Hi Chao,
It seems that we already have a readahed function for node pages,
ra_node_page().
So, we don't make a page list for this, but can use the node_inode's
page cache.
So how about writing ra_node_pages() which use the node_inode's page
cache?
Thanks,
2013-11-22 (금), 15:48 +0800, Chao Yu:
> If cp has no CP_UMOUNT_FLAG, we will read all pages in whole node segment
> one by one, it makes low performance. So let's merge contiguous pages and
> readahead for better performance.
>
> Signed-off-by: Chao Yu <chao2...@samsung.com>
> ---
> fs/f2fs/node.c | 89
> +++++++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 63 insertions(+), 26 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 4ac4150..81e704a 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1572,47 +1572,84 @@ int recover_inode_page(struct f2fs_sb_info *sbi,
> struct page *page)
> return 0;
> }
>
> +/*
> + * ra_sum_pages() merge contiguous pages into one bio and submit.
> + * these pre-readed pages are linked in pages list.
> + */
> +static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
> + int start, int nrpages)
> +{
> + struct page *page;
> + int page_idx = start;
> +
> + for (; page_idx < start + nrpages; page_idx++) {
> + /* alloc temporal page for read node summary info*/
> + page = alloc_page(GFP_NOFS | __GFP_ZERO);
> + if (!page) {
> + struct page *tmp;
> + list_for_each_entry_safe(page, tmp, pages, lru) {
> + list_del(&page->lru);
> + unlock_page(page);
> + __free_pages(page, 0);
> + }
> + return -ENOMEM;
> + }
> +
> + lock_page(page);
> + page->index = page_idx;
> + list_add_tail(&page->lru, pages);
> + }
> +
> + list_for_each_entry(page, pages, lru)
> + submit_read_page(sbi, page, page->index, READ_SYNC);
> +
> + f2fs_submit_read_bio(sbi, READ_SYNC);
> + return 0;
> +}
> +
> int restore_node_summary(struct f2fs_sb_info *sbi,
> unsigned int segno, struct f2fs_summary_block *sum)
> {
> struct f2fs_node *rn;
> struct f2fs_summary *sum_entry;
> - struct page *page;
> + struct page *page, *tmp;
> block_t addr;
> - int i, last_offset;
> -
> - /* alloc temporal page for read node */
> - page = alloc_page(GFP_NOFS | __GFP_ZERO);
> - if (!page)
> - return -ENOMEM;
> - lock_page(page);
> + int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
> + int i, last_offset, nrpages, err = 0;
> + LIST_HEAD(page_list);
>
> /* scan the node segment */
> last_offset = sbi->blocks_per_seg;
> addr = START_BLOCK(sbi, segno);
> sum_entry = &sum->entries[0];
>
> - for (i = 0; i < last_offset; i++, sum_entry++) {
> - /*
> - * In order to read next node page,
> - * we must clear PageUptodate flag.
> - */
> - ClearPageUptodate(page);
> + for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
>
> - if (f2fs_readpage(sbi, page, addr, READ_SYNC))
> - goto out;
> + nrpages = min(last_offset - i, bio_blocks);
> + /* read ahead node pages */
> + err = ra_sum_pages(sbi, &page_list, addr, nrpages);
> + if (err)
> + return err;
>
> - lock_page(page);
> - rn = F2FS_NODE(page);
> - sum_entry->nid = rn->footer.nid;
> - sum_entry->version = 0;
> - sum_entry->ofs_in_node = 0;
> - addr++;
> + list_for_each_entry_safe(page, tmp, &page_list, lru) {
> +
> + lock_page(page);
> + if(PageUptodate(page)) {
> + rn = F2FS_NODE(page);
> + sum_entry->nid = rn->footer.nid;
> + sum_entry->version = 0;
> + sum_entry->ofs_in_node = 0;
> + sum_entry++;
> + } else {
> + err = -EIO;
> + }
> +
> + list_del(&page->lru);
> + unlock_page(page);
> + __free_pages(page, 0);
> + }
> }
> - unlock_page(page);
> -out:
> - __free_pages(page, 0);
> - return 0;
> + return err;
> }
>
> static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
--
Jaegeuk Kim
Samsung
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