linux-kernel - [PATCH v1 hot_track 11/18] vfs: register one shrinker

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1352365285-32419-12-git-send-email-zwu.kernel@gmail.com>
Date:	Thu,  8 Nov 2012 17:01:18 +0800
From:	zwu.kernel@...il.com
To:	linux-fsdevel@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, viro@...iv.linux.org.uk,
	david@...morbit.com, cmm@...ibm.com, swhiteho@...hat.com,
	dave@...os.cz, darrick.wong@...cle.com, andi@...stfloor.org,
	northrup.james@...il.com, gregkh@...uxfoundation.org,
	linuxram@...ux.vnet.ibm.com, Zhi Yong Wu <wuzhy@...ux.vnet.ibm.com>
Subject: [PATCH v1 hot_track 11/18] vfs: register one shrinker

From: Zhi Yong Wu <wuzhy@...ux.vnet.ibm.com>

  Register a shrinker to control the amount of
memory that is used in tracking hot regions - if we are throwing
inodes out of memory due to memory pressure, we most definitely are
going to need to reduce the amount of memory the tracking code is
using, even if it means losing useful information (i.e. the shrinker
accelerates the aging process).

Signed-off-by: Zhi Yong Wu <wuzhy@...ux.vnet.ibm.com>
---
 fs/hot_tracking.c            |   61 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/hot_tracking.h |    1 +
 2 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 06127cf..3d96512 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -648,6 +648,61 @@ err:
 }
 EXPORT_SYMBOL_GPL(hot_cache_init);
 
+static int hot_track_prune_map(struct hot_map_head *map_head,
+				bool type, int nr)
+{
+	struct hot_comm_item *node;
+	int i;
+
+	for (i = 0; i < HEAT_MAP_SIZE; i++) {
+		while (!list_empty(&(map_head + i)->node_list)) {
+			if (nr-- <= 0)
+				break;
+
+			node = list_first_entry(&(map_head + i)->node_list,
+					struct hot_comm_item, n_list);
+			if (type) {
+				struct hot_inode_item *hot_inode =
+					container_of(node,
+					struct hot_inode_item, hot_inode);
+				hot_inode_item_put(hot_inode);
+			} else {
+				struct hot_range_item *hot_range =
+					container_of(node,
+					struct hot_range_item, hot_range);
+				hot_range_item_put(hot_range);
+			}
+		}
+	}
+
+	return nr;
+}
+
+/* The shrinker callback function */
+static int hot_track_prune(struct shrinker *shrink,
+			struct shrink_control *sc)
+{
+	struct hot_info *root =
+		container_of(shrink, struct hot_info, hot_shrink);
+	int ret;
+
+	if (sc->nr_to_scan == 0)
+		return root->hot_map_nr;
+
+	if (!(sc->gfp_mask & __GFP_FS))
+		return -1;
+
+	ret = hot_track_prune_map(root->heat_range_map,
+				false, sc->nr_to_scan);
+	if (ret > 0)
+		ret = hot_track_prune_map(root->heat_inode_map,
+					true, ret);
+	if (ret > 0)
+		root->hot_map_nr -= (sc->nr_to_scan - ret);
+
+	return root->hot_map_nr;
+}
+
 /*
  * Main function to update access frequency from read/writepage(s) hooks
  */
@@ -745,6 +800,11 @@ int hot_track_init(struct super_block *sb)
 	queue_delayed_work(root->update_wq, &root->update_work,
 		msecs_to_jiffies(HEAT_UPDATE_DELAY * MSEC_PER_SEC));
 
+	/* Register a shrinker callback */
+	root->hot_shrink.shrink = hot_track_prune;
+	root->hot_shrink.seeks = DEFAULT_SEEKS;
+	register_shrinker(&root->hot_shrink);
+
 	printk(KERN_INFO "VFS: Turning on hot data tracking\n");
 
 	return 0;
@@ -761,6 +821,7 @@ void hot_track_exit(struct super_block *sb)
 {
 	struct hot_info *root = sb->s_hot_root;
 
+	unregister_shrinker(&root->hot_shrink);
 	cancel_delayed_work_sync(&root->update_work);
 	destroy_workqueue(root->update_wq);
 	hot_map_exit(root);
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 67fc0bf..43d9b53 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -104,6 +104,7 @@ struct hot_info {
 	struct workqueue_struct *update_wq;
 	struct delayed_work update_work;
 	struct hot_type *hot_type;
+	struct shrinker hot_shrink;
 };
 
 extern void __init hot_cache_init(void);
-- 
1.7.6.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/