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Commit 81ee53cc authored by Mitchel Humpherys's avatar Mitchel Humpherys Committed by Matt Wagantall
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iommu: io-pgtable-arm: Flush all tlbs at end of unmap 



Rather than calling the tlb maintenance routines throughout the course
of the unmap operation, just flush the entire tlb for the context in
question all at once, at the very end of the unmap.  This greatly
improves performance for large page tables (which is common for large
buffers in a heavily fragmented system).

In my testing, this optimization gave a ~10% speedup when unmapping 64K.

Change-Id: Iaa2b211e730dad6bd9235ef98dd2a89cf541e663
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
parent be2913f5

drivers/iommu/io-pgtable-arm.c

+1 −7
Original line number Diff line number Diff line
@@ -452,8 +452,6 @@ static int arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data, 


	*ptep = table;

	tlb->flush_pgtable(ptep, sizeof(*ptep), cookie);

	iova &= ~(blk_size - 1);

	tlb->tlb_add_flush(iova, blk_size, true, cookie);

	return size;

}
@@ -480,12 +478,8 @@ static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, 


		if (!iopte_leaf(pte, lvl)) {

			/* Also flush any partial walks */

			tlb->tlb_add_flush(iova, size, false, cookie);

			tlb->tlb_sync(data->iop.cookie);

			ptep = iopte_deref(pte, data);

			__arm_lpae_free_pgtable(data, lvl + 1, ptep);

		} else {

			tlb->tlb_add_flush(iova, size, true, cookie);

		}



		return size;
@@ -515,7 +509,7 @@ static int arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova, 


	unmapped = __arm_lpae_unmap(data, iova, size, lvl, ptep);

	if (unmapped)

		iop->cfg.tlb->tlb_sync(iop->cookie);

		iop->cfg.tlb->tlb_flush_all(iop->cookie);



	return unmapped;

}