From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id E26F96B0253 for ; Mon, 9 Jan 2017 11:00:17 -0500 (EST) Received: by mail-it0-f71.google.com with SMTP id x2so93203543itf.6 for ; Mon, 09 Jan 2017 08:00:17 -0800 (PST) Received: from mail-io0-x231.google.com (mail-io0-x231.google.com. [2607:f8b0:4001:c06::231]) by mx.google.com with ESMTPS id o189si9835893ith.38.2017.01.09.08.00.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Jan 2017 08:00:17 -0800 (PST) Received: by mail-io0-x231.google.com with SMTP id f103so85395590ioi.1 for ; Mon, 09 Jan 2017 08:00:17 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20170109102219.GF7495@dhcp22.suse.cz> References: <20170106152052.GS5556@dhcp22.suse.cz> <20170106160743.GU5556@dhcp22.suse.cz> <20170106161944.GW5556@dhcp22.suse.cz> <20170109102219.GF7495@dhcp22.suse.cz> From: Eric Dumazet Date: Mon, 9 Jan 2017 08:00:16 -0800 Message-ID: Subject: Re: __GFP_REPEAT usage in fq_alloc_node Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, LKML On Mon, Jan 9, 2017 at 2:22 AM, Michal Hocko wrote: > > the changelog doesn't mention it but this, unlike other kvmalloc > conversions is not without functional changes. The kmalloc part > will be weaker than it is with the original code for !costly (<64kB) > requests, because we are enforcing __GFP_NORETRY to break out from the > page allocator which doesn't really fail such a small requests. > > Now the question is what those code paths really prefer. Do they really > want to potentially loop in the page allocator and invoke the OOM killer > when the memory is short/fragmeted? I mean we can get into a situation > when no order-3 pages can be compacted and shooting the system down just > for that reason sounds quite dangerous to me. > > So the main question is how hard should we try before falling back to > vmalloc here? This patch is fine : 1) Default hash size is 1024 slots, 8192 bytes on 64bit arches. 2) Most of the times, qdisc are setup at boot time. -- 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