_last_entry(pages, struct page, lru);
> + struct inode *inode = rac->mapping->host;
>
> - trace_f2fs_readpages(inode, page, nr_pages);
> + trace_f2fs_readpages(inode, readahead_index(rac), readahead_count(rac));
>
> if (!f2fs_is_compress_backend_ready(inode))
> - return 0;
> + return;
>
> /* If the file has inline data, skip readpages */
> if (f2fs_has_inline_data(inode))
> - return 0;
> + return;
>
> - return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages, true);
> + f2fs_mpage_readpages(rac->mapping, rac, NULL);
> }
>
> int f2fs_encrypt_one_page(struct f2fs_io_info *fio)
> @@ -3784,7 +3775,7 @@ static void f2fs_swap_deactivate(struct file *file)
>
> const struct address_space_operations f2fs_dblock_aops = {
> .readpage = f2fs_read_data_page,
> - .readpages = f2fs_read_data_pages,
> + .readahead = f2fs_readahead,
> .writepage = f2fs_write_data_page,
> .writepages = f2fs_write_data_pages,
> .write_begin = f2fs_write_begin,
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index 67a97838c2a0..d72da4a33883 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -1375,9 +1375,9 @@ TRACE_EVENT(f2fs_writepages,
>
> TRACE_EVENT(f2fs_readpages,
>
> - TP_PROTO(struct inode *inode, struct page *page, unsigned int nrpage),
> + TP_PROTO(struct inode *inode, pgoff_t start, unsigned int nrpage),
>
> - TP_ARGS(inode, page, nrpage),
> + TP_ARGS(inode, start, nrpage),
>
> TP_STRUCT__entry(
> __field(dev_t, dev)
> @@ -1389,7 +1389,7 @@ TRACE_EVENT(f2fs_readpages,
> TP_fast_assign(
> __entry->dev = inode->i_sb->s_dev;
> __entry->ino = inode->i_ino;
> - __entry->start = page->index;
> + __entry->start = start;
> __entry->nrpage = nrpage;
> ),
>
> --
> 2.25.1
>
>
>
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