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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Li Xinhai <lixinhai.lxh@gmail.com>,
	linux-mm@kvack.org, akpm@linux-foundation.org
Cc: Michal Hocko <mhocko@suse.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: [PATCH v5] mm/mempolicy: Checking hugepage migration is supported by arch in vma_migratable
Date: Fri, 24 Jan 2020 07:42:03 +0530	[thread overview]
Message-ID: <a8ec49f6-03f6-75ca-d3ee-a852206d41f4@arm.com> (raw)
In-Reply-To: <1579786179-30633-1-git-send-email-lixinhai.lxh@gmail.com>

On 01/23/2020 06:59 PM, Li Xinhai wrote:
> vma_migratable() is called to check if pages in vma can be migrated
> before go ahead to further actions. Currently it is used in below code
> path:
> - task_numa_work
> - mbind
> - move_pages
> 
> For hugetlb mapping, whether vma is migratable or not is determined by:
> - CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
> - arch_hugetlb_migration_supported
> 
> Issue: current code only checks for CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
> alone, and  no code should use it directly. (note that current code in
> vma_migratable don't cause failure or bug because
> unmap_and_move_huge_page() will catch unsupported hugepage and handle it
> properly)
> 
> This patch checks the two factors by hugepage_migration_supported for
> impoving code logic and robustness. It will enable early bail out of
> hugepage migration procedure, but because currently all architecture
> supporting hugepage migration is able to support all page size, we would
> not see performance gain with this patch applied.
> 
> vma_migratable() is moved to mm/mempolicy.c, because of the circular
> reference of mempolicy.h and hugetlb.h cause defining it as inline not
> feasible.
> 
> Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>


  parent reply	other threads:[~2020-01-24  2:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-23 13:29 [PATCH v5] mm/mempolicy: Checking hugepage migration is supported by arch in vma_migratable Li Xinhai
2020-01-23 16:56 ` Michal Hocko
2020-01-23 23:24 ` Mike Kravetz
2020-01-24  2:12 ` Anshuman Khandual [this message]
2020-01-24  2:36 ` HORIGUCHI NAOYA(堀口 直也)

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