github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftests/mm: skip khugepaged page cache cases without a PMD folio

Browse Source 
The page cache caps folio order at MAX_PAGECACHE_ORDER, which is below the
PMD order on arm64 with 64K pages, where a PMD is 512M.  A PMD-sized page
cache folio is impossible there, so the kernel refuses these collapses:
MADV_COLLAPSE answers -EINVAL and khugepaged passes over the range.  Four
shmem cases ask for a PMD-sized folio anyway, fail, and the run bails out
in the middle.

Skip the shmem and file mem types where the cap is below the PMD order.

The cap is not shmem-specific: it applies to every file folio.  Add
thp_file_supported_orders() to read the orders the page cache allows.

Anonymous collapse is unaffected: its orders are not capped this way.

Link: https://lore.kernel.org/20260919002451.496763-5-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Assisted-by: LLM
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "David Hildenbrand (arm)" <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: kernel-team@meta.com
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache (Red Hat) <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
This commit is contained in:
Kiryl Shutsemau (Meta) 2026-09-19 01:24:34 +01:00 committed by Andrew Morton
parent e8e83ce6f4
commit ceffb8ff83
2 changed files with 28 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
tools/lib/mm/hugepage_settings.h
View File

@ -87,6 +87,15 @@ void thp_set_read_ahead_path(char *path);
unsigned long thp_supported_orders(void);
unsigned long thp_shmem_supported_orders(void);
/*
* The per-order shmem_enabled attribute is created for the orders the page
* cache can hold, not just for shmem, so it answers for regular files too.
*/
static inline unsigned long thp_file_supported_orders(void)
{
return thp_shmem_supported_orders();
}
bool thp_available(void);
bool thp_is_enabled(void);

19
tools/testing/selftests/mm/khugepaged.c
View File

@ -1358,6 +1358,25 @@ int main(int argc, char **argv)
setbuf(stdout, NULL);
/*
* Without a PMD-order page cache folio the kernel refuses these
* collapses, so there is nothing to test.
*/
if (!(thp_file_supported_orders() & (1UL << hpage_pmd_order))) {
if (shmem_ops) {
ksft_print_msg("no PMD-order page cache folio: skipping shmem\n");
shmem_ops = NULL;
}
if (read_only_file_ops) {
ksft_print_msg("no PMD-order page cache folio: skipping file\n");
read_only_file_ops = NULL;
read_write_file_read_ops = NULL;
read_write_file_write_ops = NULL;
}
if (!anon_ops && !shmem_ops && !read_only_file_ops)
ksft_exit_skip("No mem_type left to run\n");
}
default_settings.khugepaged.max_ptes_none = hpage_pmd_nr - 1;
default_settings.khugepaged.max_ptes_swap = hpage_pmd_nr / 8;
default_settings.khugepaged.max_ptes_shared = hpage_pmd_nr / 2;