From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FB9BC5ACAE for ; Wed, 11 Sep 2019 15:15:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D22CA206A5 for ; Wed, 11 Sep 2019 15:15:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="eqkcSKVD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728427AbfIKPPA (ORCPT ); Wed, 11 Sep 2019 11:15:00 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:33492 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728182AbfIKPPA (ORCPT ); Wed, 11 Sep 2019 11:15:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=9Ts7UUugH0BhHT6ILLki/cYvYfh0gbGfHUwu1u4OVw8=; b=eqkcSKVD5dOJFE9++guNrEOku ugiFibAd7qPBNs79ndiqk4OEMfpM6jqG9pkL4/PgcpCNl1VtuKFn9391adW0g8KjDRn/2DrF+1J6U Gr9Qok/kye4rT8b59JEpXjUD5TFaVMr1dMKnWFC1eFVqzm5ygXtuFoyp951ixiriwwS5gwhbBLUJi U94832VbTPNeOBMMpu72U5QpaeSWUmS1XVcFXhor3uG9GgdzzMslZ209al1WCJl3Y5KcH8iybTCOv TzToz2C27tIJC0cWry7yAwavYapdb8V1G9AK2EhVnWeXkTXCF7FjLQo30x4oe8pVDHIWBOhdbjt8s XWUFtI3tQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.2 #3 (Red Hat Linux)) id 1i84KZ-0008Ht-S4; Wed, 11 Sep 2019 15:14:51 +0000 Date: Wed, 11 Sep 2019 08:14:51 -0700 From: Matthew Wilcox To: Waiman Long Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Alexander Viro , Mike Kravetz , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Davidlohr Bueso Subject: Re: [PATCH 5/5] hugetlbfs: Limit wait time when trying to share huge PMD Message-ID: <20190911151451.GH29434@bombadil.infradead.org> References: <20190911150537.19527-1-longman@redhat.com> <20190911150537.19527-6-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190911150537.19527-6-longman@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 11, 2019 at 04:05:37PM +0100, Waiman Long wrote: > When allocating a large amount of static hugepages (~500-1500GB) on a > system with large number of CPUs (4, 8 or even 16 sockets), performance > degradation (random multi-second delays) was observed when thousands > of processes are trying to fault in the data into the huge pages. The > likelihood of the delay increases with the number of sockets and hence > the CPUs a system has. This only happens in the initial setup phase > and will be gone after all the necessary data are faulted in. Can;t the application just specify MAP_POPULATE?