From: Ralph Campbell <rcampbell@nvidia.com>
To: Dan Williams <dan.j.williams@intel.com>, <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Logan Gunthorpe <logang@deltatee.com>, <linux-mm@kvack.org>,
<linux-nvdimm@lists.01.org>, <linux-kernel@vger.kernel.org>,
<david@redhat.com>
Subject: Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal
Date: Fri, 19 Apr 2019 16:09:51 -0700 [thread overview]
Message-ID: <001f15a6-26bb-cbab-587f-d897b2dc9094@nvidia.com> (raw)
In-Reply-To: <155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com>
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 <mhocko@suse.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> 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)
>
next prev parent reply other threads:[~2019-04-19 23:09 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 18:38 [PATCH v6 00/12] mm: Sub-section memory hotplug support Dan Williams
2019-04-17 18:39 ` [PATCH v6 01/12] mm/sparsemem: Introduce struct mem_section_usage Dan Williams
2019-05-01 23:25 ` Pavel Tatashin
2019-05-02 6:07 ` Dan Williams
2019-05-02 14:16 ` Pavel Tatashin
2019-05-04 0:22 ` Dan Williams
2019-05-04 15:55 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 02/12] mm/sparsemem: Introduce common definitions for the size and mask of a section Dan Williams
2019-05-02 14:53 ` Pavel Tatashin
2019-05-03 0:41 ` Dan Williams
2019-05-03 10:35 ` Robin Murphy
2019-05-03 12:57 ` Pavel Tatashin
2019-05-03 13:00 ` Oscar Salvador
2019-04-17 18:39 ` [PATCH v6 03/12] mm/sparsemem: Add helpers track active portions of a section at boot Dan Williams
2019-04-25 14:33 ` Oscar Salvador
2019-04-25 14:43 ` Oscar Salvador
2019-04-26 12:57 ` Oscar Salvador
2019-05-02 16:12 ` Pavel Tatashin
2019-05-04 19:26 ` Dan Williams
2019-04-17 18:39 ` [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal Dan Williams
2019-04-19 23:09 ` Ralph Campbell [this message]
2019-04-19 23:13 ` Dan Williams
2019-04-26 13:59 ` Oscar Salvador
2019-04-26 14:00 ` Oscar Salvador
2019-05-02 19:18 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 05/12] mm/sparsemem: Convert kmalloc_section_memmap() to populate_section_memmap() Dan Williams
2019-05-02 19:28 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 06/12] mm/hotplug: Add mem-hotplug restrictions for remove_memory() Dan Williams
2019-04-23 21:21 ` David Hildenbrand
2019-04-24 18:07 ` Dan Williams
2019-04-17 18:39 ` [PATCH v6 07/12] mm: Kill is_dev_zone() helper Dan Williams
2019-04-17 20:17 ` David Hildenbrand
2019-04-26 14:04 ` Oscar Salvador
2019-05-02 20:37 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 08/12] mm/sparsemem: Prepare for sub-section ranges Dan Williams
2019-05-02 21:25 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 09/12] mm/sparsemem: Support sub-section hotplug Dan Williams
2019-04-17 18:39 ` [PATCH v6 10/12] mm/devm_memremap_pages: Enable sub-section remap Dan Williams
2019-04-17 18:39 ` [PATCH v6 11/12] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields Dan Williams
2019-04-17 22:02 ` Andrew Morton
2019-04-17 22:09 ` Dan Williams
2019-04-17 18:39 ` [PATCH v6 12/12] libnvdimm/pfn: Stop padding pmem namespaces to section alignment Dan Williams
2019-04-17 22:03 ` [PATCH v6 00/12] mm: Sub-section memory hotplug support Andrew Morton
2019-04-17 22:59 ` Dan Williams
2019-04-18 2:09 ` Dan Williams
2019-04-18 12:45 ` Jeff Moyer
2019-04-19 3:25 ` Dan Williams
2019-04-23 13:16 ` Oscar Salvador
2019-04-24 20:43 ` Pavel Tatashin
2019-05-02 22:46 ` Pavel Tatashin
2019-05-02 23:20 ` Dan Williams
2019-05-02 23:21 ` Dan Williams
2019-05-03 10:48 ` Oscar Salvador
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