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quota: Make quota stat accounting lockless.

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Quota stats is mostly writable data structure. Let's alloc percpu
bucket for each value.

NOTE: dqstats_read() function is racy against dqstats_{inc,dec}
and may return inconsistent value. But this is ok since absolute
accuracy is not required.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Dmitry Monakhov
2010-04-26 20:03:33 +04:00
committed by Jan Kara
parent da8d1ba22f
commit dde9588853
4 changed files with 107 additions and 47 deletions
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44
include/linux/quota.h
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@@ -174,6 +174,8 @@ enum {
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/dqblk_xfs.h>
#include <linux/dqblk_v1.h>
@@ -238,19 +240,43 @@ static inline int info_dirty(struct mem_dqinfo *info)
return test_bit(DQF_INFO_DIRTY_B, &info->dqi_flags);
}
struct dqstats {
int lookups;
int drops;
int reads;
int writes;
int cache_hits;
int allocated_dquots;
int free_dquots;
int syncs;
enum {
DQST_LOOKUPS,
DQST_DROPS,
DQST_READS,
DQST_WRITES,
DQST_CACHE_HITS,
DQST_ALLOC_DQUOTS,
DQST_FREE_DQUOTS,
DQST_SYNCS,
_DQST_DQSTAT_LAST
};
struct dqstats {
int stat[_DQST_DQSTAT_LAST];
};
extern struct dqstats *dqstats_pcpu;
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
}
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
}
#define DQ_MOD_B 0 /* dquot modified since read */
#define DQ_BLKS_B 1 /* uid/gid has been warned about blk limit */
#define DQ_INODES_B 2 /* uid/gid has been warned about inode limit */