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drm/ttm: switch back to static allocation limits for now

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The shrinker based approach still has some flaws. Especially that we need
temporary pages to free up the pages allocated to the driver is problematic
in a shrinker.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324134845.2338-1-christian.koenig@amd.com
This commit is contained in:
Christian König 2021-03-24 13:50:56 +01:00
parent e55f2ffc4d
commit 680dcede27
3 changed files with 54 additions and 77 deletions
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14
drivers/gpu/drm/ttm/ttm_device.c
View file

@ -53,7 +53,6 @@ static void ttm_global_release(void)
goto out;
ttm_pool_mgr_fini();
ttm_tt_mgr_fini();
__free_page(glob->dummy_read_page);
memset(glob, 0, sizeof(*glob));
@ -64,7 +63,7 @@ static void ttm_global_release(void)
static int ttm_global_init(void)
{
struct ttm_global *glob = &ttm_glob;
unsigned long num_pages;
unsigned long num_pages, num_dma32;
struct sysinfo si;
int ret = 0;
@ -78,8 +77,15 @@ static int ttm_global_init(void)
* system memory.
*/
num_pages = ((u64)si.totalram * si.mem_unit) >> PAGE_SHIFT;
ttm_pool_mgr_init(num_pages * 50 / 100);
ttm_tt_mgr_init();
num_pages /= 2;
/* But for DMA32 we limit ourself to only use 2GiB maximum. */
num_dma32 = (u64)(si.totalram - si.totalhigh) * si.mem_unit
>> PAGE_SHIFT;
num_dma32 = min(num_dma32, 2UL << (30 - PAGE_SHIFT));
ttm_pool_mgr_init(num_pages);
ttm_tt_mgr_init(num_pages, num_dma32);
glob->dummy_read_page = alloc_page(__GFP_ZERO | GFP_DMA32);

114
drivers/gpu/drm/ttm/ttm_tt.c
View file

@ -40,8 +40,18 @@
#include "ttm_module.h"
static struct shrinker mm_shrinker;
static atomic_long_t swapable_pages;
static unsigned long ttm_pages_limit;
MODULE_PARM_DESC(pages_limit, "Limit for the allocated pages");
module_param_named(pages_limit, ttm_pages_limit, ulong, 0644);
static unsigned long ttm_dma32_pages_limit;
MODULE_PARM_DESC(dma32_pages_limit, "Limit for the allocated DMA32 pages");
module_param_named(dma32_pages_limit, ttm_dma32_pages_limit, ulong, 0644);
static atomic_long_t ttm_pages_allocated;
static atomic_long_t ttm_dma32_pages_allocated;
/*
* Allocates a ttm structure for the given BO.
@ -294,8 +304,6 @@ static void ttm_tt_add_mapping(struct ttm_device *bdev, struct ttm_tt *ttm)
for (i = 0; i < ttm->num_pages; ++i)
ttm->pages[i]->mapping = bdev->dev_mapping;
atomic_long_add(ttm->num_pages, &swapable_pages);
}
int ttm_tt_populate(struct ttm_device *bdev,
@ -309,12 +317,25 @@ int ttm_tt_populate(struct ttm_device *bdev,
if (ttm_tt_is_populated(ttm))
return 0;
atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
if (bdev->pool.use_dma32)
atomic_long_add(ttm->num_pages, &ttm_dma32_pages_allocated);
while (atomic_long_read(&ttm_pages_allocated) > ttm_pages_limit ||
atomic_long_read(&ttm_dma32_pages_allocated) >
ttm_dma32_pages_limit) {
ret = ttm_global_swapout(ctx, GFP_KERNEL);
if (ret)
goto error;
}
if (bdev->funcs->ttm_tt_populate)
ret = bdev->funcs->ttm_tt_populate(bdev, ttm, ctx);
else
ret = ttm_pool_alloc(&bdev->pool, ttm, ctx);
if (ret)
return ret;
goto error;
ttm_tt_add_mapping(bdev, ttm);
ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED;
@ -327,6 +348,12 @@ int ttm_tt_populate(struct ttm_device *bdev,
}
return 0;
error:
atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
if (bdev->pool.use_dma32)
atomic_long_sub(ttm->num_pages, &ttm_dma32_pages_allocated);
return ret;
}
EXPORT_SYMBOL(ttm_tt_populate);
@ -342,12 +369,9 @@ static void ttm_tt_clear_mapping(struct ttm_tt *ttm)
(*page)->mapping = NULL;
(*page++)->index = 0;
}
atomic_long_sub(ttm->num_pages, &swapable_pages);
}
void ttm_tt_unpopulate(struct ttm_device *bdev,
struct ttm_tt *ttm)
void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
{
if (!ttm_tt_is_populated(ttm))
return;
@ -357,76 +381,24 @@ void ttm_tt_unpopulate(struct ttm_device *bdev,
bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
else
ttm_pool_free(&bdev->pool, ttm);
atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
if (bdev->pool.use_dma32)
atomic_long_sub(ttm->num_pages, &ttm_dma32_pages_allocated);
ttm->page_flags &= ~TTM_PAGE_FLAG_PRIV_POPULATED;
}
/* As long as pages are available make sure to release at least one */
static unsigned long ttm_tt_shrinker_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
struct ttm_operation_ctx ctx = {
.no_wait_gpu = false
};
int ret;
ret = ttm_global_swapout(&ctx, GFP_NOFS);
return ret < 0 ? SHRINK_EMPTY : ret;
}
/* Return the number of pages available or SHRINK_EMPTY if we have none */
static unsigned long ttm_tt_shrinker_count(struct shrinker *shrink,
struct shrink_control *sc)
{
unsigned long num_pages;
num_pages = atomic_long_read(&swapable_pages);
return num_pages ? num_pages : SHRINK_EMPTY;
}
#ifdef CONFIG_DEBUG_FS
/* Test the shrinker functions and dump the result */
static int ttm_tt_debugfs_shrink_show(struct seq_file *m, void *data)
{
struct shrink_control sc = { .gfp_mask = GFP_KERNEL };
fs_reclaim_acquire(GFP_KERNEL);
seq_printf(m, "%lu/%lu\n", ttm_tt_shrinker_count(&mm_shrinker, &sc),
ttm_tt_shrinker_scan(&mm_shrinker, &sc));
fs_reclaim_release(GFP_KERNEL);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ttm_tt_debugfs_shrink);
#endif
/**
* ttm_tt_mgr_init - register with the MM shrinker
*
* Register with the MM shrinker for swapping out BOs.
*/
int ttm_tt_mgr_init(void)
void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages)
{
#ifdef CONFIG_DEBUG_FS
debugfs_create_file("tt_shrink", 0400, ttm_debugfs_root, NULL,
&ttm_tt_debugfs_shrink_fops);
#endif
if (!ttm_pages_limit)
ttm_pages_limit = num_pages;
mm_shrinker.count_objects = ttm_tt_shrinker_count;
mm_shrinker.scan_objects = ttm_tt_shrinker_scan;
mm_shrinker.seeks = 1;
return register_shrinker(&mm_shrinker);
}
/**
* ttm_tt_mgr_fini - unregister our MM shrinker
*
* Unregisters the MM shrinker.
*/
void ttm_tt_mgr_fini(void)
{
unregister_shrinker(&mm_shrinker);
if (!ttm_dma32_pages_limit)
ttm_dma32_pages_limit = num_dma32_pages;
}

3
include/drm/ttm/ttm_tt.h
View file

@ -157,8 +157,7 @@ int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_oper
*/
void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm);
int ttm_tt_mgr_init(void);
void ttm_tt_mgr_fini(void);
void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
#if IS_ENABLED(CONFIG_AGP)
#include <linux/agp_backend.h>