e938b36071
Quite some code which was hold back in favor of the config and plugin stuff implements: * mmapcache: mru cache for unused memory mappings * mmap: single mmaped areas * mmapings: manages mmaps established for one filedescriptor
158 lines
3.6 KiB
C
158 lines
3.6 KiB
C
/*
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mmapings.c - manage ranges of mmaped areas on a filedescriptor
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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 the
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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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#include "lib/mutex.h"
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#include "lib/safeclib.h"
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#include "backend/mmapings.h"
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#include "backend/mmapcache.h"
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/**
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* @file
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*
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*/
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NOBUG_DEFINE_FLAG_PARENT (mmapings, mmap_all);
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LumieraMMapings
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lumiera_mmapings_init (LumieraMMapings self, LumieraFile file, size_t chunksize)
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{
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TRACE (mmapings);
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REQUIRE (!file->descriptor->mmapings);
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llist_init (&self->mmaps);
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self->descriptor = file->descriptor;
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self->chunksize = chunksize;
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lumiera_mutex_init (&self->lock, "mmapings", &NOBUG_FLAG(mmapings));
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return self;
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}
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LumieraMMapings
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lumiera_mmapings_destroy (LumieraMMapings self)
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{
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TRACE (mmapings);
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if (!self)
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return NULL;
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LLIST_WHILE_TAIL (&self->mmaps, node)
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{
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LumieraMMap mmap = LLIST_TO_STRUCTP (node, lumiera_mmap, searchnode);
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lumiera_mmap_delete (mmap);
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}
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lumiera_mutex_destroy (&self->lock, &NOBUG_FLAG(mmapings));
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return self;
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}
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LumieraMMapings
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lumiera_mmapings_new (LumieraFile file, size_t chunksize)
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{
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LumieraMMapings self = lumiera_malloc (sizeof (*self));
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return lumiera_mmapings_init (self, file, chunksize);
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}
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void
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lumiera_mmapings_delete (LumieraMMapings self)
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{
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TRACE (mmapings);
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free (lumiera_mmapings_destroy (self));
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}
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LumieraMMap
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lumiera_mmapings_mmap_acquire (LumieraMMapings self, LumieraFile file, LList acquirer, off_t start, size_t size)
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{
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TRACE (mmapings);
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LumieraMMap ret = NULL;
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LUMIERA_MUTEX_SECTION (mmapings, &self->lock)
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{
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REQUIRE (llist_is_empty (acquirer));
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/* find best matching mmap, crude way */
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LLIST_FOREACH (&self->mmaps, node)
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{
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LumieraMMap mmap = LLIST_TO_STRUCTP (node, lumiera_mmap, searchnode);
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if (mmap->size >= size && mmap->start <= start && mmap->start+mmap->size >= start+size)
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{
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ret = mmap;
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break;
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}
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}
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if (!ret)
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{
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/* create new mmap */
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TRACE (mmapings, "mmap not found, creating", mmap);
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ret = lumiera_mmap_new (file, acquirer, start, size, self->chunksize);
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llist_insert_head (&self->mmaps, &ret->searchnode);
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TODO ("sort search list");
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}
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else
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{
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/* found mmap */
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UNIMPLEMENTED ("reuse existing mmap");
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//lumiera_mmapcache_checkout (lumiera_mcache, self);
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// checkout add acquirer
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}
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}
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return ret;
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}
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void
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lumiera_mmapings_release_mmap (LumieraMMapings self, LList acquirer, LumieraMMap map)
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{
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TRACE (mmapings);
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LUMIERA_MUTEX_SECTION (mmapings, &self->lock)
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{
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llist_unlink (acquirer);
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if (llist_is_empty (&map->cachenode))
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{
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TRACE (mmapings, "checkin");
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lumiera_mmapcache_checkin (lumiera_mcache, map);
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}
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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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