The patch titled
Subject: mm/readahead: limit page cache size in page_cache_ra_order()
has been added to the -mm mm-unstable branch. Its filename is
mm-readahead-limit-page-cache-size-in-page_cache_ra_order.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-readahead-limit-page-cache-size-in-page_cache_ra_order.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Gavin Shan <gshan@xxxxxxxxxx>
Subject: mm/readahead: limit page cache size in page_cache_ra_order()
Date: Tue, 25 Jun 2024 19:06:45 +1000
In page_cache_ra_order(), the maximal order of the page cache to be
allocated shouldn't be larger than MAX_PAGECACHE_ORDER. Otherwise, it's
possible the large page cache can't be supported by xarray when the
corresponding xarray entry is split.
For example, HPAGE_PMD_ORDER is 13 on ARM64 when the base page size is
64KB. The PMD-sized page cache can't be supported by xarray.
Link: https://lkml.kernel.org/r/20240625090646.1194644-4-gshan@xxxxxxxxxx
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Zhenyu Zhang <zhenyzha@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/readahead.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/readahead.c~mm-readahead-limit-page-cache-size-in-page_cache_ra_order
+++ a/mm/readahead.c
@@ -449,11 +449,11 @@ void page_cache_ra_order(struct readahea
limit = min(limit, index + ra->size - 1);
- if (new_order < MAX_PAGECACHE_ORDER) {
+ if (new_order < MAX_PAGECACHE_ORDER)
new_order += 2;
- new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order);
- new_order = min_t(unsigned int, new_order, ilog2(ra->size));
- }
+
+ new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order);
+ new_order = min_t(unsigned int, new_order, ilog2(ra->size));
/* See comment in page_cache_ra_unbounded() */
nofs = memalloc_nofs_save();
_
Patches currently in -mm which might be from gshan@xxxxxxxxxx are
mm-filemap-make-max_pagecache_order-acceptable-to-xarray.patch
mm-filemap-skip-to-allocate-pmd-sized-folios-if-needed.patch
mm-readahead-limit-page-cache-size-in-page_cache_ra_order.patch
mm-shmem-disable-pmd-sized-page-cache-if-needed.patch
