From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 6B12628026B for ; Mon, 26 Sep 2016 21:38:47 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id 21so422514141pfy.3 for ; Mon, 26 Sep 2016 18:38:47 -0700 (PDT) Received: from mail-pf0-x243.google.com (mail-pf0-x243.google.com. [2607:f8b0:400e:c00::243]) by mx.google.com with ESMTPS id t9si27252876pal.288.2016.09.26.18.38.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Sep 2016 18:38:46 -0700 (PDT) Received: by mail-pf0-x243.google.com with SMTP id 6so9845149pfl.2 for ; Mon, 26 Sep 2016 18:38:46 -0700 (PDT) Message-ID: <1474940324.28155.44.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [PATCH v2] fs/select: add vmalloc fallback for select(2) From: Eric Dumazet Date: Mon, 26 Sep 2016 18:38:44 -0700 In-Reply-To: <20160926170105.517f74cd67ecdd5ef73e1865@linux-foundation.org> References: <20160922164359.9035-1-vbabka@suse.cz> <20160926170105.517f74cd67ecdd5ef73e1865@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Vlastimil Babka , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , netdev@vger.kernel.org On Mon, 2016-09-26 at 17:01 -0700, Andrew Morton wrote: > I don't share Eric's concerns about performance here. If the vmalloc() > is called, we're about to write to that quite large amount of memory > which we just allocated, and the vmalloc() overhead will be relatively > low. I did not care of the performance of this particular select() system call really, but other cpus because of more TLB invalidations. At least CONFIG_DEBUG_PAGEALLOC=y builds should be impacted, but maybe we do not care. -- 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