Re: [PATCH v9 03/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal
On Mon, Jun 17, 2019 at 6:42 PM Wei Yang wrote:
>
> 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.
I don't see a problem.
Re: [PATCH v9 03/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal
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-nvd...@lists.01.org
>https://lists.01.org/mailman/listinfo/linux-nvdimm
--
Wei Yang
Help you, Help me
[PATCH v9 03/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal
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;
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)
