Date: Sun, 8 Mar 2009 21:48:29 +0000 (UTC) From: Robert Watson <rwatson@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/kern subr_witness.c uipc_usrreq.c Message-ID: <200903082148.n28LmYZ8034258@repoman.freebsd.org>
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rwatson 2009-03-08 21:48:29 UTC
FreeBSD src repository
Modified files:
sys/kern subr_witness.c uipc_usrreq.c
Log:
SVN rev 189544 on 2009-03-08 21:48:29Z by rwatson
Decompose the global UNIX domain sockets rwlock into two different
locks: a global list/counter/generation counter protected by a new
mutex unp_list_lock, and a global linkage rwlock, unp_global_rwlock,
which protects the connections between UNIX domain sockets.
This eliminates conditional lock acquisition that was previously a
property of the global lock being held over sonewconn() leading to a
call to uipc_attach(), which also required the global lock, but
couldn't rely on it as other paths existed to uipc_attach() that
didn't hold it: now uipc_attach() uses only the list lock, which
follows the linkage lock in the lock order. It may also reduce
contention on the global lock for some workloads.
Add global UNIX domain socket locks to hard-coded witness lock
order.
MFC after: 1 week
Discussed with: kris
Revision Changes Path
1.267 +2 -0 src/sys/kern/subr_witness.c
1.226 +96 -102 src/sys/kern/uipc_usrreq.c
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