Messages in this thread | | | Subject | Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal | From | Ralph Campbell <> | Date | Fri, 19 Apr 2019 16:09:51 -0700 |
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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) >
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