linux-kernel - Re: [RFC 0/4]x86: allocate up to 32 tlb invalidate vectors

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 for Android: free password hash cracker in your pocket

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

Date:	Mon, 15 Nov 2010 22:02:45 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	lkml <linux-kernel@...r.kernel.org>
Cc:	Ingo Molnar <mingo@...e.hu>, Andi Kleen <andi@...stfloor.org>,
	"hpa@...or.com" <hpa@...or.com>
Subject: Re: [RFC 0/4]x86: allocate up to 32 tlb invalidate vectors

On Wed, 2010-11-03 at 14:44 +0800, Shaohua Li wrote:
> Hi,
> In workload with heavy page reclaim, flush_tlb_page() is frequently
> used. We currently have 8 vectors for tlb flush, which is fine for small
> machines. But for big machines with a lot of CPUs, the 8 vectors are
> shared by all CPUs and we need lock to protect them. This will cause a
> lot of lock contentions. please see the patch 3 for detailed number of
> the lock contention.
> Andi Kleen suggests we can use 32 vectors for tlb flush, which should be
> fine for even 8 socket machines. Test shows this reduces lock contention
> dramatically (see patch 3 for number).
> One might argue if this will waste too many vectors and leave less
> vectors for devices. This could be a problem. But even we use 32
> vectors, we still leave 78 vectors for devices. And we now have per-cpu
> vector, vector isn't scarce any more, but I'm open if anybody has
> objections.
> 
Hi Ingo & hpa, any comments about this series?

Thanks,
Shaohua

--
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/