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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2009 Oracle. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
#include "dbinc/log.h"
#include "dbinc/mp.h"
static int __memp_trickle __P((ENV *, int, int *));
/*
* __memp_trickle_pp --
* ENV->memp_trickle pre/post processing.
*
* PUBLIC: int __memp_trickle_pp __P((DB_ENV *, int, int *));
*/
int
__memp_trickle_pp(dbenv, pct, nwrotep)
DB_ENV *dbenv;
int pct, *nwrotep;
{
DB_THREAD_INFO *ip;
ENV *env;
int ret;
env = dbenv->env;
ENV_REQUIRES_CONFIG(env,
env->mp_handle, "memp_trickle", DB_INIT_MPOOL);
ENV_ENTER(env, ip);
REPLICATION_WRAP(env, (__memp_trickle(env, pct, nwrotep)), 0, ret);
ENV_LEAVE(env, ip);
return (ret);
}
/*
* __memp_trickle --
* ENV->memp_trickle.
*/
static int
__memp_trickle(env, pct, nwrotep)
ENV *env;
int pct, *nwrotep;
{
DB_MPOOL *dbmp;
MPOOL *c_mp, *mp;
u_int32_t clean, dirty, i, need_clean, total, dtmp, wrote;
int ret;
dbmp = env->mp_handle;
mp = dbmp->reginfo[0].primary;
if (nwrotep != NULL)
*nwrotep = 0;
if (pct < 1 || pct > 100) {
__db_errx(env,
"DB_ENV->memp_trickle: %d: percent must be between 1 and 100",
pct);
return (EINVAL);
}
/*
* Loop through the caches counting total/dirty buffers.
*
* XXX
* Using hash_page_dirty is our only choice at the moment, but it's not
* as correct as we might like in the presence of pools having more
* than one page size, as a free 512B buffer may not be equivalent to
* having a free 8KB buffer.
*/
for (ret = 0, i = dirty = total = 0; i < mp->nreg; ++i) {
c_mp = dbmp->reginfo[i].primary;
total += c_mp->stat.st_pages;
__memp_stat_hash(&dbmp->reginfo[i], c_mp, &dtmp);
dirty += dtmp;
}
/*
* If there are sufficient clean buffers, no buffers or no dirty
* buffers, we're done.
*/
if (total == 0 || dirty == 0)
return (0);
/*
* The total number of pages is an exact number, but the dirty page
* count can change while we're walking the hash buckets, and it's
* even possible the dirty page count ends up larger than the total
* number of pages.
*/
clean = total > dirty ? total - dirty : 0;
need_clean = (total * (u_int)pct) / 100;
if (clean >= need_clean)
return (0);
need_clean -= clean;
ret = __memp_sync_int(env, NULL,
need_clean, DB_SYNC_TRICKLE | DB_SYNC_INTERRUPT_OK, &wrote, NULL);
STAT((mp->stat.st_page_trickle += wrote));
if (nwrotep != NULL)
*nwrotep = (int)wrote;
return (ret);
}
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