From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: [PATCH v9 03/35] dcache: convert dentry_stat.nr_unused to per-cpu counters Date: Thu, 30 May 2013 14:35:49 +0400 Message-ID: <1369910181-20026-4-git-send-email-glommer@openvz.org> References: <1369910181-20026-1-git-send-email-glommer@openvz.org> Cc: , Mel Gorman , Dave Chinner , , , , Michal Hocko , Johannes Weiner , hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, Greg Thelen , Dave Chinner To: Andrew Morton Return-path: In-Reply-To: <1369910181-20026-1-git-send-email-glommer-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org From: Dave Chinner Before we split up the dcache_lru_lock, the unused dentry counter needs to be made independent of the global dcache_lru_lock. Convert it to per-cpu counters to do this. [ v5: comment about possible cpus ] Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Acked-by: Mel Gorman --- fs/dcache.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index aca4e4b..9f2aa96 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -118,8 +118,10 @@ struct dentry_stat_t dentry_stat = { }; static DEFINE_PER_CPU(long, nr_dentry); +static DEFINE_PER_CPU(long, nr_dentry_unused); #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) +/* scan possible cpus instead of online and avoid worrying about CPU hotplug. */ static long get_nr_dentry(void) { int i; @@ -129,10 +131,20 @@ static long get_nr_dentry(void) return sum < 0 ? 0 : sum; } +static long get_nr_dentry_unused(void) +{ + int i; + long sum = 0; + for_each_possible_cpu(i) + sum += per_cpu(nr_dentry_unused, i); + return sum < 0 ? 0 : sum; +} + int proc_nr_dentry(ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { dentry_stat.nr_dentry = get_nr_dentry(); + dentry_stat.nr_unused = get_nr_dentry_unused(); return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); } #endif @@ -312,7 +324,7 @@ static void dentry_lru_add(struct dentry *dentry) spin_lock(&dcache_lru_lock); list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); dentry->d_sb->s_nr_dentry_unused++; - dentry_stat.nr_unused++; + this_cpu_inc(nr_dentry_unused); spin_unlock(&dcache_lru_lock); } } @@ -322,7 +334,7 @@ static void __dentry_lru_del(struct dentry *dentry) list_del_init(&dentry->d_lru); dentry->d_flags &= ~DCACHE_SHRINK_LIST; dentry->d_sb->s_nr_dentry_unused--; - dentry_stat.nr_unused--; + this_cpu_dec(nr_dentry_unused); } /* @@ -343,7 +355,7 @@ static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list) if (list_empty(&dentry->d_lru)) { list_add_tail(&dentry->d_lru, list); dentry->d_sb->s_nr_dentry_unused++; - dentry_stat.nr_unused++; + this_cpu_inc(nr_dentry_unused); } else { list_move_tail(&dentry->d_lru, list); } -- 1.8.1.4