From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f69.google.com (mail-lf0-f69.google.com [209.85.215.69]) by kanga.kvack.org (Postfix) with ESMTP id 4D01D280250 for ; Thu, 22 Sep 2016 08:37:59 -0400 (EDT) Received: by mail-lf0-f69.google.com with SMTP id b71so54288588lfg.2 for ; Thu, 22 Sep 2016 05:37:59 -0700 (PDT) Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com. [74.125.82.68]) by mx.google.com with ESMTPS id te1si1687107wjb.41.2016.09.22.05.37.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Sep 2016 05:37:38 -0700 (PDT) Received: by mail-wm0-f68.google.com with SMTP id w84so13846642wmg.0 for ; Thu, 22 Sep 2016 05:37:38 -0700 (PDT) Date: Thu, 22 Sep 2016 14:37:36 +0200 From: Michal Hocko Subject: Re: [PATCH 3/5] mm/vmalloc.c: correct lazy_max_pages() return value Message-ID: <20160922123736.GA11204@dhcp22.suse.cz> References: <57E20C49.8010304@zoho.com> <3ef46c24-769d-701a-938b-826f4249bf0b@zoho.com> <57E3304E.4060401@zoho.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57E3304E.4060401@zoho.com> Sender: owner-linux-mm@kvack.org List-ID: To: zijun_hu Cc: David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, zijun_hu@htc.com, Andrew Morton , tj@kernel.org, mingo@kernel.org, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net On Thu 22-09-16 09:13:50, zijun_hu wrote: > On 09/22/2016 08:35 AM, David Rientjes wrote: [...] > > The intent is as it is implemented; with your change, lazy_max_pages() is > > potentially increased depending on the number of online cpus. This is > > only a heuristic, changing it would need justification on why the new > > value is better. It is opposite to what the comment says: "to be > > conservative and not introduce a big latency on huge systems, so go with > > a less aggressive log scale." NACK to the patch. > > > my change potentially make lazy_max_pages() decreased not increased, i seems > conform with the comment > > if the number of online CPUs is not power of 2, both have no any difference > otherwise, my change remain power of 2 value, and the original code rounds up > to next power of 2 value, for instance > > my change : (32, 64] -> 64 > 32 -> 32, 64 -> 64 > the original code: [32, 63) -> 64 > 32 -> 64, 64 -> 128 You still completely failed to explain _why_ this is an improvement/fix or why it matters. This all should be in the changelog. -- Michal Hocko 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