From 8d9ef5a7386dbf5fa3df476060ecdc9197313d10 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 23 May 2022 21:18:32 +0800 Subject: [PATCH] huge tmpfs: remove shrinklist addition from shmem_setattr() mainline inclusion from mainline-v5.15 commit 2b5bbcb1c9c2cd05a06dcf54df77255a8c406a7b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I58GJ0 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b5bbcb1c9c2cd05a06dcf54df77255a8c406a7b -------------------------------- 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@google.com Fixes: 71725ed10c40 ("mm: huge tmpfs: try to split_huge_page() when punching hole") Signed-off-by: Hugh Dickins Reviewed-by: Yang Shi Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Kravetz Cc: Rik van Riel Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds conflicts: mm/shmem.c Signed-off-by: Chen Wandun Reviewed-by: Kefeng Wang Signed-off-by: Zheng Zengkai --- mm/shmem.c | 19 ------------------- 1 file changed, 19 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index c45606bd8434..9df016296347 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1093,7 +1093,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) { 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(dentry, attr); @@ -1129,24 +1128,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) 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); - } } } -- GitLab