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]
Date:	Wed, 18 Jun 2014 21:52:25 -0700
From:	Eric Dumazet <>
To:	Andi Kleen <>
Cc:	"Paul E. McKenney" <>,
	Dave Hansen <>,
	LKML <>,
	Josh Triplett <>,
	"Chen, Tim C" <>,
	Christoph Lameter <>
Subject: Re: [bisected] pre-3.16 regression on open() scalability

On Wed, 2014-06-18 at 20:38 -0700, Andi Kleen wrote:
> On Wed, Jun 18, 2014 at 07:13:37PM -0700, Paul E. McKenney wrote:
> > On Wed, Jun 18, 2014 at 06:42:00PM -0700, Andi Kleen wrote:
> > > 
> > > I still think it's totally the wrong direction to pollute so 
> > > many fast paths with this obscure debugging check workaround
> > > unconditionally.
> > 
> > OOM prevention should count for something, I would hope.
> OOM in what scenario? This is getting bizarre.
> If something keeps looping forever in the kernel creating 
> RCU callbacks without any real quiescent states it's simply broken.

Typical problem we faced in the past is in exit() path when multi
thousands of files/sockets are rcu-freed, and qhimark is hit.

Huge latency alerts, as freeing 10000+ items takes a while (about 70 ns
per item...)

Maybe close_files() should use a
cond_resched_and_keep_rcu_queues_small_please() ;)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists