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| author | Nick Piggin <npiggin@suse.de> | 2008-07-25 19:45:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-26 12:00:06 -0700 |
| commit | 30002ed2e41830ec03ec3e577ad83ac6b188f96e (patch) | |
| tree | 13896f3038e391eb41246455239d7678cf51b011 | |
| parent | 652ea695364142b2464744746beac206d050ef19 (diff) | |
| download | lwn-30002ed2e41830ec03ec3e577ad83ac6b188f96e.tar.gz lwn-30002ed2e41830ec03ec3e577ad83ac6b188f96e.zip | |
mm: readahead scan lockless
radix_tree_next_hole() is implemented as a series of radix_tree_lookup()s.
So it can be called locklessly, under rcu_read_lock().
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/readahead.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index d8723a5f6496..77e8ddf945e9 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -382,9 +382,9 @@ ondemand_readahead(struct address_space *mapping, if (hit_readahead_marker) { pgoff_t start; - read_lock_irq(&mapping->tree_lock); - start = radix_tree_next_hole(&mapping->page_tree, offset, max+1); - read_unlock_irq(&mapping->tree_lock); + rcu_read_lock(); + start = radix_tree_next_hole(&mapping->page_tree, offset,max+1); + rcu_read_unlock(); if (!start || start - offset > max) return 0; |