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@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_device.c | 14 ++--
drivers/gpu/drm/ttm/ttm_tt.c | 112 ++++++++++++-------------------
include/drm/ttm/ttm_tt.h | 3 +-
3 files changed, 53 insertions(+), 76 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 95e1b7b1f2e6..388da2a7f0bb 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -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;
unsigned i;
@@ -79,8 +78,15 @@ 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);
spin_lock_init(&glob->lru_lock);
glob->dummy_read_page = alloc_page(__GFP_ZERO | GFP_DMA32);
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 2f0833c98d2c..5d8820725b75 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -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_bo_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);
- 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_bo_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
+ atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
+ if (bdev->pool.use_dma32)
+ atomic_long_sub(ttm->num_pages, &ttm_dma32_pages_allocated);
-/* 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;
+ ttm->page_flags &= ~TTM_PAGE_FLAG_PRIV_POPULATED;
}
-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
-
- 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);
-}
+ if (!ttm_pages_limit)
+ ttm_pages_limit = num_pages;
-/**
- * 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;
}
diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h
index 069f8130241a..134d09ef7766 100644
--- a/include/drm/ttm/ttm_tt.h
+++ b/include/drm/ttm/ttm_tt.h
@@ -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>
--
2.25.1
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