IB/core: dma unmap optimizations
authorGuy Shapiro <guysh@mellanox.com>
Wed, 15 Apr 2015 15:17:57 +0000 (18:17 +0300)
committerDoug Ledford <dledford@redhat.com>
Tue, 5 May 2015 13:18:02 +0000 (09:18 -0400)
commit325ad0617adaf163e32dd2d857b90baf65a25b5b
tree13383cd4f5442a70bff01f0f55d8007fcb03002a
parentc1d383b5785b1e0fb5fb862864712a7208219e6a
IB/core: dma unmap optimizations

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>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
drivers/infiniband/core/umem_odp.c