Messages in this thread | | | Date | Tue, 20 Dec 2016 10:22:09 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] iommu/arm-smmu-v3: avoid over allocating for l2 stream tables |
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Hi Nate,
On Mon, Dec 19, 2016 at 03:26:40PM -0500, Nate Watterson wrote: > Currently, all l2 stream tables are being allocated with space for > (1<<split) stes without regard to the number of sid bits the smmu > physically supports. To avoid allocating memory for inaccessible > stes, this patch limits the span of an l2 table to be no larger > than the sid size of the smmu to which it belongs. > > Signed-off-by: Nate Watterson <nwatters@codeaurora.org> > --- > drivers/iommu/arm-smmu-v3.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-)
I can't help but think you'd be better off using a linear stream table in this scenario. If we hack the feature check for ARM_SMMU_FEAT_2_LVL_STRTAB so that it doesn't report support for 2 level tables if the number of sids is less than that covered by a single l2 entry, would that solve your problem?
Will
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