Commit 6ac04fc4 authored by Hugh Dickins's avatar Hugh Dickins Committed by Euler
Browse files

mm: shmem: extend shmem_unused_huge_shrink() to all sizes 

mainline inclusion
from mainline-v6.12-rc1
commit 15444054a537aca115bb077a77e99a9cc5ae11e6
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBGFBA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=15444054a537aca115bb077a77e99a9cc5ae11e6

--------------------------------

Although shmem_get_folio_gfp() is correctly putting inodes on the
shrinklist according to the folio size, shmem_unused_huge_shrink() was
still dealing with that shrinklist in terms of HPAGE_PMD_SIZE.

Generalize that; and to handle the mixture of sizes more sensibly,
shmem_alloc_and_add_folio() give it a number of pages to be freed
(approximate: no need to minimize that with an exact calculation) instead
of a number of inodes to split.

[akpm@linux-foundation.org: comment tweak, per David]
Link: https://lkml.kernel.org/r/d8c40850-6774-7a93-1e2c-8d941683b260@google.com


Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarWang Lian <dev01404@linx-info.com>
---
parent bf5cb2bf

mm/shmem.c

+20 −25
Original line number Diff line number Diff line
@@ -632,15 +632,14 @@ static const char *shmem_format_huge(int huge) 
#endif



static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,

		struct shrink_control *sc, unsigned long nr_to_split)

		struct shrink_control *sc, unsigned long nr_to_free)

{

	LIST_HEAD(list), *pos, *next;

	LIST_HEAD(to_remove);

	struct inode *inode;

	struct shmem_inode_info *info;

	struct folio *folio;

	unsigned long batch = sc ? sc->nr_to_scan : 128;

	int split = 0;

	unsigned long split = 0, freed = 0;



	if (list_empty(&sbinfo->shrinklist))

		return SHRINK_STOP;
@@ -658,13 +657,6 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, 
			goto next;

		}



		/* Check if there's anything to gain */

		if (round_up(inode->i_size, PAGE_SIZE) ==

				round_up(inode->i_size, HPAGE_PMD_SIZE)) {

			list_move(&info->shrinklist, &to_remove);

			goto next;

		}



		list_move(&info->shrinklist, &list);

next:

		sbinfo->shrinklist_len--;
@@ -673,34 +665,36 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, 
	}

	spin_unlock(&sbinfo->shrinklist_lock);



	list_for_each_safe(pos, next, &to_remove) {

		info = list_entry(pos, struct shmem_inode_info, shrinklist);

		inode = &info->vfs_inode;

		list_del_init(&info->shrinklist);

		iput(inode);

	}



	list_for_each_safe(pos, next, &list) {

		pgoff_t next, end;

		loff_t i_size;

		int ret;

		pgoff_t index;



		info = list_entry(pos, struct shmem_inode_info, shrinklist);

		inode = &info->vfs_inode;



		if (nr_to_split && split >= nr_to_split)

		if (nr_to_free && freed >= nr_to_free)

			goto move_back;



		index = (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT;

		folio = filemap_get_folio(inode->i_mapping, index);

		if (IS_ERR(folio))

		i_size = i_size_read(inode);

		folio = filemap_get_entry(inode->i_mapping, i_size / PAGE_SIZE);

		if (!folio || xa_is_value(folio))

			goto drop;



		/* No huge page at the end of the file: nothing to split */

		/* No large folio at the end of the file: nothing to split */

		if (!folio_test_large(folio)) {

			folio_put(folio);

			goto drop;

		}



		/* Check if there is anything to gain from splitting */

		next = folio_next_index(folio);

		end = shmem_fallocend(inode, DIV_ROUND_UP(i_size, PAGE_SIZE));

		if (end <= folio->index || end >= next) {

			folio_put(folio);

			goto drop;

		}



		/*

		 * Move the inode on the list back to shrinklist if we failed

		 * to lock the page at this time.
@@ -721,6 +715,7 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, 
		if (ret)

			goto move_back;



		freed += next - end;

		split++;

drop:

		list_del_init(&info->shrinklist);
@@ -765,7 +760,7 @@ static long shmem_unused_huge_count(struct super_block *sb, 
#define shmem_huge SHMEM_HUGE_DENY



static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,

		struct shrink_control *sc, unsigned long nr_to_split)

		struct shrink_control *sc, unsigned long nr_to_free)

{

	return 0;

}
@@ -1870,7 +1865,7 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, 
		 * Try to reclaim some space by splitting a few

		 * large folios beyond i_size on the filesystem.

		 */

		shmem_unused_huge_shrink(sbinfo, NULL, 2);

		shmem_unused_huge_shrink(sbinfo, NULL, pages);

		/*

		 * And do a shmem_recalc_inode() to account for freed pages:

		 * except our folio is there in cache, so not quite balanced.