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author | Joerg Roedel <jroedel@suse.de> | 2017-08-10 16:14:59 +0200 |
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committer | Joerg Roedel <jroedel@suse.de> | 2017-08-15 18:23:51 +0200 |
commit | fb418dab8a4f01dde0c025d15145c589ec02796b (patch) | |
tree | a3248e1152ca546661147605d2480528a8775af6 /include/linux/iova.h | |
parent | 1928210107edd4fa786199fef6b875d3af3bef88 (diff) | |
download | linux-stable-fb418dab8a4f01dde0c025d15145c589ec02796b.tar.gz linux-stable-fb418dab8a4f01dde0c025d15145c589ec02796b.tar.bz2 linux-stable-fb418dab8a4f01dde0c025d15145c589ec02796b.zip |
iommu/iova: Add flush counters to Flush-Queue implementation
There are two counters:
* fq_flush_start_cnt - Increased when a TLB flush
is started.
* fq_flush_finish_cnt - Increased when a TLB flush
is finished.
The fq_flush_start_cnt is assigned to every Flush-Queue
entry on its creation. When freeing entries from the
Flush-Queue, the value in the entry is compared to the
fq_flush_finish_cnt. The entry can only be freed when its
value is less than the value of fq_flush_finish_cnt.
The reason for these counters it to take advantage of IOMMU
TLB flushes that happened on other CPUs. These already
flushed the TLB for Flush-Queue entries on other CPUs so
that they can already be freed without flushing the TLB
again.
This makes it less likely that the Flush-Queue is full and
saves IOMMU TLB flushes.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include/linux/iova.h')
-rw-r--r-- | include/linux/iova.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/iova.h b/include/linux/iova.h index 1ae85248ec50..985b8008999e 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -14,6 +14,7 @@ #include <linux/types.h> #include <linux/kernel.h> #include <linux/rbtree.h> +#include <linux/atomic.h> #include <linux/dma-mapping.h> /* iova structure */ @@ -52,6 +53,7 @@ struct iova_fq_entry { unsigned long iova_pfn; unsigned long pages; unsigned long data; + u64 counter; /* Flush counter when this entrie was added */ }; /* Per-CPU Flush Queue structure */ @@ -77,6 +79,12 @@ struct iova_domain { iova entry */ struct iova_fq __percpu *fq; /* Flush Queue */ + + atomic64_t fq_flush_start_cnt; /* Number of TLB flushes that + have been started */ + + atomic64_t fq_flush_finish_cnt; /* Number of TLB flushes that + have been finished */ }; static inline unsigned long iova_size(struct iova *iova) |