From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: huge tmpfs: remove shrinklist addition from shmem_setattr() There's a block of code in shmem_setattr() to add the inode to shmem_unused_huge_shrink()'s shrinklist when lowering i_size: it dates from before 5.7 changed truncation to do split_huge_page() for itself, and should have been removed at that time. I am over-stating that: split_huge_page() can fail (notably if there's an extra reference to the page at that time), so there might be value in retrying. But there were already retries as truncation worked through the tails, and this addition risks repeating unsuccessful retries indefinitely: I'd rather remove it now, and work on reducing the chance of split_huge_page() failures separately, if we need to. Link: https://lkml.kernel.org/r/b73b3492-8822-18f9-83e2-938528cdde94@xxxxxxxxxx Fixes: 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page() when punching hole") Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Reviewed-by: Yang Shi <shy828301@xxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 19 ------------------- 1 file changed, 19 deletions(-) --- a/mm/shmem.c~huge-tmpfs-remove-shrinklist-addition-from-shmem_setattr +++ a/mm/shmem.c @@ -1058,7 +1058,6 @@ static int shmem_setattr(struct user_nam { struct inode *inode = d_inode(dentry); struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); int error; error = setattr_prepare(&init_user_ns, dentry, attr); @@ -1094,24 +1093,6 @@ static int shmem_setattr(struct user_nam if (oldsize > holebegin) unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); - - /* - * Part of the huge page can be beyond i_size: subject - * to shrink under memory pressure. - */ - if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { - spin_lock(&sbinfo->shrinklist_lock); - /* - * _careful to defend against unlocked access to - * ->shrink_list in shmem_unused_huge_shrink() - */ - if (list_empty_careful(&info->shrinklist)) { - list_add_tail(&info->shrinklist, - &sbinfo->shrinklist); - sbinfo->shrinklist_len++; - } - spin_unlock(&sbinfo->shrinklist_lock); - } } } _
