Messages in this thread | | | Subject | Re: [PATCH v3 7/7] mm, page_alloc: disable pcplists during memory offline | From | David Hildenbrand <> | Date | Thu, 12 Nov 2020 17:09:07 +0100 |
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On 12.11.20 16:18, Vlastimil Babka wrote: > On 11/11/20 6:58 PM, David Hildenbrand wrote: >> On 11.11.20 10:28, Vlastimil Babka wrote: >>> - /* >>> - * per-cpu pages are drained after start_isolate_page_range, but >>> - * if there are still pages that are not free, make sure that we >>> - * drain again, because when we isolated range we might have >>> - * raced with another thread that was adding pages to pcp list. >>> - * >>> - * Forward progress should be still guaranteed because >>> - * pages on the pcp list can only belong to MOVABLE_ZONE >>> - * because has_unmovable_pages explicitly checks for >>> - * PageBuddy on freed pages on other zones. >>> - */ >>> ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); >>> - if (ret) >>> - drain_all_pages(zone); >>> + >> >> Why two empty lines before the "} while (ret);" ? (unless I'm confused >> while looking at this diff) >> > > No there's just a single emply line after "ret = test_pages_isolated..." > Before there was none, which looked ok with the extra identation of the > now-removed "drain_all_pages(zone);" > >>> +void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high, >>> + unsigned long batch) >>> +{ >>> + struct per_cpu_pageset *p; >>> + int cpu; >>> + >>> + for_each_possible_cpu(cpu) { >>> + p = per_cpu_ptr(zone->pageset, cpu); >>> + pageset_update(&p->pcp, high, batch); >>> + } >>> +} >>> + >>> /* >>> * Calculate and set new high and batch values for all per-cpu pagesets of a >>> * zone, based on the zone's size and the percpu_pagelist_fraction sysctl. >>> @@ -6315,8 +6338,6 @@ static void pageset_init(struct per_cpu_pageset *p) >>> static void zone_set_pageset_high_and_batch(struct zone *zone) >>> { >>> unsigned long new_high, new_batch; >>> - struct per_cpu_pageset *p; >>> - int cpu; >>> >>> if (percpu_pagelist_fraction) { >>> new_high = zone_managed_pages(zone) / percpu_pagelist_fraction; >>> @@ -6336,10 +6357,7 @@ static void zone_set_pageset_high_and_batch(struct zone *zone) >>> zone->pageset_high = new_high; >>> zone->pageset_batch = new_batch; >>> >>> - for_each_possible_cpu(cpu) { >>> - p = per_cpu_ptr(zone->pageset, cpu); >>> - pageset_update(&p->pcp, new_high, new_batch); >>> - } >>> + __zone_set_pageset_high_and_batch(zone, new_high, new_batch); >>> } >> >> These two hunks look like an unrelated cleanup, or am I missing something? > > It's extracting part of functionality to __zone_set_pageset_high_and_batch() > that's now called also from zone_pcp_enable() and zone_pcp_disable() - to only > adjust the per-cpu zone->pageset values without the usual calculation. > >> Thanks for looking into this! > > Thanks for review. Here's updated version that adds more detailed comment about > force_all_cpus parameter to __drain_all_pages() header, hopefully that clarifies > your concerns.
LGTM!
Reviewed-by: David Hildenbrand <david@redhat.com>
-- Thanks,
David / dhildenb
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