From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hqemgate15.nvidia.com (hqemgate15.nvidia.com [216.228.121.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id BD32B2194EB7F for ; Fri, 19 Apr 2019 16:09:52 -0700 (PDT) Subject: Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal 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 MIME-Version: 1.0 In-Reply-To: <155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams , akpm@linux-foundation.org Cc: Michal Hocko , linux-nvdimm@lists.01.org, david@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Vlastimil Babka 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) > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm