From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (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 DFAF22128D698 for ; Mon, 17 Jun 2019 18:42:48 -0700 (PDT) Date: Tue, 18 Jun 2019 09:42:23 +0800 From: Wei Yang Subject: Re: [PATCH v9 03/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal Message-ID: <20190618014223.GD18161@richard> References: <155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com> <155977188458.2443951.9573565800736334460.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <155977188458.2443951.9573565800736334460.stgit@dwillia2-desk3.amr.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Wei Yang Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: mhocko@suse.com, Pavel Tatashin , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, Vlastimil Babka , osalvador@suse.de List-ID: On Wed, Jun 05, 2019 at 02:58:04PM -0700, 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 >Reviewed-by: Pavel Tatashin >Reviewed-by: Oscar Salvador >Signed-off-by: Dan Williams >--- > mm/memory_hotplug.c | 29 ++++++++--------------------- > 1 file changed, 8 insertions(+), 21 deletions(-) > >diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >index 7b963c2d3a0d..647859a1d119 100644 >--- a/mm/memory_hotplug.c >+++ b/mm/memory_hotplug.c >@@ -318,12 +318,8 @@ static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, > unsigned long start_pfn, > unsigned long end_pfn) > { >- struct mem_section *ms; >- >- for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) { >- ms = __pfn_to_section(start_pfn); >- >- if (unlikely(!valid_section(ms))) >+ for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { >+ if (unlikely(!pfn_valid(start_pfn))) > continue; Hmm, we change the granularity of valid section from SECTION to SUBSECTION. But we didn't change the granularity of node id and zone information. For example, we found the node id of a pfn mismatch, we can skip the whole section instead of a subsection. Maybe this is not a big deal. > > if (unlikely(pfn_to_nid(start_pfn) != nid)) >@@ -343,15 +339,12 @@ static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, > unsigned long start_pfn, > unsigned long end_pfn) > { >- struct mem_section *ms; > unsigned long pfn; > > /* pfn is the end pfn of a memory section. */ > pfn = end_pfn - 1; >- for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) { >- ms = __pfn_to_section(pfn); >- >- if (unlikely(!valid_section(ms))) >+ for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { >+ if (unlikely(!pfn_valid(pfn))) > continue; > > if (unlikely(pfn_to_nid(pfn) != nid)) >@@ -373,7 +366,6 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, > unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */ > unsigned long zone_end_pfn = z; > unsigned long pfn; >- struct mem_section *ms; > int nid = zone_to_nid(zone); > > zone_span_writelock(zone); >@@ -410,10 +402,8 @@ 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) { >- ms = __pfn_to_section(pfn); >- >- if (unlikely(!valid_section(ms))) >+ for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) { >+ if (unlikely(!pfn_valid(pfn))) > continue; > > if (page_zone(pfn_to_page(pfn)) != zone) >@@ -441,7 +431,6 @@ static void shrink_pgdat_span(struct pglist_data *pgdat, > unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */ > unsigned long pgdat_end_pfn = p; > unsigned long pfn; >- struct mem_section *ms; > int nid = pgdat->node_id; > > if (pgdat_start_pfn == start_pfn) { >@@ -478,10 +467,8 @@ 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) { >- ms = __pfn_to_section(pfn); >- >- if (unlikely(!valid_section(ms))) >+ for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUBSECTION) { >+ if (unlikely(!pfn_valid(pfn))) > continue; > > if (pfn_to_nid(pfn) != nid) > >_______________________________________________ >Linux-nvdimm mailing list >Linux-nvdimm@lists.01.org >https://lists.01.org/mailman/listinfo/linux-nvdimm -- Wei Yang Help you, Help me _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm