From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933076AbeCMNmT (ORCPT ); Tue, 13 Mar 2018 09:42:19 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:35292 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932229AbeCMN05 (ORCPT ); Tue, 13 Mar 2018 09:26:57 -0400 From: Matthew Wilcox To: Andrew Morton Cc: Matthew Wilcox , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Ryusuke Konishi , linux-nilfs@vger.kernel.org Subject: [PATCH v9 33/61] mm: Convert workingset to XArray Date: Tue, 13 Mar 2018 06:26:11 -0700 Message-Id: <20180313132639.17387-34-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180313132639.17387-1-willy@infradead.org> References: <20180313132639.17387-1-willy@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthew Wilcox We construct a fake XA_STATE and use it to delete the node with xa_store() rather than adding a special function for this unique use case. Signed-off-by: Matthew Wilcox --- include/linux/swap.h | 9 --------- mm/workingset.c | 51 ++++++++++++++++++++++----------------------------- 2 files changed, 22 insertions(+), 38 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index a0ebb5deea2d..dab96af23d96 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -307,15 +307,6 @@ void workingset_update_node(struct xa_node *node); xas_set_update(xas, workingset_update_node); \ } while (0) -/* Returns workingset_update_node() if the mapping has shadow entries. */ -#define workingset_lookup_update(mapping) \ -({ \ - radix_tree_update_node_t __helper = workingset_update_node; \ - if (dax_mapping(mapping) || shmem_mapping(mapping)) \ - __helper = NULL; \ - __helper; \ -}) - /* linux/mm/page_alloc.c */ extern unsigned long totalram_pages; extern unsigned long totalreserve_pages; diff --git a/mm/workingset.c b/mm/workingset.c index bad4e58881cd..564e97bd5934 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -148,7 +148,7 @@ * and activations is maintained (node->inactive_age). * * On eviction, a snapshot of this counter (along with some bits to - * identify the node) is stored in the now empty page cache radix tree + * identify the node) is stored in the now empty page cache * slot of the evicted page. This is called a shadow entry. * * On cache misses for which there are shadow entries, an eligible @@ -162,7 +162,7 @@ /* * Eviction timestamps need to be able to cover the full range of - * actionable refaults. However, bits are tight in the radix tree + * actionable refaults. However, bits are tight in the xarray * entry, and after storing the identifier for the lruvec there might * not be enough left to represent every single actionable refault. In * that case, we have to sacrifice granularity for distance, and group @@ -338,7 +338,7 @@ void workingset_activation(struct page *page) static struct list_lru shadow_nodes; -void workingset_update_node(struct radix_tree_node *node) +void workingset_update_node(struct xa_node *node) { /* * Track non-empty nodes that contain only shadow entries; @@ -370,7 +370,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, local_irq_enable(); /* - * Approximate a reasonable limit for the radix tree nodes + * Approximate a reasonable limit for the nodes * containing shadow entries. We don't need to keep more * shadow entries than possible pages on the active list, * since refault distances bigger than that are dismissed. @@ -385,11 +385,11 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, * worst-case density of 1/8th. Below that, not all eligible * refaults can be detected anymore. * - * On 64-bit with 7 radix_tree_nodes per page and 64 slots + * On 64-bit with 7 xa_nodes per page and 64 slots * each, this will reclaim shadow entries when they consume * ~1.8% of available memory: * - * PAGE_SIZE / radix_tree_nodes / node_entries * 8 / PAGE_SIZE + * PAGE_SIZE / xa_nodes / node_entries * 8 / PAGE_SIZE */ if (sc->memcg) { cache = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid, @@ -398,7 +398,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, cache = node_page_state(NODE_DATA(sc->nid), NR_ACTIVE_FILE) + node_page_state(NODE_DATA(sc->nid), NR_INACTIVE_FILE); } - max_nodes = cache >> (RADIX_TREE_MAP_SHIFT - 3); + max_nodes = cache >> (XA_CHUNK_SHIFT - 3); if (nodes <= max_nodes) return 0; @@ -408,11 +408,11 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, static enum lru_status shadow_lru_isolate(struct list_head *item, struct list_lru_one *lru, spinlock_t *lru_lock, - void *arg) + void *arg) __must_hold(lru_lock) { + XA_STATE(xas, NULL, 0); struct address_space *mapping; - struct radix_tree_node *node; - unsigned int i; + struct xa_node *node; int ret; /* @@ -420,7 +420,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, * the shadow node LRU under the i_pages lock and the * lru_lock. Because the page cache tree is emptied before * the inode can be destroyed, holding the lru_lock pins any - * address_space that has radix tree nodes on the LRU. + * address_space that has nodes on the LRU. * * We can then safely transition to the i_pages lock to * pin only the address_space of the particular node we want @@ -449,25 +449,18 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, goto out_invalid; if (WARN_ON_ONCE(node->count != node->nr_values)) goto out_invalid; - for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { - if (node->slots[i]) { - if (WARN_ON_ONCE(!xa_is_value(node->slots[i]))) - goto out_invalid; - if (WARN_ON_ONCE(!node->nr_values)) - goto out_invalid; - if (WARN_ON_ONCE(!mapping->nrexceptional)) - goto out_invalid; - node->slots[i] = NULL; - node->nr_values--; - node->count--; - mapping->nrexceptional--; - } - } - if (WARN_ON_ONCE(node->nr_values)) - goto out_invalid; + mapping->nrexceptional -= node->nr_values; + xas.xa = node->array; + xas.xa_node = rcu_dereference_protected(node->parent, + lockdep_is_held(&mapping->i_pages.xa_lock)); + xas.xa_offset = node->offset; + xas.xa_update = workingset_update_node; + /* + * We could store a shadow entry here which was the minimum of the + * shadow entries we were tracking ... + */ + xas_store(&xas, NULL); inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM); - __radix_tree_delete_node(&mapping->i_pages, node, - workingset_lookup_update(mapping)); out_invalid: xa_unlock(&mapping->i_pages); -- 2.16.1