| Message ID | 155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: Sub-section memory hotplug support | expand |
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) >
On Fri, Apr 19, 2019 at 4:09 PM Ralph Campbell <rcampbell@nvidia.com> wrote: [..] > > 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". Good eye, yes, will clean up.
On Wed, Apr 17, 2019 at 11:39:16AM -0700, Dan Williams wrote: > @@ -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; > > 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; > > if (pfn_to_nid(pfn) != nid) The last loop from shrink_{pgdat,zone}_span can be reworked to unify both in one function, and both functions can be factored out a bit. Actually, I do have a patch that does that, I might dig it up. The rest looks good: Reviewed-by: Oscar Salvador <osalvador@suse.de> >
On Fri, Apr 26, 2019 at 03:59:12PM +0200, Oscar Salvador wrote: > On Wed, Apr 17, 2019 at 11:39:16AM -0700, Dan Williams wrote: > > @@ -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; > > > > 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; > > > > if (pfn_to_nid(pfn) != nid) > > The last loop from shrink_{pgdat,zone}_span can be reworked to unify both > in one function, and both functions can be factored out a bit. > Actually, I do have a patch that does that, I might dig it up. > > The rest looks good: > > Reviewed-by: Oscar Salvador <osalvador@suse.de> I mean of course besides Ralph's comment.
On Wed, Apr 17, 2019 at 2:53 PM Dan Williams <dan.j.williams@intel.com> 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(-) given removing all unused "*ms" Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
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; 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; 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; 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; if (pfn_to_nid(pfn) != nid)
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(-)