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[216.228.121.64]) by mx.google.com with ESMTPS id p14si6467679pfn.267.2019.04.19.16.09.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Apr 2019 16:09:52 -0700 (PDT) Received-SPF: pass (google.com: domain of rcampbell@nvidia.com designates 216.228.121.64 as permitted sender) client-ip=216.228.121.64; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=naKeu+d4; spf=pass (google.com: domain of rcampbell@nvidia.com designates 216.228.121.64 as permitted sender) smtp.mailfrom=rcampbell@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 19 Apr 2019 16:09:29 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 19 Apr 2019 16:09:51 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 19 Apr 2019 16:09:51 -0700 Received: from rcampbell-dev.nvidia.com (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 19 Apr 2019 23:09:51 +0000 Subject: Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal To: Dan Williams , CC: Michal Hocko , Vlastimil Babka , Logan Gunthorpe , , , , References: <155552633539.2015392.2477781120122237934.stgit@dwillia2-desk3.amr.corp.intel.com> <155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com> From: Ralph Campbell Message-ID: <001f15a6-26bb-cbab-587f-d897b2dc9094@nvidia.com> Date: Fri, 19 Apr 2019 16:09:51 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.0 MIME-Version: 1.0 In-Reply-To: <155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1555715370; bh=LsXD0klpMTgpZM/8Qdv7cRMawphkfxNMAjiWA9I1AKk=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=naKeu+d4gLKnO5C+DmaZOCySBAoJ8cnyIa7Zr53HUzI9uYduIhZ1k2Arw1neNJcdn aR+9Tv/IC6YDMK/wVL9YN1vtgnb0vP9YXGs5ivCcr/3cbfnKeMHGteKPNTpi58wYbB ipGbxXkNE7Gt0GK5OYE40P0YsZMCe2FrS7HQZB79Dj3cyL1cU/PA2Z1sJQFa3dX4wE bd2gwNrqZveXL7PvMzhmlhH1VhC/W/NTxXIbhBgI+iQ9pGqcELanGfC31bknXs/rGX wBxEJxxe4sKIxV9tYKJQqCceUIq9hxLGhbm4+NYeiVn7J8LWXu6zC/iPCTWpPy7Ndp V67k15WSlznHg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Just noticed this by inspection. I can't say I'm very familiar with the code. On 4/17/19 11:39 AM, Dan Williams wrote: > Sub-section hotplug support reduces the unit of operation of hotplug > from section-sized-units (PAGES_PER_SECTION) to sub-section-sized units > (PAGES_PER_SUBSECTION). Teach shrink_{zone,pgdat}_span() to consider > PAGES_PER_SUBSECTION boundaries as the points where pfn_valid(), not > valid_section(), can toggle. > > Cc: Michal Hocko > Cc: Vlastimil Babka > Cc: Logan Gunthorpe > Signed-off-by: Dan Williams > --- > include/linux/mmzone.h | 2 ++ > mm/memory_hotplug.c | 16 ++++++++-------- > 2 files changed, 10 insertions(+), 8 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index cffde898e345..b13f0cddf75e 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1164,6 +1164,8 @@ static inline unsigned long section_nr_to_pfn(unsigned long sec) > > #define SECTION_ACTIVE_SIZE ((1UL << SECTION_SIZE_BITS) / BITS_PER_LONG) > #define SECTION_ACTIVE_MASK (~(SECTION_ACTIVE_SIZE - 1)) > +#define PAGES_PER_SUB_SECTION (SECTION_ACTIVE_SIZE / PAGE_SIZE) > +#define PAGE_SUB_SECTION_MASK (~(PAGES_PER_SUB_SECTION-1)) > > struct mem_section_usage { > /* > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 8b7415736d21..d5874f9d4043 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -327,10 +327,10 @@ static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, > { > struct mem_section *ms; > > - for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) { > + for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUB_SECTION) { > ms = __pfn_to_section(start_pfn); > > - if (unlikely(!valid_section(ms))) > + if (unlikely(!pfn_valid(start_pfn))) > continue; Note that "struct mem_section *ms;" is now set but not used. You can remove the definition and initialization of "ms". > if (unlikely(pfn_to_nid(start_pfn) != nid)) > @@ -355,10 +355,10 @@ static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, > > /* pfn is the end pfn of a memory section. */ > pfn = end_pfn - 1; > - for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) { > + for (; pfn >= start_pfn; pfn -= PAGES_PER_SUB_SECTION) { > ms = __pfn_to_section(pfn); > > - if (unlikely(!valid_section(ms))) > + if (unlikely(!pfn_valid(pfn))) > continue; Ditto about "ms". > if (unlikely(pfn_to_nid(pfn) != nid)) > @@ -417,10 +417,10 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, > * it check the zone has only hole or not. > */ > pfn = zone_start_pfn; > - for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) { > + for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUB_SECTION) { > ms = __pfn_to_section(pfn); > > - if (unlikely(!valid_section(ms))) > + if (unlikely(!pfn_valid(pfn))) > continue; Ditto about "ms". > if (page_zone(pfn_to_page(pfn)) != zone) > @@ -485,10 +485,10 @@ static void shrink_pgdat_span(struct pglist_data *pgdat, > * has only hole or not. > */ > pfn = pgdat_start_pfn; > - for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) { > + for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUB_SECTION) { > ms = __pfn_to_section(pfn); > > - if (unlikely(!valid_section(ms))) > + if (unlikely(!pfn_valid(pfn))) > continue; Ditto about "ms". > if (pfn_to_nid(pfn) != nid) >