From 3dec0ba0be6a532cac949e02b853021bf6d57dad Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 12 Dec 2014 16:54:27 -0800 Subject: [PATCH] mm/rmap: share the i_mmap_rwsem Similarly to the anon memory counterpart, we can share the mapping's lock ownership as the interval tree is not modified when doing doing the walk, only the file page. Signed-off-by: Davidlohr Bueso Acked-by: Rik van Riel Acked-by: "Kirill A. Shutemov" Acked-by: Hugh Dickins Cc: Oleg Nesterov Acked-by: Peter Zijlstra (Intel) Cc: Srikar Dronamraju Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fs.h | 10 ++++++++++ mm/rmap.c | 6 +++--- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 6abcd0b72ae0..1d1838de6882 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -478,6 +478,16 @@ static inline void i_mmap_unlock_write(struct address_space *mapping) up_write(&mapping->i_mmap_rwsem); } +static inline void i_mmap_lock_read(struct address_space *mapping) +{ + down_read(&mapping->i_mmap_rwsem); +} + +static inline void i_mmap_unlock_read(struct address_space *mapping) +{ + up_read(&mapping->i_mmap_rwsem); +} + /* * Might pages of this file be mapped into userspace? */ diff --git a/mm/rmap.c b/mm/rmap.c index 18247f89f1a8..14ad2b3b0f54 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1690,7 +1690,8 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc) if (!mapping) return ret; - i_mmap_lock_write(mapping); + + i_mmap_lock_read(mapping); vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { unsigned long address = vma_address(page, vma); @@ -1711,9 +1712,8 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc) goto done; ret = rwc->file_nonlinear(page, mapping, rwc->arg); - done: - i_mmap_unlock_write(mapping); + i_mmap_unlock_read(mapping); return ret; } -- 2.20.1