linux-kernel - Re: [RFC][PATCH 12/13] stop

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150624154010.GS19282@twins.programming.kicks-ass.net>
Date:	Wed, 24 Jun 2015 17:40:10 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	Oleg Nesterov <oleg@...hat.com>, tj@...nel.org, mingo@...hat.com,
	linux-kernel@...r.kernel.org, der.herr@...r.at, dave@...olabs.net,
	riel@...hat.com, viro@...IV.linux.org.uk,
	torvalds@...ux-foundation.org
Subject: Re: [RFC][PATCH 12/13] stop_machine: Remove lglock

On Wed, Jun 24, 2015 at 08:27:19AM -0700, Paul E. McKenney wrote:
> > The thing is, if we're stalled on a stop_one_cpu() call, the sync_rcu()
> > is equally stalled. The sync_rcu() cannot wait more efficient than we're
> > already waiting either.
> 
> Ah, but synchronize_rcu() doesn't force waiting on more than one extra
> grace period.  With strictly queued mutex, you can end up waiting on
> several.

But you could fix that by replacing/augmenting the expedited ticket with
gpnum/copmleted as used in get_state_synchronize_rcu()/cond_synchronize_rcu().


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/