netdev - Re: [PATCH 3/6] fs: Introduce a per_cpu last

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: <20081127094615.GC13860@infradead.org>
Date:	Thu, 27 Nov 2008 04:46:15 -0500
From:	Christoph Hellwig <hch@...radead.org>
To:	Eric Dumazet <dada1@...mosbay.com>
Cc:	Ingo Molnar <mingo@...e.hu>, David Miller <davem@...emloft.net>,
	"Rafael J. Wysocki" <rjw@...k.pl>, linux-kernel@...r.kernel.org,
	kernel-testers@...r.kernel.org, Mike Galbraith <efault@....de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Linux Netdev List <netdev@...r.kernel.org>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH 3/6] fs: Introduce a per_cpu last_ino allocator

On Thu, Nov 27, 2008 at 12:32:24AM +0100, Eric Dumazet wrote:
> new_inode() dirties a contended cache line to get inode numbers.
>
> Solve this problem by providing to each cpu a per_cpu variable,
> feeded by the shared last_ino, but once every 1024 allocations.
>
> This reduce contention on the shared last_ino.
>
> Note : last_ino_get() method must be called with preemption
> disabled on SMP.

Looks a little clumsy.  One idea might be to have a special slab for
synthetic inodes using new_inode and only assign it on the first
allocation and after that re-use it.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html