From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id 292386B0269 for ; Wed, 17 Oct 2018 05:11:57 -0400 (EDT) Received: by mail-ed1-f70.google.com with SMTP id x10-v6so16323736edx.9 for ; Wed, 17 Oct 2018 02:11:57 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id y37-v6si11609405edd.10.2018.10.17.02.11.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 17 Oct 2018 02:11:55 -0700 (PDT) Date: Wed, 17 Oct 2018 11:11:54 +0200 From: Michal Hocko Subject: Re: [mm PATCH v3 3/6] mm: Use memblock/zone specific iterator for handling deferred page init Message-ID: <20181017091154.GK18839@dhcp22.suse.cz> References: <20181015202456.2171.88406.stgit@localhost.localdomain> <20181015202709.2171.75580.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181015202709.2171.75580.stgit@localhost.localdomain> Sender: owner-linux-mm@kvack.org List-ID: To: Alexander Duyck Cc: linux-mm@kvack.org, akpm@linux-foundation.org, pavel.tatashin@microsoft.com, dave.jiang@intel.com, linux-kernel@vger.kernel.org, willy@infradead.org, davem@davemloft.net, yi.z.zhang@linux.intel.com, khalid.aziz@oracle.com, rppt@linux.vnet.ibm.com, vbabka@suse.cz, sparclinux@vger.kernel.org, dan.j.williams@intel.com, ldufour@linux.vnet.ibm.com, mgorman@techsingularity.net, mingo@kernel.org, kirill.shutemov@linux.intel.com On Mon 15-10-18 13:27:09, Alexander Duyck wrote: > This patch introduces a new iterator for_each_free_mem_pfn_range_in_zone. > > This iterator will take care of making sure a given memory range provided > is in fact contained within a zone. It takes are of all the bounds checking > we were doing in deferred_grow_zone, and deferred_init_memmap. In addition > it should help to speed up the search a bit by iterating until the end of a > range is greater than the start of the zone pfn range, and will exit > completely if the start is beyond the end of the zone. > > This patch adds yet another iterator called > for_each_free_mem_range_in_zone_from and then uses it to support > initializing and freeing pages in groups no larger than MAX_ORDER_NR_PAGES. > By doing this we can greatly improve the cache locality of the pages while > we do several loops over them in the init and freeing process. > > We are able to tighten the loops as a result since we only really need the > checks for first_init_pfn in our first iteration and after that we can > assume that all future values will be greater than this. So I have added a > function called deferred_init_mem_pfn_range_in_zone that primes the > iterators and if it fails we can just exit. Numbers please. Besides that, this adds a lot of code and I am not convinced the result is so much better to justify that. > Signed-off-by: Alexander Duyck > --- > include/linux/memblock.h | 58 +++++++++++++++ > mm/memblock.c | 63 ++++++++++++++++ > mm/page_alloc.c | 176 ++++++++++++++++++++++++++++++++-------------- > 3 files changed, 242 insertions(+), 55 deletions(-) -- Michal Hocko SUSE Labs