From: Nick Piggin <npiggin@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Hugh Dickins <hugh@veritas.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>
Subject: [patch 1/6] mm: readahead scan lockless
Date: Sun, 11 Nov 2007 09:47:17 +0100 [thread overview]
Message-ID: <20071111084717.GD19816@wotan.suse.de> (raw)
In-Reply-To: <20071111084556.GC19816@wotan.suse.de>
This can actually go upstream now...
--
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>
---
Index: linux-2.6/mm/readahead.c
===================================================================
--- linux-2.6.orig/mm/readahead.c
+++ linux-2.6/mm/readahead.c
@@ -376,9 +376,9 @@ ondemand_readahead(struct address_space
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;
--
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next prev parent reply other threads:[~2007-11-11 8:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-11 8:45 [patch 0/6] lockless pagecache Nick Piggin
2007-11-11 8:47 ` Nick Piggin [this message]
2007-11-11 8:49 ` [patch 2/6] radix-tree: gang_lookup_slot Nick Piggin
2007-11-11 8:50 ` [patch 3/6] mm: speculative get page Nick Piggin
2007-11-12 20:21 ` Christoph Lameter
2007-11-13 0:35 ` Nick Piggin
2007-11-13 0:37 ` Christoph Lameter
2007-11-13 0:51 ` Nick Piggin
2007-11-11 8:51 ` [patch 4/6] mm: lockless pagecache lookups Nick Piggin
2007-11-11 8:51 ` [patch 5/6] mm: spinlock tree_lock Nick Piggin
2007-11-11 8:52 ` [patch 6/6] mm: speculative refcount debug Nick Piggin
2007-11-17 9:48 ` [patch 0/6] lockless pagecache Peter Zijlstra
2007-11-17 20:16 ` Hugh Dickins
2007-11-19 22:58 ` Nick Piggin
2008-01-09 15:45 ` Peter Zijlstra
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