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/*
* \brief Memory subsystem
* \author Thomas Friebel <tf13@os.inf.tu-dresden.de>
* \author Christian Helmuth <ch12@os.inf.tu-dresden.de>
* \date 2006-11-03
*
* The memory subsystem provides the backing store for DMA-able memory via
* large malloc and slabs.
*
* FIXME check thread-safety and add locks where appropriate
*/
#include "ddekit/memory.h"
extern void * linux_kmalloc (unsigned int size, int priority);
/****************
** Page cache **
****************/
/* FIXME revisit two-linked-lists approach - we could get rid of the
* pcache_free lists, because these descriptors can also be allocated
* whenever the need arises. (XXX: Check how this hurts performance.)
*/
/*****************************************************************************
DDEKit maintains a list of free pages that can be used for growing
existing DDEKit slabs. We distinguish between 2 types of pages: the ones
that have been allocated from physically contiguous dataspaces and the the
ones that have not.
For each type of cache, we maintain two lists: a list of free pages that
can be used to grow a cache (pcache_used) and a list of free pcache entries
that can be used to store pages when they get freed (pcache_free). The
reason for this is that by using these two lists, cache operations can be
done atomically using cmpxchg.
The function ddekit_slab_setup_page_cache() is used to tune the number of
cached pages.
******************************************************************************/
/* page cache to minimize allocations from external servers */
struct ddekit_pcache
{
struct ddekit_pcache *next;
void *page;
int contig;
};
/**
* Setup page cache for all slabs
*
* \param pages maximal number of memory pages
*
* If the maximal number of unused pages is exceeded, subsequent deallocation
* will be freed at the memory server. This page cache caches pages from all
* slabs.
*/
void ddekit_slab_setup_page_cache(unsigned pages)
{
}
/*******************************
** Slab cache implementation **
*******************************/
/* ddekit slab facilitates l4slabs */
struct ddekit_slab
{
int size;
int contiguous;
};
/**
* Allocate object in slab
*/
void *ddekit_slab_alloc(struct ddekit_slab * slab)
{
return linux_kmalloc (slab->size, 0);
}
/**
* Free object in slab
*/
void ddekit_slab_free(struct ddekit_slab * slab, void *objp)
{
linux_kfree (objp);
}
/**
* Store user pointer in slab cache
*/
void ddekit_slab_set_data(struct ddekit_slab * slab, void *data)
{
#if 0
l4slab_set_data(&slab->cache, data);
#endif
}
/**
* Read user pointer from slab cache
*/
void *ddekit_slab_get_data(struct ddekit_slab * slab)
{
#if 0
return l4slab_get_data(&slab->cache);
#endif
}
/**
* Destroy slab cache
*
* \param slab pointer to slab cache structure
*/
void ddekit_slab_destroy (struct ddekit_slab * slab)
{
ddekit_simple_free(slab);
}
/**
* Initialize slab cache
*
* \param size size of cache objects
* \param contiguous make this slab use physically contiguous memory
*
* \return pointer to new slab cache or 0 on error
*/
struct ddekit_slab * ddekit_slab_init(unsigned size, int contiguous)
{
struct ddekit_slab * slab;
slab = (struct ddekit_slab *) ddekit_simple_malloc(sizeof(*slab));
slab->size = size;
slab->contiguous = contiguous;
return slab;
}
/**********************************
** Large block memory allocator **
**********************************/
/**
* Free large block of memory
*
* This is no useful for allocation < page size.
*/
void ddekit_large_free(void *objp)
{
return linux_kfree (objp);
}
/**
* Allocate large block of memory
*
* This is no useful for allocation < page size.
*/
void *ddekit_large_malloc(int size)
{
// TODO I hope linux_kmalloc can provide large enough pages.
return linux_kmalloc (size, 0);
}
/**
* Allocate large block of memory (special interface)
*
* This is no useful for allocation < page size.
*
* FIXME implementation missing...
*/
void *ddekit_contig_malloc(unsigned long size,
unsigned long low, unsigned long high,
unsigned long alignment, unsigned long boundary)
{
#if 0
void *res;
int err;
int pages;
l4_size_t tmp;
l4dm_mem_addr_t dm_paddr;
size = l4_round_page(size);
pages = size >> L4_PAGESHIFT;
res = l4dm_mem_allocate_named(size, L4DM_CONTIGUOUS | L4DM_PINNED | L4RM_MAP | L4RM_LOG2_ALIGNED);
if (res) {
/* check if res meets low/high/alignment/boundary
* and panic if it is not the case
* XXXY
*/
/* get physical address */
err = l4dm_mem_phys_addr(res, 1, &dm_paddr, 1, &tmp);
if (err != 1)
ddekit_debug("contigmalloc: error getting physical address of new page!\n");
/* set PTE */
ddekit_set_ptes(res, dm_paddr.addr, pages, PTE_TYPE_CONTIG);
}
return res;
#else
ddekit_debug("%s: not implemented\n", __func__);
return 0;
#endif
}
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