> On Jun 21, 2019, at 8:11 PM, Hillf Danton <hdanton@xxxxxxxx> wrote:
>
>
> Hello
>
> On Fri, 21 Jun 2019 17:05:10 -0700 Song Liu <songliubraving@xxxxxx> wrote:
>> Next patch will add khugepaged support of non-shmem files. This patch
>> renames these two functions to reflect the new functionality:
>>
>> collapse_shmem() => collapse_file()
>> khugepaged_scan_shmem() => khugepaged_scan_file()
>>
>> Acked-by: Rik van Riel <riel@xxxxxxxxxxx>
>> Signed-off-by: Song Liu <songliubraving@xxxxxx>
>> ---
>> mm/khugepaged.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>> index 0f7419938008..dde8e45552b3 100644
>> --- a/mm/khugepaged.c
>> +++ b/mm/khugepaged.c
>> @@ -1287,7 +1287,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
>> }
>>
>> /**
>> - * collapse_shmem - collapse small tmpfs/shmem pages into huge one.
>> + * collapse_file - collapse small tmpfs/shmem pages into huge one.
>> *
>> * Basic scheme is simple, details are more complex:
>> * - allocate and lock a new huge page;
>> @@ -1304,10 +1304,11 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
>> * + restore gaps in the page cache;
>> * + unlock and free huge page;
>> */
>> -static void collapse_shmem(struct mm_struct *mm,
>> +static void collapse_file(struct vm_area_struct *vma,
>> struct address_space *mapping, pgoff_t start,
>> struct page **hpage, int node)
>> {
>> + struct mm_struct *mm = vma->vm_mm;
>> gfp_t gfp;
>> struct page *new_page;
>> struct mem_cgroup *memcg;
>> @@ -1563,7 +1564,7 @@ static void collapse_shmem(struct mm_struct *mm,
>> /* TODO: tracepoints */
>> }
>>
>> -static void khugepaged_scan_shmem(struct mm_struct *mm,
>> +static void khugepaged_scan_file(struct vm_area_struct *vma,
>> struct address_space *mapping,
>> pgoff_t start, struct page **hpage)
>> {
>> @@ -1631,14 +1632,14 @@ static void khugepaged_scan_shmem(struct mm_struct *mm,
>> result = SCAN_EXCEED_NONE_PTE;
>> } else {
>> node = khugepaged_find_target_node();
>> - collapse_shmem(mm, mapping, start, hpage, node);
>> + collapse_file(vma, mapping, start, hpage, node);
>> }
>> }
>>
>> /* TODO: tracepoints */
>> }
>> #else
>> -static void khugepaged_scan_shmem(struct mm_struct *mm,
>> +static void khugepaged_scan_file(struct vm_area_struct *vma,
>> struct address_space *mapping,
>> pgoff_t start, struct page **hpage)
>> {
>> @@ -1722,7 +1723,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
>> file = get_file(vma->vm_file);
>> up_read(&mm->mmap_sem);
>> ret = 1;
>> - khugepaged_scan_shmem(mm, file->f_mapping,
>> + khugepaged_scan_file(vma, file->f_mapping,
>> pgoff, hpage);
>> fput(file);
>
> Is it a change that should have put some material in the log message?
> Is it unlikely for vma to go without mmap_sem held?
This is a great point. We really need to be more careful. Let me fix
it in the next version.
Thanks,
Song
