On 2 Sep 2024, at 12:42, David Hildenbrand wrote:
> On 02.09.24 17:34, Zi Yan wrote:
>> On 2 Sep 2024, at 5:06, David Hildenbrand wrote:
>>
>>> On 28.08.24 22:22, Zi Yan wrote:
>>>> migratetype is no longer overwritten during pageblock isolation,
>>>> start_isolate_page_range(), has_unmovable_pages(), and
>>>> set_migratetype_isolate() no longer need which migratetype to restore
>>>> during isolation failure. For has_unmoable_pages(), it needs to know if
>>>> the isolation is for CMA allocation, so adding CMA_ALLOCATION to isolation
>>>> flags to provide the information.
>>>>
>>>> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
>>>> ---
>>>> include/linux/page-isolation.h | 3 ++-
>>>> mm/memory_hotplug.c | 1 -
>>>> mm/page_alloc.c | 4 +++-
>>>> mm/page_isolation.c | 27 +++++++++++----------------
>>>> 4 files changed, 16 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
>>>> index c2a1bd621561..e94117101b6c 100644
>>>> --- a/include/linux/page-isolation.h
>>>> +++ b/include/linux/page-isolation.h
>>>> @@ -32,13 +32,14 @@ static inline bool is_migrate_isolate(int migratetype)
>>>> #define MEMORY_OFFLINE 0x1
>>>> #define REPORT_FAILURE 0x2
>>>> +#define CMA_ALLOCATION 0x4
>>>> void set_pageblock_migratetype(struct page *page, int migratetype);
>>>> bool move_freepages_block_isolate(struct zone *zone, struct page *page);
>>>> int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>>>> - int migratetype, int flags, gfp_t gfp_flags);
>>>> + int flags, gfp_t gfp_flags);
>>>> void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
>>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>>> index 4265272faf4c..fe0b71e0f307 100644
>>>> --- a/mm/memory_hotplug.c
>>>> +++ b/mm/memory_hotplug.c
>>>> @@ -1993,7 +1993,6 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
>>>> /* set above range as isolated */
>>>> ret = start_isolate_page_range(start_pfn, end_pfn,
>>>> - MIGRATE_MOVABLE,
>>>> MEMORY_OFFLINE | REPORT_FAILURE,
>>>> GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
>>>> if (ret) {
>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>> index 4d06932ba69a..c60bb95d7e65 100644
>>>> --- a/mm/page_alloc.c
>>>> +++ b/mm/page_alloc.c
>>>> @@ -6607,7 +6607,9 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
>>>> * put back to page allocator so that buddy can use them.
>>>> */
>>>> - ret = start_isolate_page_range(start, end, migratetype, 0, gfp_mask);
>>>> + ret = start_isolate_page_range(start, end,
>>>> + migratetype == MIGRATE_CMA ? CMA_ALLOCATION : 0,
>>>
>>> Can we have flags for alloc_contig_range() instead of passing in a (weird) migratetype?
>>>
>>> Then, we should make sure that we warn if we try a CMA allocation on any pageblock that is not of type CMA.
>>
>> Sure. I will expose the existing isolation flags (MEMORY_OFFLINE, REPORT_FAILURE,
>> and CMA_ALLOCATION) as alloc_contig_range() parameter to replace migratetype one.
>>
>
> Maybe we want some proper, distinct alloc_contig_range() falgs "acr_flags_t". Might be cleanest, to express anything that doesn't fall into the gfp_t flag category.
>
> Exposing MEMORY_OFFLINE feels wrong, for example.
OK, it seems that I mixed up of start_isolate_page_range() flags with
alloc_contig_range() flags. Let me clarify them below.
For start_isolate_page_range(), memory offline calls it separately and
needs MEMORY_OFFLINE and REPORT_FAILURE; CMA allocation uses it via
alloc_contig_range() and needs a flag (like CMA_ALLOCATION) for its
own checks.
BTW, it seems to me that MEMORY_OFFLINE and REPORT_FAILURE can be merged,
since they are always used together. Let me know if you disagree.
For alloc_contig_range(), migratetype parameter is what you are talking about
above. There are two callers: cma_alloc() and alloc_contig_pages().
The acr_flags_t is basically a caller id. Something like?
enum acr_flags_t {
ACR_CMA_ALLOC,
ACR_CONTIG_PAGES,
};
And ACR_CMA_ALLOC needs to be translated to CMA_ALLOCATION when
start_isolate_page_range() is called.
BTW, after removing migratetype parameter from alloc_contig_range(),
the tracepoint in __alloc_contig_migrate_range() needs to be changed to
use acr_flags_t, since I do not think we want to convert acr_flags_t
back to migratetype.
Best Regards,
Yan, Zi
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