| Message ID | 1542721320-233109-1-git-send-email-john.garry@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] iommu/dma: Use NUMA aware memory allocations in __iommu_dma_alloc_pages() | expand |
On 20/11/2018 13:42, John Garry wrote: > From: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> > > Change function __iommu_dma_alloc_pages() to allocate memory/pages > for DMA from respective device NUMA node. > > Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> > [JPG: Modifed to use kvzalloc() and fixed indentation] > Signed-off-by: John Garry <john.garry@huawei.com> > --- > Difference v1->v2: > - Add Ganapatrao's tag and change author > > This patch was originally posted by Ganapatrao in [1]. > > However, after initial review, it was never reposted (due to lack of > cycles, I think). In addition, the functionality in its sibling patches > were merged through patches, as mentioned in [2]; this also refers to a > discussion on device local allocations vs CPU local allocations for DMA > pool, and which is better [3]. > > However, as mentioned in [3], dma_alloc_coherent() uses the locality > information from the device - as in direct DMA - so this patch is just > applying this same policy. > > [1] https://lore.kernel.org/patchwork/patch/833004/ > [2] https://lkml.org/lkml/2018/8/22/391 > [3] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1692998.html > > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index d1b0475..ada00bc 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -449,20 +449,17 @@ static void __iommu_dma_free_pages(struct page **pages, int count) > kvfree(pages); > } > > -static struct page **__iommu_dma_alloc_pages(unsigned int count, > - unsigned long order_mask, gfp_t gfp) > +static struct page **__iommu_dma_alloc_pages(struct device *dev, > + unsigned int count, unsigned long order_mask, gfp_t gfp) > { > struct page **pages; > - unsigned int i = 0, array_size = count * sizeof(*pages); > + unsigned int i = 0, nid = dev_to_node(dev); > > order_mask &= (2U << MAX_ORDER) - 1; > if (!order_mask) > return NULL; > > - if (array_size <= PAGE_SIZE) > - pages = kzalloc(array_size, GFP_KERNEL); > - else > - pages = vzalloc(array_size); > + pages = kvzalloc_node(count * sizeof(*pages), GFP_KERNEL, nid); The pages array is only accessed by the CPU servicing the iommu_dma_alloc() call, and is usually freed again before that call even returns. It's certainly never touched by the device, so forcing it to a potentially non-local node doesn't make a great deal of sense. > if (!pages) > return NULL; > > @@ -483,8 +480,10 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, > unsigned int order = __fls(order_mask); > > order_size = 1U << order; > - page = alloc_pages((order_mask - order_size) ? > - gfp | __GFP_NORETRY : gfp, order); > + page = alloc_pages_node(nid, > + (order_mask - order_size) ? > + gfp | __GFP_NORETRY : gfp, > + order); If we're touching this, can we sort out that horrendous ternary? FWIW I found I have a local version of the original patch which I tweaked at the time, and apparently I reworked this hunk as below, which does seem somewhat nicer for the same diffstat. Robin. @@ -446,10 +443,12 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, for (order_mask &= (2U << __fls(count)) - 1; order_mask; order_mask &= ~order_size) { unsigned int order = __fls(order_mask); + gfp_t alloc_flags = gfp; order_size = 1U << order; - page = alloc_pages((order_mask - order_size) ? - gfp | __GFP_NORETRY : gfp, order); + if (order_size < order_mask) + alloc_flags |= __GFP_NORETRY; + page = alloc_pages_node(nid, alloc_flags, order); if (!page) continue; if (!order)
On 20/11/2018 14:20, Robin Murphy wrote: > On 20/11/2018 13:42, John Garry wrote: >> From: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> >> >> Change function __iommu_dma_alloc_pages() to allocate memory/pages >> for DMA from respective device NUMA node. >> >> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> >> [JPG: Modifed to use kvzalloc() and fixed indentation] >> Signed-off-by: John Garry <john.garry@huawei.com> >> --- >> Difference v1->v2: >> - Add Ganapatrao's tag and change author >> >> This patch was originally posted by Ganapatrao in [1]. >> >> However, after initial review, it was never reposted (due to lack of >> cycles, I think). In addition, the functionality in its sibling patches >> were merged through patches, as mentioned in [2]; this also refers to a >> discussion on device local allocations vs CPU local allocations for DMA >> pool, and which is better [3]. >> >> However, as mentioned in [3], dma_alloc_coherent() uses the locality >> information from the device - as in direct DMA - so this patch is just >> applying this same policy. >> >> [1] https://lore.kernel.org/patchwork/patch/833004/ >> [2] https://lkml.org/lkml/2018/8/22/391 >> [3] >> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1692998.html >> >> >> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c >> index d1b0475..ada00bc 100644 >> --- a/drivers/iommu/dma-iommu.c >> +++ b/drivers/iommu/dma-iommu.c >> @@ -449,20 +449,17 @@ static void __iommu_dma_free_pages(struct page >> **pages, int count) >> kvfree(pages); >> } >> -static struct page **__iommu_dma_alloc_pages(unsigned int count, >> - unsigned long order_mask, gfp_t gfp) >> +static struct page **__iommu_dma_alloc_pages(struct device *dev, >> + unsigned int count, unsigned long order_mask, gfp_t gfp) >> { >> struct page **pages; >> - unsigned int i = 0, array_size = count * sizeof(*pages); >> + unsigned int i = 0, nid = dev_to_node(dev); >> order_mask &= (2U << MAX_ORDER) - 1; >> if (!order_mask) >> return NULL; >> - if (array_size <= PAGE_SIZE) >> - pages = kzalloc(array_size, GFP_KERNEL); >> - else >> - pages = vzalloc(array_size); >> + pages = kvzalloc_node(count * sizeof(*pages), GFP_KERNEL, nid); > > The pages array is only accessed by the CPU servicing the > iommu_dma_alloc() call, and is usually freed again before that call even > returns. It's certainly never touched by the device, so forcing it to a > potentially non-local node doesn't make a great deal of sense. Right, it seems sensible to not make this allocation include the device-locality requirement, so can leave as is. However modifying to use kvzalloc() would seem ok. > >> if (!pages) >> return NULL; >> @@ -483,8 +480,10 @@ static struct page >> **__iommu_dma_alloc_pages(unsigned int count, >> unsigned int order = __fls(order_mask); >> order_size = 1U << order; >> - page = alloc_pages((order_mask - order_size) ? >> - gfp | __GFP_NORETRY : gfp, order); >> + page = alloc_pages_node(nid, >> + (order_mask - order_size) ? >> + gfp | __GFP_NORETRY : gfp, >> + order); > > If we're touching this, can we sort out that horrendous ternary? FWIW I > found I have a local version of the original patch which I tweaked at > the time, and apparently I reworked this hunk as below, which does seem > somewhat nicer for the same diffstat. > > Robin. > > > @@ -446,10 +443,12 @@ static struct page > **__iommu_dma_alloc_pages(unsigned int count, > for (order_mask &= (2U << __fls(count)) - 1; > order_mask; order_mask &= ~order_size) { > unsigned int order = __fls(order_mask); > + gfp_t alloc_flags = gfp; > > order_size = 1U << order; > - page = alloc_pages((order_mask - order_size) ? > - gfp | __GFP_NORETRY : gfp, > order); > + if (order_size < order_mask) > + alloc_flags |= __GFP_NORETRY; Sure, this can be included > + page = alloc_pages_node(nid, alloc_flags, order); > if (!page) > continue; > if (!order) > > . > Cheers, John
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index d1b0475..ada00bc 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -449,20 +449,17 @@ static void __iommu_dma_free_pages(struct page **pages, int count) kvfree(pages); } -static struct page **__iommu_dma_alloc_pages(unsigned int count, - unsigned long order_mask, gfp_t gfp) +static struct page **__iommu_dma_alloc_pages(struct device *dev, + unsigned int count, unsigned long order_mask, gfp_t gfp) { struct page **pages; - unsigned int i = 0, array_size = count * sizeof(*pages); + unsigned int i = 0, nid = dev_to_node(dev); order_mask &= (2U << MAX_ORDER) - 1; if (!order_mask) return NULL; - if (array_size <= PAGE_SIZE) - pages = kzalloc(array_size, GFP_KERNEL); - else - pages = vzalloc(array_size); + pages = kvzalloc_node(count * sizeof(*pages), GFP_KERNEL, nid); if (!pages) return NULL; @@ -483,8 +480,10 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, unsigned int order = __fls(order_mask); order_size = 1U << order; - page = alloc_pages((order_mask - order_size) ? - gfp | __GFP_NORETRY : gfp, order); + page = alloc_pages_node(nid, + (order_mask - order_size) ? + gfp | __GFP_NORETRY : gfp, + order); if (!page) continue; if (!order) @@ -569,7 +568,8 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, alloc_sizes = min_size; count = PAGE_ALIGN(size) >> PAGE_SHIFT; - pages = __iommu_dma_alloc_pages(count, alloc_sizes >> PAGE_SHIFT, gfp); + pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT, + gfp); if (!pages) return NULL;