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| author | David S. Miller <davem@davemloft.net> | 2010-01-22 22:45:46 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-01-22 22:45:46 -0800 |
| commit | 6be325719b3e54624397e413efd4b33a997e55a3 (patch) | |
| tree | 57f321a56794cab2222e179b16731e0d76a4a68a /mm/readahead.c | |
| parent | 26d92f9276a56d55511a427fb70bd70886af647a (diff) | |
| parent | 92dcffb916d309aa01778bf8963a6932e4014d07 (diff) | |
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'mm/readahead.c')
| -rw-r--r-- | mm/readahead.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index aa1aa234523..033bc135a41 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -547,5 +547,17 @@ 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); |