Re: [PATCH v2 3/5] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions

2021-01-12 Thread Oscar Salvador
On Tue, Jan 12, 2021 at 01:34:53AM -0800, Dan Williams wrote: > While pfn_to_online_page() is able to determine pfn_valid() at > subsection granularity it is not able to reliably determine if a given > pfn is also online if the section is mixes ZONE_{NORMAL,MOVABLE} with > ZONE_DEVICE. This means t

Re: [PATCH v2 3/5] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions

2021-01-12 Thread David Hildenbrand
On 12.01.21 10:34, Dan Williams wrote: > While pfn_to_online_page() is able to determine pfn_valid() at > subsection granularity it is not able to reliably determine if a given > pfn is also online if the section is mixes ZONE_{NORMAL,MOVABLE} with > ZONE_DEVICE. This means that pfn_to_online_page(

[PATCH v2 3/5] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions

2021-01-12 Thread Dan Williams
While pfn_to_online_page() is able to determine pfn_valid() at subsection granularity it is not able to reliably determine if a given pfn is also online if the section is mixes ZONE_{NORMAL,MOVABLE} with ZONE_DEVICE. This means that pfn_to_online_page() may return invalid @page objects. For example