Re: [PATCH v6 12/19] erofs: Convert uncompressed files from readpages to readahead

Gao Xiang
2020-02-19T02:41:17Z

On Mon, Feb 17, 2020 at 10:46:01AM -0800, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> Use the new readahead operation in erofs
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---

It looks good to me, and will test it later as well..

Acked-by: Gao Xiang <gaoxiang25@huawei.com>

Thanks,
Gao Xiang

> fs/erofs/data.c | 39 +++++++++++++-----------------------
> fs/erofs/zdata.c | 2 +-
> include/trace/events/erofs.h | 6 +++---
> 3 files changed, 18 insertions(+), 29 deletions(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index fc3a8d8064f8..82ebcee9d178 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -280,47 +280,36 @@ static int erofs_raw_access_readpage(struct file *file, struct page *page)
> return 0;
> }
>
> -static int erofs_raw_access_readpages(struct file *filp,
> - struct address_space *mapping,
> - struct list_head *pages,
> - unsigned int nr_pages)
> +static void erofs_raw_access_readahead(struct readahead_control *rac)
> {
> erofs_off_t last_block;
> struct bio *bio = NULL;
> - gfp_t gfp = readahead_gfp_mask(mapping);
> - struct page *page = list_last_entry(pages, struct page, lru);
> -
> - trace_erofs_readpages(mapping->host, page, nr_pages, true);
> + struct page *page;
>
> - for (; nr_pages; --nr_pages) {
> - page = list_entry(pages->prev, struct page, lru);
> + trace_erofs_readpages(rac->mapping->host, readahead_index(rac),
> + readahead_count(rac), true);
>
> + readahead_for_each(rac, page) {
> prefetchw(&page->flags);
> - list_del(&page->lru);
>
> - if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
> - bio = erofs_read_raw_page(bio, mapping, page,
> - &last_block, nr_pages, true);
> + bio = erofs_read_raw_page(bio, rac->mapping, page, &last_block,
> + readahead_count(rac), true);
>
> - /* all the page errors are ignored when readahead */
> - if (IS_ERR(bio)) {
> - pr_err("%s, readahead error at page %lu of nid %llu\n",
> - __func__, page->index,
> - EROFS_I(mapping->host)->nid);
> + /* all the page errors are ignored when readahead */
> + if (IS_ERR(bio)) {
> + pr_err("%s, readahead error at page %lu of nid %llu\n",
> + __func__, page->index,
> + EROFS_I(rac->mapping->host)->nid);
>
> - bio = NULL;
> - }
> + bio = NULL;
> }
>
> - /* pages could still be locked */
> put_page(page);
> }
> - DBG_BUGON(!list_empty(pages));
>
> /* the rare case (end in gaps) */
> if (bio)
> submit_bio(bio);
> - return 0;
> }
>
> static int erofs_get_block(struct inode *inode, sector_t iblock,
> @@ -358,7 +347,7 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
> /* for uncompressed (aligned) files and raw access for other files */
> const struct address_space_operations erofs_raw_access_aops = {
> .readpage = erofs_raw_access_readpage,
> - .readpages = erofs_raw_access_readpages,
> + .readahead = erofs_raw_access_readahead,
> .bmap = erofs_bmap,
> };
>
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 80e47f07d946..17f45fcb8c5c 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -1315,7 +1315,7 @@ static int z_erofs_readpages(struct file *filp, struct address_space *mapping,
> struct page *head = NULL;
> LIST_HEAD(pagepool);
>
> - trace_erofs_readpages(mapping->host, lru_to_page(pages),
> + trace_erofs_readpages(mapping->host, lru_to_page(pages)->index,
> nr_pages, false);
>
> f.headoffset = (erofs_off_t)lru_to_page(pages)->index << PAGE_SHIFT;
> diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
> index 27f5caa6299a..bf9806fd1306 100644
> --- a/include/trace/events/erofs.h
> +++ b/include/trace/events/erofs.h
> @@ -113,10 +113,10 @@ TRACE_EVENT(erofs_readpage,
>
> TRACE_EVENT(erofs_readpages,
>
> - TP_PROTO(struct inode *inode, struct page *page, unsigned int nrpage,
> + TP_PROTO(struct inode *inode, pgoff_t start, unsigned int nrpage,
> bool raw),
>
> - TP_ARGS(inode, page, nrpage, raw),
> + TP_ARGS(inode, start, nrpage, raw),
>
> TP_STRUCT__entry(
> __field(dev_t, dev )
> @@ -129,7 +129,7 @@ TRACE_EVENT(erofs_readpages,
> TP_fast_assign(
> __entry->dev = inode->i_sb->s_dev;
> __entry->nid = EROFS_I(inode)->nid;
> - __entry->start = page->index;
> + __entry->start = start;
> __entry->nrpage = nrpage;
> __entry->raw = raw;
> ),
> --
> 2.25.0
>
>