Messages in this thread | | | Date | Thu, 28 Sep 2017 15:41:16 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v2] iommu/iova: Try harder to allocate from rcache magazine |
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On Thu, Sep 28, 2017 at 11:31:23AM +0100, Robin Murphy wrote: > When devices with different DMA masks are using the same domain, or for > PCI devices where we usually try a speculative 32-bit allocation first, > there is a fair possibility that the top PFN of the rcache stack at any > given time may be unsuitable for the lower limit, prompting a fallback > to allocating anew from the rbtree. Consequently, we may end up > artifically increasing pressure on the 32-bit IOVA space as unused IOVAs > accumulate lower down in the rcache stacks, while callers with 32-bit > masks also impose unnecessary rbtree overhead. > > In such cases, let's try a bit harder to satisfy the allocation locally > first - scanning the whole stack should still be relatively inexpensive. > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > > v2: There's no need for a 'proper' stack rotation > > drivers/iommu/iova.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-)
Thanks, applied the series.
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