linux-kernel - Re: [PATCH] mm: move mask update out of the atomic context

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Message-ID: <f5c7ed26-b034-4600-ba29-26761eb1eef5@arm.com>
Date: Mon, 23 Jun 2025 15:39:13 +0530
From: Dev Jain <dev.jain@....com>
To: Alexander Gordeev <agordeev@...ux.ibm.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: move mask update out of the atomic context


On 23/06/25 3:07 pm, Alexander Gordeev wrote:
> On Mon, Jun 23, 2025 at 02:26:29PM +0530, Dev Jain wrote:
>> On 23/06/25 1:34 pm, Alexander Gordeev wrote:
>>> There is not need to modify page table synchronization mask
>>> while apply_to_pte_range() holds user page tables spinlock.
>> I don't get you, what is the problem with the current code?
>> Are you just concerned about the duration of holding the
>> lock?
> Yes.

Doesn't really matter but still a correct change:

Reviewed-by: Dev Jain <dev.jain@....com>

>
>>> Signed-off-by: Alexander Gordeev <agordeev@...ux.ibm.com>
>>> ---
>>>    mm/memory.c | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/mm/memory.c b/mm/memory.c
>>> index 8eba595056fe..6849ab4e44bf 100644
>>> --- a/mm/memory.c
>>> +++ b/mm/memory.c
>>> @@ -3035,12 +3035,13 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
>>>    			}
>>>    		} while (pte++, addr += PAGE_SIZE, addr != end);
>>>    	}
>>> -	*mask |= PGTBL_PTE_MODIFIED;
>>>    	arch_leave_lazy_mmu_mode();
>>>    	if (mm != &init_mm)
>>>    		pte_unmap_unlock(mapped_pte, ptl);
>>> +	*mask |= PGTBL_PTE_MODIFIED;
>>> +
>>>    	return err;
>>>    }