diff options
Diffstat (limited to 'mm/readahead.c')
| -rw-r--r-- | mm/readahead.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index aa1aa2345235..fe1a069fb595 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -501,6 +501,12 @@ void page_cache_sync_readahead(struct address_space *mapping, if (!ra->ra_pages) return; + /* be dumb */ + if (filp && (filp->f_mode & FMODE_RANDOM)) { + force_page_cache_readahead(mapping, filp, offset, req_size); + return; + } + /* do read-ahead */ ondemand_readahead(mapping, ra, filp, false, offset, req_size); } @@ -547,5 +553,17 @@ page_cache_async_readahead(struct address_space *mapping, /* do read-ahead */ ondemand_readahead(mapping, ra, filp, true, offset, req_size); + +#ifdef CONFIG_BLOCK + /* + * Normally the current page is !uptodate and lock_page() will be + * immediately called to implicitly unplug the device. However this + * is not always true for RAID conifgurations, where data arrives + * not strictly in their submission order. In this case we need to + * explicitly kick off the IO. + */ + if (PageUptodate(page)) + blk_run_backing_dev(mapping->backing_dev_info, NULL); +#endif } EXPORT_SYMBOL_GPL(page_cache_async_readahead); |