175 lines
4 KiB
C
175 lines
4 KiB
C
/*
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MMAP-Cache - handle aging of mmap objects
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* *****************************************************/
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/** @file mmapcache.c
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** Implementation of caching for currently unused memory mapped file regions
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** @todo development in this area is stalled since 2010
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*/
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#include "include/logging.h"
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#include "lib/safeclib.h"
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#include "backend/mmapcache.h"
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LumieraMMapcache lumiera_mcache = NULL;
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void
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lumiera_mmapcache_new (size_t limit)
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{
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TRACE (mmapcache_dbg);
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lumiera_mcache = lumiera_malloc (sizeof (*lumiera_mcache));
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lumiera_mrucache_init (&lumiera_mcache->cache, lumiera_mmap_destroy_node);
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lumiera_mcache->limit = limit;
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lumiera_mcache->total = 0;
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lumiera_mcache->cached = 0;
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lumiera_mutex_init (&lumiera_mcache->lock, "mmapcache", &NOBUG_FLAG (mutex_dbg), NOBUG_CONTEXT);
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}
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void
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lumiera_mmapcache_delete (void)
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{
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TRACE (mmapcache_dbg);
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if (lumiera_mcache)
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{
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REQUIRE (lumiera_mcache->total == lumiera_mcache->cached, "MMaps still checked out at shutdown");
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lumiera_mrucache_destroy (&lumiera_mcache->cache);
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lumiera_mutex_destroy (&lumiera_mcache->lock, &NOBUG_FLAG (mutex_dbg), NOBUG_CONTEXT);
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free (lumiera_mcache);
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lumiera_mcache = NULL;
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}
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}
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void*
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lumiera_mmapcache_mmap_acquire (void)
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{
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TRACE (mmapcache_dbg);
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void* map = NULL;
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LUMIERA_MUTEX_SECTION (mutex_sync, &lumiera_mcache->lock)
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{
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map = lumiera_mrucache_pop (&lumiera_mcache->cache);
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}
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if (!map)
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{
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map = lumiera_malloc (sizeof (lumiera_mmap));
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TRACE (mmapcache_dbg, "allocated new mmap");
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}
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else
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{
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TRACE (mmapcache_dbg, "Popped mmap from cache");
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}
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return map;
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}
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void
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lumiera_mmapcache_announce (LumieraMMap map)
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{
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TRACE (mmapcache_dbg);
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LUMIERA_MUTEX_SECTION (mutex_sync, &lumiera_mcache->lock)
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{
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lumiera_mcache->total += map->size;
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}
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}
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void
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lumiera_mmapcache_forget (LumieraMMap map)
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{
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TRACE (mmapcache_dbg);
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LUMIERA_MUTEX_SECTION (mutex_sync, &lumiera_mcache->lock)
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{
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if (!llist_is_empty (&map->cachenode))
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{
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TODO ("cached stats");
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REQUIRE (llist_is_member (&lumiera_mcache->cache.cache_list, &map->cachenode), "Map object not in cache");
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llist_unlink (&map->cachenode);
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}
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lumiera_mcache->total -= map->size;
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}
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}
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#if 0
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int
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lumiera_mmapcache_age (void)
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{
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TRACE (mmapcache_dbg);
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int ret = 0;
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LUMIERA_MUTEX_SECTION (mmapcache, &lumiera_mcache->lock)
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{
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ret = lumiera_mrucache_age (&lumiera_mcache->cache, 10); TODO ("age nelem == 20%(configurable) of the cache");
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}
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return ret;
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}
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#endif
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LumieraMMap
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lumiera_mmapcache_checkout (LumieraMMap handle)
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{
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TRACE (mmapcache_dbg);
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REQUIRE (handle->refcnt == 0);
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LUMIERA_MUTEX_SECTION (mutex_sync, &lumiera_mcache->lock)
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{
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////////////////////TODO cached stats
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lumiera_mrucache_checkout (&lumiera_mcache->cache, &handle->cachenode);
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}
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return handle;
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}
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void
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lumiera_mmapcache_checkin (LumieraMMap handle)
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{
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TRACE (mmapcache_dbg);
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REQUIRE (handle->refcnt == 0);
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LUMIERA_MUTEX_SECTION (mutex_sync, &lumiera_mcache->lock)
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{
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////////////////////TODO cached stats
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lumiera_mrucache_checkin (&lumiera_mcache->cache, &handle->cachenode);
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}
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}
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/*
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// Local Variables:
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// mode: C
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// c-file-style: "gnu"
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// indent-tabs-mode: nil
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// End:
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*/
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