diff options
author | Matthew Wilcox <willy@linux.intel.com> | 2016-03-17 14:22:03 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-17 15:09:34 -0700 |
commit | 2cf938aae17203426a89b5955bd1c9668657bfa8 (patch) | |
tree | df3afed25409565778e49995541fabf6f083672d /mm | |
parent | c28f2420635b7000f7b9cde6cdbe6e7a0f8beed1 (diff) | |
download | op-kernel-dev-2cf938aae17203426a89b5955bd1c9668657bfa8.zip op-kernel-dev-2cf938aae17203426a89b5955bd1c9668657bfa8.tar.gz |
mm: use radix_tree_iter_retry()
Instead of a 'goto restart', we can now use radix_tree_iter_retry() to
restart from our current position. This will make a difference when
there are more ways to happen across an indirect pointer. And it
eliminates some confusing gotos.
[vbabka@suse.cz: remove now-obsolete-and-misleading comment]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/filemap.c | 53 | ||||
-rw-r--r-- | mm/shmem.c | 23 |
2 files changed, 29 insertions, 47 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 084ad0f..7c00f10 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1255,7 +1255,6 @@ unsigned find_get_entries(struct address_space *mapping, return 0; rcu_read_lock(); -restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { struct page *page; repeat: @@ -1263,8 +1262,10 @@ repeat: if (unlikely(!page)) continue; if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) - goto restart; + if (radix_tree_deref_retry(page)) { + slot = radix_tree_iter_retry(&iter); + continue; + } /* * A shadow entry of a recently evicted page, a swap * entry from shmem/tmpfs or a DAX entry. Return it @@ -1317,7 +1318,6 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, return 0; rcu_read_lock(); -restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { struct page *page; repeat: @@ -1327,13 +1327,8 @@ repeat: if (radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { - /* - * Transient condition which can only trigger - * when entry at index 0 moves out of or back - * to root: none yet gotten, safe to restart. - */ - WARN_ON(iter.index); - goto restart; + slot = radix_tree_iter_retry(&iter); + continue; } /* * A shadow entry of a recently evicted page, @@ -1384,7 +1379,6 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, return 0; rcu_read_lock(); -restart: radix_tree_for_each_contig(slot, &mapping->page_tree, &iter, index) { struct page *page; repeat: @@ -1395,12 +1389,8 @@ repeat: if (radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { - /* - * Transient condition which can only trigger - * when entry at index 0 moves out of or back - * to root: none yet gotten, safe to restart. - */ - goto restart; + slot = radix_tree_iter_retry(&iter); + continue; } /* * A shadow entry of a recently evicted page, @@ -1460,7 +1450,6 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, return 0; rcu_read_lock(); -restart: radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, *index, tag) { struct page *page; @@ -1471,12 +1460,8 @@ repeat: if (radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { - /* - * Transient condition which can only trigger - * when entry at index 0 moves out of or back - * to root: none yet gotten, safe to restart. - */ - goto restart; + slot = radix_tree_iter_retry(&iter); + continue; } /* * A shadow entry of a recently evicted page. @@ -1539,7 +1524,6 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start, return 0; rcu_read_lock(); -restart: radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, start, tag) { struct page *page; @@ -1549,12 +1533,8 @@ repeat: continue; if (radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { - /* - * Transient condition which can only trigger - * when entry at index 0 moves out of or back - * to root: none yet gotten, safe to restart. - */ - goto restart; + slot = radix_tree_iter_retry(&iter); + continue; } /* @@ -2171,10 +2151,11 @@ repeat: if (unlikely(!page)) goto next; if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) - break; - else - goto next; + if (radix_tree_deref_retry(page)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + goto next; } if (!page_cache_get_speculative(page)) @@ -383,13 +383,10 @@ restart: page = radix_tree_deref_slot(slot); - /* - * This should only be possible to happen at index 0, so we - * don't need to reset the counter, nor do we risk infinite - * restarts. - */ - if (radix_tree_deref_retry(page)) - goto restart; + if (radix_tree_deref_retry(page)) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (radix_tree_exceptional_entry(page)) swapped++; @@ -1951,8 +1948,10 @@ restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { page = radix_tree_deref_slot(slot); if (!page || radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) - goto restart; + if (radix_tree_deref_retry(page)) { + slot = radix_tree_iter_retry(&iter); + continue; + } } else if (page_count(page) - page_mapcount(page) > 1) { spin_lock_irq(&mapping->tree_lock); radix_tree_tag_set(&mapping->page_tree, iter.index, @@ -2006,8 +2005,10 @@ restart: page = radix_tree_deref_slot(slot); if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) - goto restart; + if (radix_tree_deref_retry(page)) { + slot = radix_tree_iter_retry(&iter); + continue; + } page = NULL; } |