Re: [PATCH 8/9] drm/ttm: Don't count pages in SG BOs against pages_limit

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Am 14.04.21 um 11:15 schrieb Daniel Vetter:
On Wed, Apr 14, 2021 at 08:51:51AM +0200, Christian König wrote:
Am 14.04.21 um 08:48 schrieb Felix Kuehling:
Pages in SG BOs were not allocated by TTM. So don't count them against
TTM's pages limit.

Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Reviewed-by: Christian König <christian.koenig@xxxxxxx>

Going to pick that one up for inclusion in drm-misc-next.
See my other email, but why do we need this? A bit more explanation is imo
needed here at least, since we still need to guarantee that allocations
don't over the limit in total for all gpu buffers together. At least until
the shrinker has landed.

And this here just opens up the barn door without any explanation why it's
ok.

The SG based BOs might not even be backed by pages. E.g. exported VRAM.

So either they are exported by a driver which should have accounted for the allocation, exported by TTM which already did the accounting or doesn't even point to pages at all.

This is really a bug fix to recreate the behavior we had before moving the accounting to this place.

Christian.

-Daniel

Regards,
Christian.

---
   drivers/gpu/drm/ttm/ttm_tt.c | 27 ++++++++++++++++++---------
   1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 5d8820725b75..e8b8c3257392 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -317,9 +317,12 @@ 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);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		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) >
@@ -350,9 +353,12 @@ 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);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		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);
@@ -382,9 +388,12 @@ void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *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);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		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;
   }
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&amp;data=04%7C01%7Cchristian.koenig%40amd.com%7C3075d7fd16644322a13608d8ff25d59b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637539885255795187%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=KOnHA1CbNFjjMZR2rgHmGkH%2B7C84YCtA6u9V1wBAay4%3D&amp;reserved=0

_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/amd-gfx




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux