diff options
| -rw-r--r-- | mm/readahead.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index c6ffb76827da..c5b0457415be 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -552,15 +552,23 @@ readit: void page_cache_sync_ra(struct readahead_control *ractl, struct file_ra_state *ra, unsigned long req_count) { - /* no read-ahead */ - if (!ra->ra_pages) - return; + bool do_forced_ra = ractl->file && (ractl->file->f_mode & FMODE_RANDOM); - if (blk_cgroup_congested()) - return; + /* + * Even if read-ahead is disabled, issue this request as read-ahead + * as we'll need it to satisfy the requested range. The forced + * read-ahead will do the right thing and limit the read to just the + * requested range, which we'll set to 1 page for this case. + */ + if (!ra->ra_pages || blk_cgroup_congested()) { + if (!ractl->file) + return; + req_count = 1; + do_forced_ra = true; + } /* be dumb */ - if (ractl->file && (ractl->file->f_mode & FMODE_RANDOM)) { + if (do_forced_ra) { force_page_cache_ra(ractl, ra, req_count); return; } |