From: Zhengyuan Liu <liuzhengyuan@kylinos.cn> mainline inclusion from mainline-5.3-rc2 commit 9310a7ba6de8cce6209e3e8a3cdf733f824cdd9b category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA --------------------------- We are using PAGE_SIZE as the unit to determine if the total len in async_list has exceeded max_pages, it's not fair for smaller io sizes. For example, if we are doing 1k-size io streams, we will never exceed max_pages since len >>= PAGE_SHIFT always gets zero. So use original bytes to make it more accurate. Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflicts: fs/io_uring.c [ Patch b5420237ec81("mm: refactor readahead defines in mm.h") is not applied. ] Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- fs/io_uring.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 79a38405be68..e027f5bde537 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -202,7 +202,7 @@ struct async_list { struct file *file; off_t io_end; - size_t io_pages; + size_t io_len; }; struct io_ring_ctx { @@ -1157,28 +1157,26 @@ static void io_async_list_note(int rw, struct io_kiocb *req, size_t len) off_t io_end = kiocb->ki_pos + len; if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) { - unsigned long max_pages; + unsigned long max_bytes; /* Use 8x RA size as a decent limiter for both reads/writes */ - max_pages = filp->f_ra.ra_pages; - if (!max_pages) - max_pages = VM_MAX_READAHEAD >> (PAGE_SHIFT - 10); - max_pages *= 8; - - /* If max pages are exceeded, reset the state */ - len >>= PAGE_SHIFT; - if (async_list->io_pages + len <= max_pages) { + max_bytes = filp->f_ra.ra_pages << (PAGE_SHIFT + 3); + if (!max_bytes) + max_bytes = VM_MAX_READAHEAD << 7; + + /* If max len are exceeded, reset the state */ + if (async_list->io_len + len <= max_bytes) { req->flags |= REQ_F_SEQ_PREV; - async_list->io_pages += len; + async_list->io_len += len; } else { io_end = 0; - async_list->io_pages = 0; + async_list->io_len = 0; } } /* New file? Reset state. */ if (async_list->file != filp) { - async_list->io_pages = 0; + async_list->io_len = 0; async_list->file = filp; } async_list->io_end = io_end; -- 2.25.1