xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

FROMGIT: iommu/iova: Improve 32-bit free space estimate

Browse Source 
For various reasons based on the allocator behaviour and typical
use-cases at the time, when the max32_alloc_size optimisation was
introduced it seemed reasonable to couple the reset of the tracked
size to the update of cached32_node upon freeing a relevant IOVA.
However, since subsequent optimisations focused on helping genuine
32-bit devices make best use of even more limited address spaces, it
is now a lot more likely for cached32_node to be anywhere in a "full"
32-bit address space, and as such more likely for space to become
available from IOVAs below that node being freed.

At this point, the short-cut in __cached_rbnode_delete_update() really
doesn't hold up any more, and we need to fix the logic to reliably
provide the expected behaviour. We still want cached32_node to only move
upwards, but we should reset the allocation size if *any* 32-bit space
has become available.

Reported-by: Yunfei Wang <yf.wang@mediatek.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
Link: https://lore.kernel.org/r/033815732d83ca73b13c11485ac39336f15c3b40.1646318408.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Bug: 223712131
(cherry picked from commit 5b61343b50590fb04a3f6be2cdc4868091757262
 https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git core)
Signed-off-by: Yunfei Wang <yf.wang@mediatek.com>
Change-Id: I5026411dd022c6ddea5c0e4da6e69c7b14162c3f
This commit is contained in:
Yunfei Wang
2022-03-10 14:36:48 +08:00
committed by Suren Baghdasaryan
parent d9845e9e5c
commit ec48b1892e
1 changed files with 3 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/iommu/iova.c
View File

@@ -139,10 +139,11 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
if (free == cached_iova ||
(free->pfn_hi < iovad->dma_32bit_pfn &&
free->pfn_lo >= cached_iova->pfn_lo)) {
free->pfn_lo >= cached_iova->pfn_lo))
iovad->cached32_node = rb_next(&free->node);
if (free->pfn_lo < iovad->dma_32bit_pfn)
iovad->max32_alloc_size = iovad->dma_32bit_pfn;
}
cached_iova = rb_entry(iovad->cached_node, struct iova, node);
if (free->pfn_lo >= cached_iova->pfn_lo)