From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 0E7F82808A3 for ; Wed, 10 May 2017 11:21:02 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id u12so27547910pgo.4 for ; Wed, 10 May 2017 08:21:02 -0700 (PDT) Received: from shards.monkeyblade.net (shards.monkeyblade.net. [184.105.139.130]) by mx.google.com with ESMTP id 3si3236507pfe.330.2017.05.10.08.21.01 for ; Wed, 10 May 2017 08:21:01 -0700 (PDT) Date: Wed, 10 May 2017 11:20:59 -0400 (EDT) Message-Id: <20170510.112059.169845404310247896.davem@davemloft.net> Subject: Re: [v3 0/9] parallelized "struct page" zeroing From: David Miller In-Reply-To: References: <3f5f1416-aa91-a2ff-cc89-b97fcaa3e4db@oracle.com> <20170510145726.GM31466@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: pasha.tatashin@oracle.com Cc: mhocko@kernel.org, linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, heiko.carstens@de.ibm.com From: Pasha Tatashin Date: Wed, 10 May 2017 11:01:40 -0400 > Perhaps you are right, and I will measure on x86. But, I suspect hit > can become unacceptable on some platfoms: there is an overhead of > calling a function, even if it is leaf-optimized, and there is an > overhead in memset() to check for alignments of size and address, > types of setting (zeroing vs. non-zeroing), etc., that adds up > quickly. Another source of overhead on the sparc64 side is that we much do memory barriers around the block initializiing stores. So batching calls to memset() amortize that as well. -- 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