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Commit c1d383b5 authored by Guy Shapiro's avatar Guy Shapiro Committed by Doug Ledford
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IB/core: dma map/unmap locking optimizations 



Currently, while mapping or unmapping pages for ODP, the umem mutex is locked
and unlocked once for each page. Such lock/unlock operation take few tens to
hundreds of nsecs. This makes a significant impact when mapping or unmapping few
MBs of memory.

To avoid this, the mutex should be locked only once per operation, and not per
page.

Signed-off-by: default avatarGuy Shapiro <guysh@mellanox.com>
Acked-by: default avatarShachar Raindel <raindel@mellanox.com>
Reviewed-by: default avatarSagi Grimberg <sagig@mellanox.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 5b6b8fe6

drivers/infiniband/core/umem_odp.c

+4 −5
Original line number Diff line number Diff line
@@ -446,7 +446,6 @@ static int ib_umem_odp_map_dma_single_page( 
	int remove_existing_mapping = 0;

	int ret = 0;



	mutex_lock(&umem->odp_data->umem_mutex);

	/*

	 * Note: we avoid writing if seq is different from the initial seq, to

	 * handle case of a racing notifier. This check also allows us to bail
@@ -479,8 +478,6 @@ static int ib_umem_odp_map_dma_single_page( 
	}



out:

	mutex_unlock(&umem->odp_data->umem_mutex);



	/* On Demand Paging - avoid pinning the page */

	if (umem->context->invalidate_range || !stored_page)

		put_page(page);
@@ -586,6 +583,7 @@ int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt, 


		bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);

		user_virt += npages << PAGE_SHIFT;

		mutex_lock(&umem->odp_data->umem_mutex);

		for (j = 0; j < npages; ++j) {

			ret = ib_umem_odp_map_dma_single_page(

				umem, k, base_virt_addr, local_page_list[j],
@@ -594,6 +592,7 @@ int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt, 
				break;

			k++;

		}

		mutex_unlock(&umem->odp_data->umem_mutex);



		if (ret < 0) {

			/* Release left over pages when handling errors. */
@@ -633,9 +632,9 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, 
	 * faults from completion. We might be racing with other

	 * invalidations, so we must make sure we free each page only

	 * once. */

	mutex_lock(&umem->odp_data->umem_mutex);

	for (addr = virt; addr < bound; addr += (u64)umem->page_size) {

		idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;

		mutex_lock(&umem->odp_data->umem_mutex);

		if (umem->odp_data->page_list[idx]) {

			struct page *page = umem->odp_data->page_list[idx];

			struct page *head_page = compound_head(page);
@@ -663,7 +662,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, 
			umem->odp_data->page_list[idx] = NULL;

			umem->odp_data->dma_list[idx] = 0;

		}

		mutex_unlock(&umem->odp_data->umem_mutex);

	}

	mutex_unlock(&umem->odp_data->umem_mutex);

}

EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);