Re: [RFC PATCH 00/12] mm: mirrored memory support for page buddy allocations
From: Vlastimil Babka
Date: Tue Jun 16 2015 - 03:53:54 EST
On 06/04/2015 02:54 PM, Xishi Qiu wrote:
> Intel Xeon processor E7 v3 product family-based platforms introduces support
> for partial memory mirroring called as 'Address Range Mirroring'. This feature
> allows BIOS to specify a subset of total available memory to be mirrored (and
> optionally also specify whether to mirror the range 0-4 GB). This capability
> allows user to make an appropriate tradeoff between non-mirrored memory range
> and mirrored memory range thus optimizing total available memory and still
> achieving highly reliable memory range for mission critical workloads and/or
> kernel space.
> Tony has already send a patchset to supprot this feature at boot time.
> This patchset can support the feature after boot time. It introduces mirror_info
> to save the mirrored memory range. Then use __GFP_MIRROR to allocate mirrored
> I think add a new migratetype is btter and easier than a new zone, so I use
If the mirrored memory is in a single reasonably compact (no large holes) range
(per NUMA node) and won't dynamically change its size, then zone might be a
better option. For one thing, it will still allow distinguishing movable and
unmovable allocations within the mirrored memory.
We had enough fun with MIGRATE_CMA and all kinds of checks it added to allocator
hot paths, and even CMA is now considering moving to a separate zone.
> MIGRATE_MIRROR to manage the mirrored pages. However it changed some code in the
> core file, please review and comment, thanks.
> 1) call add_mirror_info() to fill mirrored memory info.
> 2) add compatibility with memory online/offline.
> 3) add more interface? others?
> Xishi Qiu (12):
> mm: add a new config to manage the code
> mm: introduce mirror_info
> mm: introduce MIGRATE_MIRROR to manage the mirrored pages
> mm: add mirrored pages to buddy system
> mm: introduce a new zone_stat_item NR_FREE_MIRROR_PAGES
> mm: add free mirrored pages info
> mm: introduce __GFP_MIRROR to allocate mirrored pages
> mm: use mirrorable to switch allocate mirrored memory
> mm: enable allocate mirrored memory at boot time
> mm: add the buddy system interface
> mm: add the PCP interface
> mm: let slab/slub/slob use mirrored memory
> arch/x86/mm/numa.c | 3 ++
> drivers/base/node.c | 17 ++++---
> fs/proc/meminfo.c | 6 +++
> include/linux/gfp.h | 5 +-
> include/linux/mmzone.h | 23 +++++++++
> include/linux/vmstat.h | 2 +
> kernel/sysctl.c | 9 ++++
> mm/Kconfig | 8 +++
> mm/page_alloc.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++---
> mm/slab.c | 3 +-
> mm/slob.c | 2 +-
> mm/slub.c | 2 +-
> mm/vmstat.c | 4 ++
> 13 files changed, 202 insertions(+), 16 deletions(-)
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