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| author | Robin Murphy <robin.murphy@arm.com> | 2022-03-03 17:40:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:22:48 +0300 |
| commit | 8a4521456b5497a430ed026f31a2bd1e347c0747 (patch) | |
| tree | 739b5681f07375204b587b4fa7e83d6de55cea9f /drivers/iommu | |
| parent | fe953e0f77e55d004a5b0c533262e389d01e3198 (diff) | |
| download | linux-8a4521456b5497a430ed026f31a2bd1e347c0747.tar.xz | |
iommu/iova: Improve 32-bit free space estimate
commit 5b61343b50590fb04a3f6be2cdc4868091757262 upstream.
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>
Cc: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/iova.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 920fcc27c9a1..cae5a73ff518 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -154,10 +154,11 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) cached_iova = to_iova(iovad->cached32_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 = to_iova(iovad->cached_node); if (free->pfn_lo >= cached_iova->pfn_lo) |