lkml.org 
[lkml]   [2015]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC 00/16] Introduce ZONE_CMA
On 03/05/2015 05:53 PM, Vlastimil Babka wrote:
> On 02/12/2015 08:32 AM, Joonsoo Kim wrote:
>>
>> 1) Break non-overlapped zone assumption
>> CMA regions could be spread to all memory range, so, to keep all of them
>> into one zone, span of ZONE_CMA would be overlap to other zones'.
>
> From patch 13/16 ut seems to me that indeed the ZONE_CMA spans the area of all
> other zones. This seems very inefficient for e.g. compaction scanners, which
> will repeatedly skip huge amounts of pageblocks that don't belong to ZONE_CMA.
> Could you instead pick only a single zone on a node from which you steal the
> pages? That would allow to keep the span low.
>
> Another disadvantage I see is that to allocate from ZONE_CMA you will have now
> to reclaim enough pages within the zone itself. I think think the cma allocation

I don't think...

> supports migrating pages from ZONE_CMA to the adjacent non-CMA zone, which would
> be equivalent to migration from MIGRATE_CMA pageblocks to the rest of the zone?
>
>> I'm not sure that there is an assumption about possibility of zone overlap
>> But, if ZONE_CMA is introduced, this assumption becomes reality
>> so we should deal with this situation. I investigated most of sites
>> that iterates pfn on certain zone and found that they normally doesn't
>> consider zone overlap. I tried to handle these cases by myself in the
>> early of this series. I hope that there is no more site that depends on
>> non-overlap zone assumption when iterating pfn on certain zone.
>>
>> I passed boot test on x86, ARM32 and ARM64. I did some stress tests
>> on x86 and there is no problem. Feel free to enjoy and please give me
>> a feedback. :)
>>
>> This patchset is based on v3.18.
>>
>> Thanks.
>>
>> [1] https://lkml.org/lkml/2014/5/28/64
>> [2] https://lkml.org/lkml/2014/11/4/55
>> [3] https://lkml.org/lkml/2014/10/15/623
>> [4] https://lkml.org/lkml/2014/5/30/320
>>
>>
>> Joonsoo Kim (16):
>> mm/page_alloc: correct highmem memory statistics
>> mm/writeback: correct dirty page calculation for highmem
>> mm/highmem: make nr_free_highpages() handles all highmem zones by
>> itself
>> mm/vmstat: make node_page_state() handles all zones by itself
>> mm/vmstat: watch out zone range overlap
>> mm/page_alloc: watch out zone range overlap
>> mm/page_isolation: watch out zone range overlap
>> power: watch out zone range overlap
>> mm/cma: introduce cma_total_pages() for future use
>> mm/highmem: remove is_highmem_idx()
>> mm/page_alloc: clean-up free_area_init_core()
>> mm/cma: introduce new zone, ZONE_CMA
>> mm/cma: populate ZONE_CMA and use this zone when GFP_HIGHUSERMOVABLE
>> mm/cma: print stealed page count
>> mm/cma: remove ALLOC_CMA
>> mm/cma: remove MIGRATE_CMA
>>
>> arch/x86/include/asm/sparsemem.h | 2 +-
>> arch/x86/mm/highmem_32.c | 3 +
>> include/linux/cma.h | 9 ++
>> include/linux/gfp.h | 31 +++---
>> include/linux/mempolicy.h | 2 +-
>> include/linux/mm.h | 1 +
>> include/linux/mmzone.h | 58 +++++-----
>> include/linux/page-flags-layout.h | 2 +
>> include/linux/vm_event_item.h | 8 +-
>> include/linux/vmstat.h | 26 +----
>> kernel/power/snapshot.c | 15 +++
>> lib/show_mem.c | 2 +-
>> mm/cma.c | 70 ++++++++++--
>> mm/compaction.c | 6 +-
>> mm/highmem.c | 12 +-
>> mm/hugetlb.c | 2 +-
>> mm/internal.h | 3 +-
>> mm/memory_hotplug.c | 3 +
>> mm/mempolicy.c | 3 +-
>> mm/page-writeback.c | 8 +-
>> mm/page_alloc.c | 223 +++++++++++++++++++++----------------
>> mm/page_isolation.c | 14 ++-
>> mm/vmscan.c | 2 +-
>> mm/vmstat.c | 16 ++-
>> 24 files changed, 317 insertions(+), 204 deletions(-)
>>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>



\
 
 \ /
  Last update: 2015-03-05 19:01    [W:0.163 / U:4.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site