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| author | Alex Williamson <alex.williamson@redhat.com> | 2017-04-18 01:07:06 +0300 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2017-04-19 00:01:15 +0300 |
| commit | 7cb671e7a34d73b29df77d0b53492277744e57e7 (patch) | |
| tree | c8ec48571db212aabe91b5fc77a20fb8277d78a0 /drivers/vfio | |
| parent | 80dbe1fbafbf469fd19862f0d400b769bff0ee46 (diff) | |
| download | linux-7cb671e7a34d73b29df77d0b53492277744e57e7.tar.xz | |
vfio/type1: Reduce repetitive calls in vfio_pin_pages_remote()
vfio_pin_pages_remote() is typically called to iterate over a range
of memory. Testing CAP_IPC_LOCK is relatively expensive, so it makes
sense to push it up to the caller, which can then repeatedly call
vfio_pin_pages_remote() using that value. This can show nearly a 20%
improvement on the worst case path through VFIO_IOMMU_MAP_DMA with
contiguous page mapping disabled. Testing RLIMIT_MEMLOCK is much more
lightweight, but we bring it along on the same principle and it does
seem to show a marginal improvement.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
| -rw-r--r-- | drivers/vfio/vfio_iommu_type1.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 372e4f626138..8549cb111627 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -380,10 +380,10 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, * first page and all consecutive pages with the same locking. */ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, - long npage, unsigned long *pfn_base) + long npage, unsigned long *pfn_base, + bool lock_cap, unsigned long limit) { - unsigned long pfn = 0, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; - bool lock_cap = capable(CAP_IPC_LOCK); + unsigned long pfn = 0; long ret, pinned = 0, lock_acct = 0; bool rsvd; dma_addr_t iova = vaddr - dma->vaddr + dma->iova; @@ -924,13 +924,15 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma, unsigned long vaddr = dma->vaddr; size_t size = map_size; long npage; - unsigned long pfn; + unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + bool lock_cap = capable(CAP_IPC_LOCK); int ret = 0; while (size) { /* Pin a contiguous chunk of memory */ npage = vfio_pin_pages_remote(dma, vaddr + dma->size, - size >> PAGE_SHIFT, &pfn); + size >> PAGE_SHIFT, &pfn, + lock_cap, limit); if (npage <= 0) { WARN_ON(!npage); ret = (int)npage; @@ -1040,6 +1042,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, { struct vfio_domain *d; struct rb_node *n; + unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + bool lock_cap = capable(CAP_IPC_LOCK); int ret; /* Arbitrarily pick the first domain in the list for lookups */ @@ -1086,7 +1090,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, npage = vfio_pin_pages_remote(dma, vaddr, n >> PAGE_SHIFT, - &pfn); + &pfn, lock_cap, + limit); if (npage <= 0) { WARN_ON(!npage); ret = (int)npage; |