| Message ID | 1429111077-22739-3-git-send-email-guysh@mellanox.com (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
On 4/15/2015 6:17 PM, Guy Shapiro wrote: > While unmapping an ODP writable page, the dirty bit of the page is set. In > order to do so, the head of the compound page is found. > Currently, the compound head is found even on non-writable pages, where it is > never used, leading to unnecessary cpu barrier that impacts performance. > > This patch moves the search for the compound head to be done only when needed. > > Signed-off-by: Guy Shapiro <guysh@mellanox.com> > Acked-by: Shachar Raindel <raindel@mellanox.com> > --- > drivers/infiniband/core/umem_odp.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c > index aba4739..40becdb 100644 > --- a/drivers/infiniband/core/umem_odp.c > +++ b/drivers/infiniband/core/umem_odp.c > @@ -637,7 +637,6 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, > idx = (addr - ib_umem_start(umem)) / PAGE_SIZE; > if (umem->odp_data->page_list[idx]) { > struct page *page = umem->odp_data->page_list[idx]; > - struct page *head_page = compound_head(page); > dma_addr_t dma = umem->odp_data->dma_list[idx]; > dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK; > > @@ -645,7 +644,8 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, > > ib_dma_unmap_page(dev, dma_addr, PAGE_SIZE, > DMA_BIDIRECTIONAL); > - if (dma & ODP_WRITE_ALLOWED_BIT) > + if (dma & ODP_WRITE_ALLOWED_BIT) { > + struct page *head_page = compound_head(page); > /* > * set_page_dirty prefers being called with > * the page lock. However, MMU notifiers are > @@ -656,6 +656,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, > * be removed. > */ > set_page_dirty(head_page); Just a nit: The code is as readable with: set_page_dirty(compound_head(page)); and you relax the stack a little bit... Otherwise: Looks like a nice optimization. Reviewed-by: Sagi Grimberg <sagig@mellanox.com> -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c index aba4739..40becdb 100644 --- a/drivers/infiniband/core/umem_odp.c +++ b/drivers/infiniband/core/umem_odp.c @@ -637,7 +637,6 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, idx = (addr - ib_umem_start(umem)) / PAGE_SIZE; if (umem->odp_data->page_list[idx]) { struct page *page = umem->odp_data->page_list[idx]; - struct page *head_page = compound_head(page); dma_addr_t dma = umem->odp_data->dma_list[idx]; dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK; @@ -645,7 +644,8 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, ib_dma_unmap_page(dev, dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL); - if (dma & ODP_WRITE_ALLOWED_BIT) + if (dma & ODP_WRITE_ALLOWED_BIT) { + struct page *head_page = compound_head(page); /* * set_page_dirty prefers being called with * the page lock. However, MMU notifiers are @@ -656,6 +656,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, * be removed. */ set_page_dirty(head_page); + } /* on demand pinning support */ if (!umem->context->invalidate_range) put_page(page);