alistair23-linux/drivers/gpu/drm/drm_cache.c
Chris Wilson 9da3da660d drm/i915: Replace the array of pages with a scatterlist
Rather than have multiple data structures for describing our page layout
in conjunction with the array of pages, we can migrate all users over to
a scatterlist.

One major advantage, other than unifying the page tracking structures,
this offers is that we replace the vmalloc'ed array (which can be up to
a megabyte in size) with a chain of individual pages which helps reduce
memory pressure.

The disadvantage is that we then do not have a simple array to iterate,
or to access randomly. The common case for this is in the relocation
processing, which will typically fit within a single scatterlist page
and so be almost the same cost as the simple array. For iterating over
the array, the extra function call could be optimised away, but in
reality is an insignificant cost of either binding the pages, or
performing the pwrite/pread.

v2: Fix drm_clflush_sg() to not invoke wbinvd as well! And fix the
trivial compile error from rebasing.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-09-20 14:22:57 +02:00

150 lines
3.8 KiB
C

/**************************************************************************
*
* Copyright (c) 2006-2007 Tungsten Graphics, Inc., Cedar Park, TX., USA
* All Rights Reserved.
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*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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/*
* Authors: Thomas Hellström <thomas-at-tungstengraphics-dot-com>
*/
#include <linux/export.h>
#include "drmP.h"
#if defined(CONFIG_X86)
static void
drm_clflush_page(struct page *page)
{
uint8_t *page_virtual;
unsigned int i;
const int size = boot_cpu_data.x86_clflush_size;
if (unlikely(page == NULL))
return;
page_virtual = kmap_atomic(page);
for (i = 0; i < PAGE_SIZE; i += size)
clflush(page_virtual + i);
kunmap_atomic(page_virtual);
}
static void drm_cache_flush_clflush(struct page *pages[],
unsigned long num_pages)
{
unsigned long i;
mb();
for (i = 0; i < num_pages; i++)
drm_clflush_page(*pages++);
mb();
}
static void
drm_clflush_ipi_handler(void *null)
{
wbinvd();
}
#endif
void
drm_clflush_pages(struct page *pages[], unsigned long num_pages)
{
#if defined(CONFIG_X86)
if (cpu_has_clflush) {
drm_cache_flush_clflush(pages, num_pages);
return;
}
if (on_each_cpu(drm_clflush_ipi_handler, NULL, 1) != 0)
printk(KERN_ERR "Timed out waiting for cache flush.\n");
#elif defined(__powerpc__)
unsigned long i;
for (i = 0; i < num_pages; i++) {
struct page *page = pages[i];
void *page_virtual;
if (unlikely(page == NULL))
continue;
page_virtual = kmap_atomic(page);
flush_dcache_range((unsigned long)page_virtual,
(unsigned long)page_virtual + PAGE_SIZE);
kunmap_atomic(page_virtual);
}
#else
printk(KERN_ERR "Architecture has no drm_cache.c support\n");
WARN_ON_ONCE(1);
#endif
}
EXPORT_SYMBOL(drm_clflush_pages);
void
drm_clflush_sg(struct sg_table *st)
{
#if defined(CONFIG_X86)
if (cpu_has_clflush) {
struct scatterlist *sg;
int i;
mb();
for_each_sg(st->sgl, sg, st->nents, i)
drm_clflush_page(sg_page(sg));
mb();
return;
}
if (on_each_cpu(drm_clflush_ipi_handler, NULL, 1) != 0)
printk(KERN_ERR "Timed out waiting for cache flush.\n");
#else
printk(KERN_ERR "Architecture has no drm_cache.c support\n");
WARN_ON_ONCE(1);
#endif
}
EXPORT_SYMBOL(drm_clflush_sg);
void
drm_clflush_virt_range(char *addr, unsigned long length)
{
#if defined(CONFIG_X86)
if (cpu_has_clflush) {
char *end = addr + length;
mb();
for (; addr < end; addr += boot_cpu_data.x86_clflush_size)
clflush(addr);
clflush(end - 1);
mb();
return;
}
if (on_each_cpu(drm_clflush_ipi_handler, NULL, 1) != 0)
printk(KERN_ERR "Timed out waiting for cache flush.\n");
#else
printk(KERN_ERR "Architecture has no drm_cache.c support\n");
WARN_ON_ONCE(1);
#endif
}
EXPORT_SYMBOL(drm_clflush_virt_range);