On Wed, Dec 29, 2021 at 11:36:49AM +0800, Chen Wandun wrote:
> There is no need to try to move_freepages_block for pages that is not
> in buddy in function unset_migratetype_isolate, it can directly set
> migrate type.
The above could benefit from some rephrasing, someting along these lines
maybe?
"In unset_migratetype_isolate(), we can bypass the call to
move_freepages_block() for non-buddy pages"
>
> It will save a few cpu cycles for some situations such as cma and
> hugetlb when allocating continue pages, in these situation function
> alloc_contig_pages will be called.
>
> alloc_contig_pages
> __alloc_contig_migrate_range
> isolate_freepages_range ==> pages has been remove from buddy
> undo_isolate_page_range
> unset_migratetype_isolate ==> can directly set migratetype
>
> Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
> Signed-off-by: Chen Wandun <chenwandun@xxxxxxxxxx>
I am ok with the "fix", but I don't think this deserves a Fixes tag.
Sure, it can spare some cpu cycles, but besides that, there is no harm
in the actual code unless I missed something.
Others might feel stronger about that.
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
--
Oscar Salvador
SUSE Labs
