On Mon, May 15, 2017 at 10:02:45AM +0000, Konstantin Belousov wrote: > Author: kib > Date: Mon May 15 10:02:45 2017 > New Revision: 318285 > URL: https://svnweb.freebsd.org/changeset/base/318285 > > Log: > mnt_vnode_next_active: use conventional lock order when trylock fails. > > Previously, when the VI_TRYLOCK failed, we would spin under the mutex > that protects the vnode active list until we either succeeded or > noticed that we had hogged the CPU. Since we were violating the lock > order, this would guarantee that we would become a hog under any > deadlock condition (e.g. a race with vdrop(9) on the same vnode). In > the presence of many concurrent threads in sync(2) or vdrop etc, the > victim could hang for a long time. > > Now, avoid spinning by dropping and reacquiring the locks in the > conventional lock order when the trylock fails. This requires a dance > with the vnode hold count. > > Submitted by: Tom Rix <t...@juniper.net> This must be Ryan Libby <rli...@gmail.com>, I am sorry.
> Tested by: pho > Differential revision: https://reviews.freebsd.org/D10692 _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
