Ichthyostega
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Uniform sequence at start of source files - copyright claim - license - file comment - header guard - lumiera includes - library / system includes Lumiera uses Brittish spelling. Add an according note to the styleguide.
131 lines
3.3 KiB
C
131 lines
3.3 KiB
C
/*
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MMAPCACHE.h - 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.h
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** Lumiera's Mmapcache stores a MRU cache of all established mmaped memory regions which are currently not in use.
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** The mmapcache also manages the upper limit about how much memory can be mmaped.
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*/
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#ifndef BACKEND_MMAPCACHE_H
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#define BACKEND_MMAPCACHE_H
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#include "lib/error.h"
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#include "lib/mrucache.h"
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#include "lib/mutex.h"
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typedef struct lumiera_mmapcache_struct lumiera_mmapcache;
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typedef lumiera_mmapcache* LumieraMMapcache;
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#include "backend/mmap.h"
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#include <nobug.h>
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struct lumiera_mmapcache_struct
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{
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lumiera_mrucache cache;
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size_t limit;
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size_t total;
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size_t cached;
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lumiera_mutex lock;
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};
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/**
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* Initialises the mmapcache.
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* @param limit the mmapcache will drop elements when the sum of all mmappings gives over limit
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*/
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void
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lumiera_mmapcache_new (size_t limit);
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/**
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* Delete the mmap cache.
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* No mmaps in the cache must be locked, this would be a fatal error.
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* The handles are closed automatically.
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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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* Get a fresh mmap object.
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* when mmaped_limit is reached, the oldest mmap object gets dropped else
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* a new allocated object is returned
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* @return the new uninitialised mmap (void* because this is uninitialised)
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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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* Announce a new mmap object to the cache quotas.
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* Update the statistics kept in the cache,
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* the map object is still considered to be checked out
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* @param map object to be announced
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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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* Remove a mmap object from the cache quotas.
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* Update the statistics kept in the cache, remove it from the cache.
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* @param map object to be removed
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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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* Destroy and free the nelem oldest elements.
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* Used to free up resources and memory.
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* @return nelem-(number of elements which got freed), that is 0 if all requested elements got freed
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*/
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int
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lumiera_mmapcache_age (void);
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/**
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* Remove a mmap from cache aging
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* Mmaps which are subject of cache aging must be checked out before they can be used.
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* @param handle the mmap to be checked out
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*/
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LumieraMMap
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lumiera_mmapcache_checkout (LumieraMMap handle);
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/**
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* Put a mmap into the cache
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* Mmaps which are checked in are subject of cache aging and might get destroyed and reused.
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* @param handle the mmap to be checked in
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*/
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void
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lumiera_mmapcache_checkin (LumieraMMap handle);
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#endif /*BACKEND_MMAPCACHE_H*/
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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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