Re: [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-09 Thread Baoquan He
On 12/09/21 at 02:10pm, David Hildenbrand wrote: .. > >>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c > >>> index c5952749ad40..ac0ea42a4e5f 100644 > >>> --- a/mm/page_alloc.c > >>> +++ b/mm/page_alloc.c > >>> @@ -9459,4 +9459,15 @@ bool take_page_off_buddy(struct page *page) > >>>

Re: [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-09 Thread David Hildenbrand
On 09.12.21 14:02, Baoquan He wrote: > On 12/07/21 at 12:23pm, David Hildenbrand wrote: >> On 07.12.21 04:07, Baoquan He wrote: >>> In some places of the current kernel, it assumes that dma zone must have >>> managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. >>> E.g in

Re: [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-09 Thread Baoquan He
On 12/07/21 at 12:23pm, David Hildenbrand wrote: > On 07.12.21 04:07, Baoquan He wrote: > > In some places of the current kernel, it assumes that dma zone must have > > managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. > > E.g in kdump kernel of x86_64, only low 1M is

Re: [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-07 Thread David Hildenbrand
On 07.12.21 04:07, Baoquan He wrote: > In some places of the current kernel, it assumes that dma zone must have > managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. > E.g in kdump kernel of x86_64, only low 1M is presented and locked down > at very early stage of boot, so

Re: [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-06 Thread John Donnelly
On 12/6/21 9:07 PM, Baoquan He wrote: In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that

[PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists

2021-12-06 Thread Baoquan He
In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that there's no managed pages at all in DMA