Messages in this thread | | | Date | Tue, 08 Aug 2017 14:34:25 +0800 | From | Wei Wang <> | Subject | Re: [virtio-dev] Re: [PATCH v13 4/5] mm: support reporting free page blocks |
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On 08/08/2017 02:12 PM, Wei Wang wrote: > On 08/03/2017 05:11 PM, Michal Hocko wrote: >> On Thu 03-08-17 14:38:18, Wei Wang wrote: >> This is just too ugly and wrong actually. Never provide struct page >> pointers outside of the zone->lock. What I've had in mind was to simply >> walk free lists of the suitable order and call the callback for each >> one. >> Something as simple as >> >> for (i = 0; i < MAX_NR_ZONES; i++) { >> struct zone *zone = &pgdat->node_zones[i]; >> >> if (!populated_zone(zone)) >> continue; > > Can we directly use for_each_populated_zone(zone) here? > > >> spin_lock_irqsave(&zone->lock, flags); >> for (order = min_order; order < MAX_ORDER; ++order) { > > > This appears to be covered by for_each_migratetype_order(order, mt) > below. > > >> struct free_area *free_area = &zone->free_area[order]; >> enum migratetype mt; >> struct page *page; >> >> if (!free_area->nr_pages) >> continue; >> >> for_each_migratetype_order(order, mt) { >> list_for_each_entry(page, >> &free_area->free_list[mt], lru) { >> >> pfn = page_to_pfn(page); >> visit(opaque2, prn, 1<<order); >> } >> } >> } >> >> spin_unlock_irqrestore(&zone->lock, flags); >> } >> >> [...] >> > > What do you think if we further simply the above implementation like > this: > > for_each_populated_zone(zone) { > for_each_migratetype_order_decend(1, order, mt) {
here it will be min_order (passed by the caller), instead of "1", that is, for_each_migratetype_order_decend(min_order, order, mt)
> spin_lock_irqsave(&zone->lock, flags); > list_for_each_entry(page, > &zone->free_area[order].free_list[mt], lru) { > pfn = page_to_pfn(page); > visit(opaque1, pfn, 1 << order); > } > spin_unlock_irqrestore(&zone->lock, flags); > } > } > >
Best, Wei
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