From: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
To: joro@8bytes.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, robin.murphy@arm.com
Cc: tomasz.nowicki@cavium.com, jnair@caviumnetworks.com,
Robert.Richter@cavium.com, Vadim.Lomovtsev@cavium.com,
Jan.Glauber@cavium.com, gklkml16@gmail.com
Subject: [PATCH] iommu/iova: Optimise attempts to allocate iova from 32bit address range
Date: Tue, 7 Aug 2018 14:24:37 +0530 [thread overview]
Message-ID: <20180807085437.15965-1-ganapatrao.kulkarni@cavium.com> (raw)
As an optimisation for PCI devices, there is always first attempt
been made to allocate iova from SAC address range. This will lead
to unnecessary attempts/function calls, when there are no free ranges
available.
This patch optimises by adding flag to track previous failed attempts
and avoids further attempts until replenish happens.
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
---
This patch is based on comments from Robin Murphy <robin.murphy@arm.com>
for patch [1]
[1] https://lkml.org/lkml/2018/4/19/780
drivers/iommu/iova.c | 11 ++++++++++-
include/linux/iova.h | 1 +
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 83fe262..d97bb5a 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -56,6 +56,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
iovad->granule = granule;
iovad->start_pfn = start_pfn;
iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad));
+ iovad->free_32bit_pfns = true;
iovad->flush_cb = NULL;
iovad->fq = NULL;
iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
@@ -139,8 +140,10 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
if (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);
+ iovad->free_32bit_pfns = true;
+ }
cached_iova = rb_entry(iovad->cached_node, struct iova, node);
if (free->pfn_lo >= cached_iova->pfn_lo)
@@ -290,6 +293,10 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
struct iova *new_iova;
int ret;
+ if (limit_pfn <= iovad->dma_32bit_pfn &&
+ !iovad->free_32bit_pfns)
+ return NULL;
+
new_iova = alloc_iova_mem();
if (!new_iova)
return NULL;
@@ -299,6 +306,8 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
if (ret) {
free_iova_mem(new_iova);
+ if (limit_pfn <= iovad->dma_32bit_pfn)
+ iovad->free_32bit_pfns = false;
return NULL;
}
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 928442d..3810ba9 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -96,6 +96,7 @@ struct iova_domain {
flush-queues */
atomic_t fq_timer_on; /* 1 when timer is active, 0
when not */
+ bool free_32bit_pfns;
};
static inline unsigned long iova_size(struct iova *iova)
--
2.9.4
next reply other threads:[~2018-08-07 8:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 8:54 Ganapatrao Kulkarni [this message]
2018-08-09 16:24 ` [PATCH] iommu/iova: Optimise attempts to allocate iova from 32bit address range Robin Murphy
2018-08-09 17:49 ` Ganapatrao Kulkarni
2018-08-09 20:43 ` Robin Murphy
2018-08-10 9:24 ` Ganapatrao Kulkarni
2018-08-10 9:49 ` Robin Murphy
2018-08-10 10:01 ` Ganapatrao Kulkarni
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