Messages in this thread | | | Date | Fri, 26 Jun 2015 08:54:35 +0900 | From | Kamezawa Hiroyuki <> | Subject | Re: [RFC PATCH 10/12] mm: add the buddy system interface |
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On 2015/06/25 18:44, Xishi Qiu wrote: > On 2015/6/10 11:06, Kamezawa Hiroyuki wrote: > >> On 2015/06/09 19:04, Xishi Qiu wrote: >>> On 2015/6/9 15:12, Kamezawa Hiroyuki wrote: >>> >>>> On 2015/06/04 22:04, Xishi Qiu wrote: >>>>> Add the buddy system interface for address range mirroring feature. >>>>> Allocate mirrored pages in MIGRATE_MIRROR list. If there is no mirrored pages >>>>> left, use other types pages. >>>>> >>>>> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> >>>>> --- >>>>> mm/page_alloc.c | 40 +++++++++++++++++++++++++++++++++++++++- >>>>> 1 file changed, 39 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>>>> index d4d2066..0fb55288 100644 >>>>> --- a/mm/page_alloc.c >>>>> +++ b/mm/page_alloc.c >>>>> @@ -599,6 +599,26 @@ static inline bool is_mirror_pfn(unsigned long pfn) >>>>> >>>>> return false; >>>>> } >>>>> + >>>>> +static inline bool change_to_mirror(gfp_t gfp_flags, int high_zoneidx) >>>>> +{ >>>>> + /* >>>>> + * Do not alloc mirrored memory below 4G, because 0-4G is >>>>> + * all mirrored by default, and the list is always empty. >>>>> + */ >>>>> + if (high_zoneidx < ZONE_NORMAL) >>>>> + return false; >>>>> + >>>>> + /* Alloc mirrored memory for only kernel */ >>>>> + if (gfp_flags & __GFP_MIRROR) >>>>> + return true; >>>> >>>> GFP_KERNEL itself should imply mirror, I think. >>>> >>> >>> Hi Kame, >>> >>> How about like this: #define GFP_KERNEL (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_MIRROR) ? >>> >> >> Hm.... it cannot cover GFP_ATOMIC at el. >> >> I guess, mirrored memory should be allocated if !__GFP_HIGHMEM or !__GFP_MOVABLE > > > Hi Kame, > > Can we distinguish allocations form user or kernel only by GFP flags? >
Allocation from user and file caches are now *always* done with __GFP_MOVABLE.
By this, pages will be allocated from MIGRATE_MOVABLE migration type. MOVABLE migration type means it's can be the target for page compaction or memory-hot-remove.
Thanks, -Kame
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