From 001281881067a5998384c6669bc8dbbbab8456c4 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 16 Oct 2007 01:24:40 -0700 Subject: mm: use lockless radix-tree probe Probing pages and radix_tree_tagged are lockless operations with the lockless radix-tree. Convert these users to RCU locking rather than using tree_lock. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/readahead.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'mm/readahead.c') diff --git a/mm/readahead.c b/mm/readahead.c index fc52f9f1b80..c5c8981469e 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -149,20 +149,19 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp, /* * Preallocate as many pages as we will need. */ - read_lock_irq(&mapping->tree_lock); for (page_idx = 0; page_idx < nr_to_read; page_idx++) { pgoff_t page_offset = offset + page_idx; if (page_offset > end_index) break; + rcu_read_lock(); page = radix_tree_lookup(&mapping->page_tree, page_offset); + rcu_read_unlock(); if (page) continue; - read_unlock_irq(&mapping->tree_lock); page = page_cache_alloc_cold(mapping); - read_lock_irq(&mapping->tree_lock); if (!page) break; page->index = page_offset; @@ -171,7 +170,6 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp, SetPageReadahead(page); ret++; } - read_unlock_irq(&mapping->tree_lock); /* * Now start the IO. We ignore I/O errors - if the page is not -- cgit v1.2.3