From: Mike Marciniszyn Date: Fri, 23 Sep 2011 17:16:44 +0000 (-0400) Subject: IB/qib: Use RCU for qpn lookup X-Git-Tag: v3.2-rc1~104^2^11~5 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af061a644a0e4d4778fe6cd2246479c1962e153b;p=pandora-kernel.git IB/qib: Use RCU for qpn lookup The heavy weight spinlock in qib_lookup_qpn() is replaced with RCU. The hash list itself is now accessed via jhash functions instead of mod. The changes should benefit multiple receive contexts in different processors by not contending for the lock just to read the hash structures. The patch also adds a lookaside_qp (pointer) and a lookaside_qpn in the context. The interrupt handler will test the current packet's qpn against lookaside_qpn if the lookaside_qp pointer is non-NULL. The pointer is NULL'ed when the interrupt handler exits. Signed-off-by: Mike Marciniszyn Signed-off-by: Roland Dreier --- Reading git-diff-tree failed