Ning Qu wrote:
> When comes to truncate file, add support to handle huge page in the
> truncate range.
>
> Signed-off-by: Ning Qu <quning@xxxxxxxxx>
> ---
> mm/shmem.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 86 insertions(+), 11 deletions(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 0a423a9..90f2e0e 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -559,6 +559,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
> struct shmem_inode_info *info = SHMEM_I(inode);
> pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
> pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT;
> + /* Whether we have to do partial truncate */
> unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1);
> unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1);
> struct pagevec pvec;
> @@ -570,12 +571,16 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
> if (lend == -1)
> end = -1; /* unsigned, so actually very big */
>
> + i_split_down_read(inode);
> pagevec_init(&pvec, 0);
> index = start;
> while (index < end) {
> + bool thp = false;
> +
> pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
> min(end - index, (pgoff_t)PAGEVEC_SIZE),
> pvec.pages, indices);
> +
> if (!pvec.nr)
> break;
> mem_cgroup_uncharge_start();
> @@ -586,6 +591,25 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
> if (index >= end)
> break;
>
> + thp = PageTransHugeCache(page);
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE
Again. Here and below ifdef is redundant: PageTransHugeCache() is zero
compile-time and thp case will be optimize out.
And do we really need a copy of truncate logic here? Is there a way to
share code?
--
Kirill A. Shutemov
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