The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.20.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.20.14
------>
commit 851cef04ceb68f61f95e03314e8008afb75b8113
Author: Andrey Ryabinin <aryabi...@virtuozzo.com>
Date: Tue Dec 13 16:48:12 2016 +0400
tcache: speedup tcaches operations on empty tcache
If tcache is empty we can bail out immediately from
tcache_cleancache_[get_page, invalidate_page,invalidate_inode]().
As a fast way of identifying empty tcache this patch adds global atomic
counter of tcache nodes.
https://jira.sw.ru/browse/PSBM-56475
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
Reviewed-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
mm/tcache.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/mm/tcache.c b/mm/tcache.c
index cec5a4e..c7613b2 100644
--- a/mm/tcache.c
+++ b/mm/tcache.c
@@ -98,6 +98,8 @@ struct tcache_pool {
struct tcache_pool_nodeinfo nodeinfo[0];
};
+static atomic_long_t nr_tcache_nodes;
+
/*
* Tcache nodes correspond to inodes. A node is created automatically when a
* new page is added to the cache (cleancache_put_page) and destroyed either
@@ -561,6 +563,7 @@ retry:
node->pool = pool;
node->key = *key;
atomic_long_inc(&pool->nr_nodes);
+ atomic_long_inc(&nr_tcache_nodes);
__tcache_insert_node(&tree->root, node, rb_link, rb_parent);
}
spin_unlock_irqrestore(&tree->lock, flags);
@@ -590,6 +593,7 @@ static void tcache_node_release_fn(struct kref *kref)
__tcache_delete_node(&tree->root, node);
spin_unlock(&tree->lock);
+ atomic_long_dec(&nr_tcache_nodes);
atomic_long_dec(&node->pool->nr_nodes);
kfree(node);
}
@@ -1168,6 +1172,9 @@ static int tcache_cleancache_get_page(int pool_id,
struct tcache_node *node;
struct page *cache_page = NULL;
+ if (!atomic_long_read(&nr_tcache_nodes))
+ return -1;
+
node = tcache_get_node_and_pool(pool_id, &key, false);
if (node) {
cache_page = tcache_detach_page(node, index, true);
@@ -1192,6 +1199,9 @@ static void tcache_cleancache_invalidate_page(int pool_id,
struct tcache_node *node;
struct page *page;
+ if (!atomic_long_read(&nr_tcache_nodes))
+ return;
+
node = tcache_get_node_and_pool(pool_id, &key, false);
if (node) {
page = tcache_detach_page(node, index, false);
@@ -1206,6 +1216,9 @@ static void tcache_cleancache_invalidate_inode(int
pool_id,
{
struct tcache_pool *pool;
+ if (!atomic_long_read(&nr_tcache_nodes))
+ return;
+
pool = tcache_get_pool(pool_id);
if (pool) {
tcache_invalidate_node(pool, &key);
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