diff options
author | Ingo Molnar <mingo@kernel.org> | 2012-12-02 19:56:46 +0000 |
---|---|---|
committer | Mel Gorman <mgorman@suse.de> | 2012-12-11 14:43:00 +0000 |
commit | 5a505085f043e8380f83610f79642853c051e2f1 (patch) | |
tree | c9e86ee196b1ef87350ee9b268a515e2eae4d307 /mm | |
parent | d28d433512f4f387e2563c14db45a7bb8a338b1a (diff) |
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
Convert the struct anon_vma::mutex to an rwsem, which will help
in solving a page-migration scalability problem. (Addressed in
a separate patch.)
The conversion is simple and straightforward: in every case
where we mutex_lock()ed we'll now down_write().
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/huge_memory.c | 4 | ||||
-rw-r--r-- | mm/mmap.c | 8 | ||||
-rw-r--r-- | mm/rmap.c | 22 |
3 files changed, 17 insertions, 17 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 711baf84b153..acd37fe55eb7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1292,7 +1292,7 @@ static int __split_huge_page_splitting(struct page *page, * We can't temporarily set the pmd to null in order * to split it, the pmd must remain marked huge at all * times or the VM won't take the pmd_trans_huge paths - * and it won't wait on the anon_vma->root->mutex to + * and it won't wait on the anon_vma->root->rwsem to * serialize against split_huge_page*. */ pmdp_splitting_flush(vma, address, pmd); @@ -1495,7 +1495,7 @@ static int __split_huge_page_map(struct page *page, return ret; } -/* must be called with anon_vma->root->mutex hold */ +/* must be called with anon_vma->root->rwsem held */ static void __split_huge_page(struct page *page, struct anon_vma *anon_vma) { diff --git a/mm/mmap.c b/mm/mmap.c index 9a796c41e7d9..88408632da66 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2561,15 +2561,15 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) * The LSB of head.next can't change from under us * because we hold the mm_all_locks_mutex. */ - mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem); + down_write(&anon_vma->root->rwsem); /* * We can safely modify head.next after taking the - * anon_vma->root->mutex. If some other vma in this mm shares + * anon_vma->root->rwsem. If some other vma in this mm shares * the same anon_vma we won't take it again. * * No need of atomic instructions here, head.next * can't change from under us thanks to the - * anon_vma->root->mutex. + * anon_vma->root->rwsem. */ if (__test_and_set_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) @@ -2671,7 +2671,7 @@ static void vm_unlock_anon_vma(struct anon_vma *anon_vma) * * No need of atomic instructions here, head.next * can't change from under us until we release the - * anon_vma->root->mutex. + * anon_vma->root->rwsem. */ if (!__test_and_clear_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) diff --git a/mm/rmap.c b/mm/rmap.c index 2ee1ef0f317b..6e3ee3b82798 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -24,7 +24,7 @@ * mm->mmap_sem * page->flags PG_locked (lock_page) * mapping->i_mmap_mutex - * anon_vma->mutex + * anon_vma->rwsem * mm->page_table_lock or pte_lock * zone->lru_lock (in mark_page_accessed, isolate_lru_page) * swap_lock (in swap_duplicate, swap_info_get) @@ -37,7 +37,7 @@ * in arch-dependent flush_dcache_mmap_lock, * within bdi.wb->list_lock in __sync_single_inode) * - * anon_vma->mutex,mapping->i_mutex (memory_failure, collect_procs_anon) + * anon_vma->rwsem,mapping->i_mutex (memory_failure, collect_procs_anon) * ->tasklist_lock * pte map lock */ @@ -103,7 +103,7 @@ static inline void anon_vma_free(struct anon_vma *anon_vma) * LOCK should suffice since the actual taking of the lock must * happen _before_ what follows. */ - if (mutex_is_locked(&anon_vma->root->mutex)) { + if (rwsem_is_locked(&anon_vma->root->rwsem)) { anon_vma_lock(anon_vma); anon_vma_unlock(anon_vma); } @@ -219,9 +219,9 @@ static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct struct anon_vma *new_root = anon_vma->root; if (new_root != root) { if (WARN_ON_ONCE(root)) - mutex_unlock(&root->mutex); + up_write(&root->rwsem); root = new_root; - mutex_lock(&root->mutex); + down_write(&root->rwsem); } return root; } @@ -229,7 +229,7 @@ static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct static inline void unlock_anon_vma_root(struct anon_vma *root) { if (root) - mutex_unlock(&root->mutex); + up_write(&root->rwsem); } /* @@ -349,7 +349,7 @@ void unlink_anon_vmas(struct vm_area_struct *vma) /* * Iterate the list once more, it now only contains empty and unlinked * anon_vmas, destroy them. Could not do before due to __put_anon_vma() - * needing to acquire the anon_vma->root->mutex. + * needing to write-acquire the anon_vma->root->rwsem. */ list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) { struct anon_vma *anon_vma = avc->anon_vma; @@ -365,7 +365,7 @@ static void anon_vma_ctor(void *data) { struct anon_vma *anon_vma = data; - mutex_init(&anon_vma->mutex); + init_rwsem(&anon_vma->rwsem); atomic_set(&anon_vma->refcount, 0); anon_vma->rb_root = RB_ROOT; } @@ -457,14 +457,14 @@ struct anon_vma *page_lock_anon_vma(struct page *page) anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON); root_anon_vma = ACCESS_ONCE(anon_vma->root); - if (mutex_trylock(&root_anon_vma->mutex)) { + if (down_write_trylock(&root_anon_vma->rwsem)) { /* * If the page is still mapped, then this anon_vma is still * its anon_vma, and holding the mutex ensures that it will * not go away, see anon_vma_free(). */ if (!page_mapped(page)) { - mutex_unlock(&root_anon_vma->mutex); + up_write(&root_anon_vma->rwsem); anon_vma = NULL; } goto out; @@ -1299,7 +1299,7 @@ out_mlock: /* * We need mmap_sem locking, Otherwise VM_LOCKED check makes * unstable result and race. Plus, We can't wait here because - * we now hold anon_vma->mutex or mapping->i_mmap_mutex. + * we now hold anon_vma->rwsem or mapping->i_mmap_mutex. * if trylock failed, the page remain in evictable lru and later * vmscan could retry to move the page to unevictable lru if the * page is actually mlocked. |