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authorDmitry Monakhov <dmonakhov@openvz.org>2010-05-26 23:21:58 +0200
committerJan Kara <jack@suse.cz>2010-05-27 18:56:27 +0200
commitf32764bd2bbb6ea003c158b1d276b4dc9f900348 (patch)
tree7fbabde3796a97b8b121349ea76b22b23238230a
parent1513b02c8b537af275ea74fdfb380c618b9e6778 (diff)
quota: Convert quota statistics to generic percpu_counter
Generic per-cpu counter has some memory overhead but it is negligible for modern systems and embedded systems compile without quota support. And code reuse is a good thing. This patch should fix complain from preemptive kernels which was introduced by dde9588853b1bde. [Jan Kara: Fixed patch to work on 32-bit archs as well] Reported-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/quota/dquot.c46
-rw-r--r--include/linux/quota.h16
2 files changed, 17 insertions, 45 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 1ff91314b8a0..531dee651ef7 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -228,10 +228,6 @@ static struct hlist_head *dquot_hash;
struct dqstats dqstats;
EXPORT_SYMBOL(dqstats);
-#ifdef CONFIG_SMP
-struct dqstats *dqstats_pcpu;
-EXPORT_SYMBOL(dqstats_pcpu);
-#endif
static qsize_t inode_get_rsv_space(struct inode *inode);
static void __dquot_initialize(struct inode *inode, int type);
@@ -676,27 +672,10 @@ static void prune_dqcache(int count)
}
}
-static int dqstats_read(unsigned int type)
-{
- int count = 0;
-#ifdef CONFIG_SMP
- int cpu;
- for_each_possible_cpu(cpu)
- count += per_cpu_ptr(dqstats_pcpu, cpu)->stat[type];
- /* Statistics reading is racy, but absolute accuracy isn't required */
- if (count < 0)
- count = 0;
-#else
- count = dqstats.stat[type];
-#endif
- return count;
-}
-
/*
* This is called from kswapd when we think we need some
* more memory
*/
-
static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
{
if (nr) {
@@ -704,7 +683,9 @@ static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
prune_dqcache(nr);
spin_unlock(&dq_list_lock);
}
- return (dqstats_read(DQST_FREE_DQUOTS)/100) * sysctl_vfs_cache_pressure;
+ return ((unsigned)
+ percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS])
+ /100) * sysctl_vfs_cache_pressure;
}
static struct shrinker dqcache_shrinker = {
@@ -2497,11 +2478,11 @@ EXPORT_SYMBOL(dquot_quotactl_ops);
static int do_proc_dqstats(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
-#ifdef CONFIG_SMP
- /* Update global table */
unsigned int type = (int *)table->data - dqstats.stat;
- dqstats.stat[type] = dqstats_read(type);
-#endif
+
+ /* Update global table */
+ dqstats.stat[type] =
+ percpu_counter_sum_positive(&dqstats.counter[type]);
return proc_dointvec(table, write, buffer, lenp, ppos);
}
@@ -2594,7 +2575,7 @@ static ctl_table sys_table[] = {
static int __init dquot_init(void)
{
- int i;
+ int i, ret;
unsigned long nr_hash, order;
printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
@@ -2612,12 +2593,11 @@ static int __init dquot_init(void)
if (!dquot_hash)
panic("Cannot create dquot hash table");
-#ifdef CONFIG_SMP
- dqstats_pcpu = alloc_percpu(struct dqstats);
- if (!dqstats_pcpu)
- panic("Cannot create dquot stats table");
-#endif
- memset(&dqstats, 0, sizeof(struct dqstats));
+ for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
+ ret = percpu_counter_init(&dqstats.counter[i], 0);
+ if (ret)
+ panic("Cannot create dquot stat counters");
+ }
/* Find power-of-two hlist_heads which can fit into allocation */
nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 2789d07c37be..94c1f03b50eb 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -174,8 +174,7 @@ enum {
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
-#include <linux/percpu.h>
-#include <linux/smp.h>
+#include <linux/percpu_counter.h>
#include <linux/dqblk_xfs.h>
#include <linux/dqblk_v1.h>
@@ -254,6 +253,7 @@ enum {
struct dqstats {
int stat[_DQST_DQSTAT_LAST];
+ struct percpu_counter counter[_DQST_DQSTAT_LAST];
};
extern struct dqstats *dqstats_pcpu;
@@ -261,20 +261,12 @@ extern struct dqstats dqstats;
static inline void dqstats_inc(unsigned int type)
{
-#ifdef CONFIG_SMP
- per_cpu_ptr(dqstats_pcpu, smp_processor_id())->stat[type]++;
-#else
- dqstats.stat[type]++;
-#endif
+ percpu_counter_inc(&dqstats.counter[type]);
}
static inline void dqstats_dec(unsigned int type)
{
-#ifdef CONFIG_SMP
- per_cpu_ptr(dqstats_pcpu, smp_processor_id())->stat[type]--;
-#else
- dqstats.stat[type]--;
-#endif
+ percpu_counter_dec(&dqstats.counter[type]);
}
#define DQ_MOD_B 0 /* dquot modified since read */