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authorOr Gerlitz <ogerlitz@mellanox.com>2014-05-11 15:15:11 +0300
committerRoland Dreier <roland@purestorage.com>2014-06-02 14:58:11 -0700
commit09b93088d75009807b72293f26e2634430ce5ba9 (patch)
tree78337f035d708879589063e779c5fa3a42183c2e /include/rdma
parent60093dc0c8b6407bc7494cbcb3e84322cc6782c8 (diff)
downloadlinux-linaro-stable-09b93088d75009807b72293f26e2634430ce5ba9.tar.gz
IB: Add a QP creation flag to use GFP_NOIO allocations
This addresses a problem where NFS client writes over IPoIB connected mode may deadlock on memory allocation/writeback. The problem is not directly memory reclamation. There is an indirect dependency between network filesystems writing back pages and ipoib_cm_tx_init() due to how a kworker is used. Page reclaim cannot make forward progress until ipoib_cm_tx_init() succeeds and it is stuck in page reclaim itself waiting for network transmission. Ordinarily this situation may be avoided by having the caller use GFP_NOFS but ipoib_cm_tx_init() does not have that information. To address this, take a general approach and add a new QP creation flag that tells the low-level hardware driver to use GFP_NOIO for the memory allocations related to the new QP. Use the new flag in the ipoib connected mode path, and if the driver doesn't support it, re-issue the QP creation without the flag. Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'include/rdma')
-rw-r--r--include/rdma/ib_verbs.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index acd825182977..d75b02f9c80d 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -783,6 +783,7 @@ enum ib_qp_create_flags {
IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK = 1 << 1,
IB_QP_CREATE_NETIF_QP = 1 << 5,
IB_QP_CREATE_SIGNATURE_EN = 1 << 6,
+ IB_QP_CREATE_USE_GFP_NOIO = 1 << 7,
/* reserve bits 26-31 for low level drivers' internal use */
IB_QP_CREATE_RESERVED_START = 1 << 26,
IB_QP_CREATE_RESERVED_END = 1 << 31,