From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id F406F6B0038 for ; Mon, 13 Feb 2017 05:05:33 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id h7so41136910wjy.6 for ; Mon, 13 Feb 2017 02:05:33 -0800 (PST) Received: from outbound-smtp08.blacknight.com (outbound-smtp08.blacknight.com. [46.22.139.13]) by mx.google.com with ESMTPS id 196si4910990wmg.65.2017.02.13.02.05.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 Feb 2017 02:05:32 -0800 (PST) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp08.blacknight.com (Postfix) with ESMTPS id 2696C1C174A for ; Mon, 13 Feb 2017 10:05:32 +0000 (GMT) Date: Mon, 13 Feb 2017 10:05:31 +0000 From: Mel Gorman Subject: Re: PCID review? Message-ID: <20170213100531.giv4rlihqid6ocz4@techsingularity.net> References: <20170209001042.ahxmoqegr6h74mle@techsingularity.net> <20170210110157.dlejz7szrj3r3pwq@techsingularity.net> <20170210215708.j54cawm23nepgimd@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: Andy Lutomirski , Nadav Amit , Borislav Petkov , Kees Cook , Dave Hansen , "linux-mm@kvack.org" , "Paul E. McKenney" On Fri, Feb 10, 2017 at 02:07:19PM -0800, Andy Lutomirski wrote: > > Ok, probably for the best albeit that is based on an inability to figure > > out how it could be done efficiently and a suspicion that if it could be > > done, the scheduler would be doing it already. > > > > FWIW, I am doing a bit of this. For remote CPUs that aren't currently > running a given mm, I just bump a per-mm generation count so that they > know to flush next time around in switch_mm(). I'll need to add a new > hook to the batched flush code to get this right, and I'll cc you on > that. Stay tuned. > Ok, thanks. > > [1] I could be completely wrong, I'm basing this on how people have > > behaved in the past during TLB-flush related discussions. They > > might have changed their mind. > > We'll see. The main benchmark that I'm relying on (so far) is that > context switches get way faster, just ping ponging back and forth. I > suspect that the TLB refill cost is only a small part. > Note that such a benchmark is not going to measure the TLB flush cost. In itself, this is not bad but I suspect that the applications that care about interference from TLB flushes by unrelated processes are not applications that are context-switch intensive. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org