Re: [PATCH v6 07/11] VFS hot tracking: Add a /proc interface to control memory usage

Zhi Yong Wu
2013-12-11T15:44:34Z

Ping ^ 7....

On Wed, Nov 6, 2013 at 9:45 PM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>
> Introduce a /proc interface hot-mem-high-thresh and
> to cap the memory which is consumed by hot_inode_item
> and hot_range_item, and they will be in the unit of
> 1M bytes.
>
> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> ---
> fs/hot_tracking.c | 29 +++++++++++++++++++++++++++++
> fs/hot_tracking.h | 23 +++++++++++++++++++++++
> include/linux/hot_tracking.h | 3 +++
> kernel/sysctl.c | 7 +++++++
> 4 files changed, 62 insertions(+)
>
> diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
> index 7a9bd4f..2c5a7fd 100644
> --- a/fs/hot_tracking.c
> +++ b/fs/hot_tracking.c
> @@ -15,6 +15,7 @@
> #include <linux/sched.h>
> #include "hot_tracking.h"
>
> +int sysctl_hot_mem_high_thresh __read_mostly = 0;
> int sysctl_hot_update_interval __read_mostly = 150;
>
> /* kmem_cache pointers for slab caches */
> @@ -32,6 +33,7 @@ static void hot_range_item_init(struct hot_range_item *hr,
> hr->len = 1 << RANGE_BITS;
> hr->hot_inode = he;
> atomic_long_inc(&he->hot_root->hot_cnt);
> + hot_mem_limit_add(he->hot_root, sizeof(struct hot_range_item));
> }
>
> static void hot_range_item_free_cb(struct rcu_head *head)
> @@ -55,6 +57,7 @@ static void hot_range_item_free(struct kref *kref)
> spin_unlock(&root->m_lock);
>
> atomic_long_dec(&root->hot_cnt);
> + hot_mem_limit_sub(root, sizeof(struct hot_range_item));
> call_rcu(&hr->rcu, hot_range_item_free_cb);
> }
>
> @@ -103,6 +106,8 @@ redo:
> * newly allocated item.
> */
> atomic_long_dec(&he->hot_root->hot_cnt);
> + hot_mem_limit_sub(he->hot_root,
> + sizeof(struct hot_range_item));
> kmem_cache_free(hot_range_item_cachep, hr_new);
> }
> spin_unlock(&he->i_lock);
> @@ -205,6 +210,7 @@ static void hot_inode_item_init(struct hot_inode_item *he,
> he->hot_root = root;
> spin_lock_init(&he->i_lock);
> atomic_long_inc(&root->hot_cnt);
> + hot_mem_limit_add(root, sizeof(struct hot_inode_item));
> }
>
> static void hot_inode_item_free_cb(struct rcu_head *head)
> @@ -226,6 +232,7 @@ static void hot_inode_item_free(struct kref *kref)
> hot_range_tree_free(he);
>
> atomic_long_dec(&he->hot_root->hot_cnt);
> + hot_mem_limit_sub(he->hot_root, sizeof(struct hot_inode_item));
> call_rcu(&he->rcu, hot_inode_item_free_cb);
> }
>
> @@ -272,6 +279,8 @@ redo:
> * newly allocated item.
> */
> atomic_long_dec(&root->hot_cnt);
> + hot_mem_limit_sub(root,
> + sizeof(struct hot_inode_item));
> kmem_cache_free(hot_inode_item_cachep, he_new);
> }
> spin_unlock(&root->t_lock);
> @@ -534,6 +543,23 @@ static unsigned long hot_item_evict(struct hot_info *root, unsigned long work,
> return freed;
> }
>
> +static void hot_mem_evict(struct hot_info *root)
> +{
> + unsigned long sum, thresh;
> +
> + if (sysctl_hot_mem_high_thresh == 0)
> + return;
> +
> + sum = hot_mem_limit_sum(root);
> + /* Note: sysctl_** is in the unit of 1M bytes */
> + thresh = sysctl_hot_mem_high_thresh;
> + thresh *= 1024 * 1024;
> + if (sum <= thresh)
> + return;
> +
> + hot_item_evict(root, sum - thresh, hot_mem_limit_sum);
> +}
> +
> /*
> * Every sync period we update temperatures for
> * each hot inode item and hot range item for aging
> @@ -546,6 +572,8 @@ static void hot_update_worker(struct work_struct *work)
> struct hot_inode_item *he;
> struct rb_node *node;
>
> + hot_mem_evict(root);
> +
> rcu_read_lock();
> node = root->hot_inode_tree.rb_node;
> while (node) {
> @@ -753,6 +781,7 @@ int hot_track_init(struct super_block *sb)
> goto err;
> }
>
> + hot_mem_limit_init(root);
> sb->s_hot_root = root;
> sb->s_flags |= MS_HOTTRACK;
>
> diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
> index 6a6971e..4ee0b90 100644
> --- a/fs/hot_tracking.h
> +++ b/fs/hot_tracking.h
> @@ -46,4 +46,27 @@ struct hot_inode_item *hot_inode_item_lookup(struct hot_info *root, u64 ino);
> void hot_inode_item_unlink(struct inode *inode);
> u32 hot_temp_calc(struct hot_freq *freq);
>
> +/* Memory Tracking Functions. */
> +static inline unsigned long hot_mem_limit_sum(struct hot_info *root)
> +{
> + return atomic_long_read(&root->mem);
> +}
> +
> +static inline void hot_mem_limit_sub(struct hot_info *root,
> + unsigned long count)
> +{
> + atomic_long_sub(count, &root->mem);
> +}
> +
> +static inline void hot_mem_limit_add(struct hot_info *root,
> + unsigned long count)
> +{
> + atomic_long_add(count, &root->mem);
> +}
> +
> +static inline void hot_mem_limit_init(struct hot_info *root)
> +{
> + atomic_long_set(&root->mem, 0);
> +}
> +
> #endif /* __HOT_TRACKING__ */
> diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
> index 43df1b9..5c2c247 100644
> --- a/include/linux/hot_tracking.h
> +++ b/include/linux/hot_tracking.h
> @@ -83,10 +83,13 @@ struct hot_info {
> struct workqueue_struct *update_wq;
> struct delayed_work update_work;
> struct shrinker hot_shrink;
> + atomic_long_t mem;
> };
>
> /* set how often to update temperatures (seconds) */
> extern int sysctl_hot_update_interval;
> +/* note: sysctl_** is in the unit of 1M bytes */
> +extern int sysctl_hot_mem_high_thresh;
>
> /*
> * Hot data tracking ioctls:
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index e0b062a..fde8bc2 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1632,6 +1632,13 @@ static struct ctl_table fs_table[] = {
> .extra1 = &pipe_min_size,
> },
> {
> + .procname = "hot-mem-high-thresh",
> + .data = &sysctl_hot_mem_high_thresh,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> + },
> + {
> .procname = "hot-update-interval",
> .data = &sysctl_hot_update_interval,
> .maxlen = sizeof(int),
> --
> 1.7.11.7
>
> --
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--
Regards,

Zhi Yong Wu