The quilt patch titled
Subject: include/linux/swapops.h: remove stub for non_swap_entry()
has been removed from the -mm tree. Its filename was
mm-remove-stub-for-non_swap_entry.patch
This patch was dropped because it was merged into mm-stable
------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: include/linux/swapops.h: remove stub for non_swap_entry()
The stub for non_swap_entry() may not help much, because MAX_SWAPFILES has
already contained all the information to decide whether a swap entry is
real swap entry or pesudo ones (migrations, ...).
There can be some performance influences on non_swap_entry() with below
conditions all met:
!CONFIG_MIGRATION && !CONFIG_MEMORY_FAILURE && !CONFIG_DEVICE_PRIVATE
But that's definitely not the major config most machines will use, at the
meantime it's already in a slow path of swap entry (being parsed from a
swap pte), so IMHO it shouldn't be a major issue. Also according to the
analysis from Alistair, somehow the stub didn't do the job right [1].
To make the code cleaner, let's drop the stub.
[1] https://lore.kernel.org/lkml/8735ihbw6g.fsf@nvdebian.thelocal/
Note: the uffd-wp shmem & hugetlbfs series will need this patch to make
sure swap entries work as expected with below config as spotted by
Alistair:
!CONFIG_MIGRATION &&
!CONFIG_MEMORY_FAILURE &&
!CONFIG_DEVICE_PRIVATE &&
CONFIG_PTE_MARKER
(PS: this config should mostly never gonna happen, though, afaict..)
Link: https://lkml.kernel.org/r/20220413191147.66645-1-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swapops.h | 8 --------
1 file changed, 8 deletions(-)
--- a/include/linux/swapops.h~mm-remove-stub-for-non_swap_entry
+++ a/include/linux/swapops.h
@@ -387,18 +387,10 @@ static inline void num_poisoned_pages_in
}
#endif
-#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
- defined(CONFIG_DEVICE_PRIVATE)
static inline int non_swap_entry(swp_entry_t entry)
{
return swp_type(entry) >= MAX_SWAPFILES;
}
-#else
-static inline int non_swap_entry(swp_entry_t entry)
-{
- return 0;
-}
-#endif
#endif /* CONFIG_MMU */
#endif /* _LINUX_SWAPOPS_H */
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-introduce-pte_marker-swap-entry.patch
mm-introduce-pte_marker-swap-entry-fix.patch
mm-teach-core-mm-about-pte-markers.patch
mm-teach-core-mm-about-pte-markers-fix.patch
mm-check-against-orig_pte-for-finish_fault.patch
mm-check-against-orig_pte-for-finish_fault-fix.patch
mm-uffd-pte_marker_uffd_wp.patch
mm-uffd-pte_marker_uffd_wp-fix.patch
mm-shmem-take-care-of-uffdio_copy_mode_wp.patch
mm-shmem-handle-uffd-wp-special-pte-in-page-fault-handler.patch
mm-shmem-persist-uffd-wp-bit-across-zapping-for-file-backed.patch
mm-shmem-allow-uffd-wr-protect-none-pte-for-file-backed-mem.patch
mm-shmem-allows-file-back-mem-to-be-uffd-wr-protected-on-thps.patch
mm-shmem-handle-uffd-wp-during-fork.patch
mm-hugetlb-introduce-huge-pte-version-of-uffd-wp-helpers.patch
mm-hugetlb-hook-page-faults-for-uffd-write-protection.patch
mm-hugetlb-take-care-of-uffdio_copy_mode_wp.patch
mm-hugetlb-handle-uffdio_writeprotect.patch
mm-hugetlb-handle-pte-markers-in-page-faults.patch
mm-hugetlb-allow-uffd-wr-protect-none-ptes.patch
mm-hugetlb-only-drop-uffd-wp-special-pte-if-required.patch
mm-hugetlb-only-drop-uffd-wp-special-pte-if-required-fix.patch
mm-hugetlb-handle-uffd-wp-during-fork.patch
mm-khugepaged-dont-recycle-vma-pgtable-if-uffd-wp-registered.patch
mm-pagemap-recognize-uffd-wp-bit-for-shmem-hugetlbfs.patch
mm-uffd-enable-write-protection-for-shmem-hugetlbfs.patch
mm-enable-pte-markers-by-default.patch
mm-enable-pte-markers-by-default-fix.patch
selftests-uffd-enable-uffd-wp-for-shmem-hugetlbfs.patch
mm-uffd-move-userfaultfd-configs-into-mm.patch
