Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-16 Thread Sudarshan Rajagopalan
On 2020-10-15 01:36, Will Deacon wrote: On Wed, Oct 14, 2020 at 05:51:23PM -0700, Sudarshan Rajagopalan wrote: When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB

Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-15 Thread Will Deacon
On Wed, Oct 14, 2020 at 05:51:23PM -0700, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from > physically continuous memory of size PMD_SIZE using > vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB > pressure. But when system is

Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-14 Thread Sudarshan Rajagopalan
On 2020-10-13 04:38, Anshuman Khandual wrote: On 10/13/2020 04:35 AM, Sudarshan Rajagopalan wrote: When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure.

[PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-14 Thread Sudarshan Rajagopalan
When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure. But when system is highly fragmented and memory blocks are being hot-added at runtime, its possible

[PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-14 Thread Sudarshan Rajagopalan
V1: The initial patch used the approach to abort at the first instance of PMD_SIZE allocation failure, unmaps all previously mapped sections using vmemmap_free and maps the entire request with vmemmap_populate_basepages to allocate virtually contiguous memory. https://lkml.org/lkml/2020/9/10/66

Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-13 Thread Anshuman Khandual
On 10/13/2020 04:35 AM, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from physically > continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section > mappings are good to reduce TLB pressure. But when system is highly fragmented >

[PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-12 Thread Sudarshan Rajagopalan
When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure. But when system is highly fragmented and memory blocks are being hot-added at runtime, its possible

[PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-12 Thread Sudarshan Rajagopalan
V1: The initial patch used the approach to abort at the first instance of PMD_SIZE allocation failure, unmaps all previously mapped sections using vmemmap_free and maps the entire request with vmemmap_populate_basepages to allocate virtually contiguous memory. https://lkml.org/lkml/2020/9/10/66

Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-11 Thread Gavin Shan
On 10/6/20 2:36 PM, Anshuman Khandual wrote: On 10/02/2020 01:46 AM, Sudarshan Rajagopalan wrote: When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure.

Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-05 Thread Anshuman Khandual
On 10/02/2020 01:46 AM, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from physically > continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section > mappings are good to reduce TLB pressure. But when system is highly fragmented >

[PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory

2020-10-01 Thread Sudarshan Rajagopalan
When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure. But when system is highly fragmented and memory blocks are being hot-added at runtime, its possible