linux-kernel - Re: [PATCH] fs/proc: Move kfree outside pde_unload

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]

Date:	Fri, 24 Aug 2012 09:48:52 -0500
From:	Nathan Zimmer <nzimmer@....com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Nathan Zimmer <nzimmer@....com>, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, adobriyan@...il.com,
	Alexander Viro <viro@...iv.linux.org.uk>,
	David Woodhouse <dwmw2@...radead.org>
Subject: Re: [PATCH] fs/proc: Move kfree outside pde_unload_lock

On Wed, Aug 22, 2012 at 11:42:58PM +0200, Eric Dumazet wrote:
> On Wed, 2012-08-22 at 20:28 +0200, Eric Dumazet wrote:
> 
> > 
> > Thats interesting, but if you really want this to fly, one RCU
> > conversion would be much better ;)
> > 
> > pde_users would be an atomic_t and you would avoid the spinlock
> > contention.
> 
> Here is what I had in mind, I would be interested to know how it helps a 512 core machine ;)
> 

Here are the results and they look great.

cpuinfo	baseline	moved kfree	Rcu 
tasks	read-sec	read-sec	read-sec
1	0.0141		0.0141		0.0141
2	0.0140		0.0140		0.0142
4	0.0140		0.0141		0.0141
8	0.0145		0.0145		0.0140
16	0.0553		0.0548		0.0168
32	0.1688		0.1622		0.0549
64	0.5017		0.3856		0.1690
128	1.7005		0.9710		0.5038
256	5.2513		2.6519		2.0804
512	8.0529		6.2976		3.0162



--
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/