The patch titled
Subject: mm: use single SWP_DEVICE_EXCLUSIVE entry type
has been added to the -mm mm-unstable branch. Its filename is
mm-use-single-swp_device_exclusive-entry-type.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-use-single-swp_device_exclusive-entry-type.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm: use single SWP_DEVICE_EXCLUSIVE entry type
Date: Mon, 10 Feb 2025 20:37:48 +0100
There is no need for the distinction anymore; let's merge the readable and
writable device-exclusive entries into a single device-exclusive entry
type.
Link: https://lkml.kernel.org/r/20250210193801.781278-7-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Simona Vetter <simona.vetter@xxxxxxxx>
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Alex Shi <alexs@xxxxxxxxxx>
Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Karol Herbst <kherbst@xxxxxxxxxx>
Cc: Liam Howlett <liam.howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Lyude <lyude@xxxxxxxxxx>
Cc: "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yanteng Si <si.yanteng@xxxxxxxxx>
Cc: Barry Song <v-songbaohua@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swap.h | 7 +++----
include/linux/swapops.h | 27 ++++-----------------------
mm/mprotect.c | 8 --------
mm/page_table_check.c | 5 ++---
mm/rmap.c | 2 +-
5 files changed, 10 insertions(+), 39 deletions(-)
--- a/include/linux/swap.h~mm-use-single-swp_device_exclusive-entry-type
+++ a/include/linux/swap.h
@@ -74,14 +74,13 @@ static inline int current_is_kswapd(void
* to a special SWP_DEVICE_{READ|WRITE} entry.
*
* When a page is mapped by the device for exclusive access we set the CPU page
- * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
+ * table entries to a special SWP_DEVICE_EXCLUSIVE entry.
*/
#ifdef CONFIG_DEVICE_PRIVATE
-#define SWP_DEVICE_NUM 4
+#define SWP_DEVICE_NUM 3
#define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
#define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
-#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
-#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
+#define SWP_DEVICE_EXCLUSIVE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
#else
#define SWP_DEVICE_NUM 0
#endif
--- a/include/linux/swapops.h~mm-use-single-swp_device_exclusive-entry-type
+++ a/include/linux/swapops.h
@@ -186,26 +186,16 @@ static inline bool is_writable_device_pr
return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
}
-static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
+static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
- return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
-}
-
-static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
-{
- return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
+ return swp_entry(SWP_DEVICE_EXCLUSIVE, offset);
}
static inline bool is_device_exclusive_entry(swp_entry_t entry)
{
- return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
- swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
+ return swp_type(entry) == SWP_DEVICE_EXCLUSIVE;
}
-static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
-{
- return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
-}
#else /* CONFIG_DEVICE_PRIVATE */
static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
{
@@ -227,12 +217,7 @@ static inline bool is_writable_device_pr
return false;
}
-static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
-{
- return swp_entry(0, 0);
-}
-
-static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
+static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
return swp_entry(0, 0);
}
@@ -242,10 +227,6 @@ static inline bool is_device_exclusive_e
return false;
}
-static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
-{
- return false;
-}
#endif /* CONFIG_DEVICE_PRIVATE */
#ifdef CONFIG_MIGRATION
--- a/mm/mprotect.c~mm-use-single-swp_device_exclusive-entry-type
+++ a/mm/mprotect.c
@@ -225,14 +225,6 @@ static long change_pte_range(struct mmu_
newpte = swp_entry_to_pte(entry);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
- } else if (is_writable_device_exclusive_entry(entry)) {
- entry = make_readable_device_exclusive_entry(
- swp_offset(entry));
- newpte = swp_entry_to_pte(entry);
- if (pte_swp_soft_dirty(oldpte))
- newpte = pte_swp_mksoft_dirty(newpte);
- if (pte_swp_uffd_wp(oldpte))
- newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_pte_marker_entry(entry)) {
/*
* Ignore error swap entries unconditionally,
--- a/mm/page_table_check.c~mm-use-single-swp_device_exclusive-entry-type
+++ a/mm/page_table_check.c
@@ -196,9 +196,8 @@ EXPORT_SYMBOL(__page_table_check_pud_cle
/* Whether the swap entry cached writable information */
static inline bool swap_cached_writable(swp_entry_t entry)
{
- return is_writable_device_exclusive_entry(entry) ||
- is_writable_device_private_entry(entry) ||
- is_writable_migration_entry(entry);
+ return is_writable_device_private_entry(entry) ||
+ is_writable_migration_entry(entry);
}
static inline void page_table_check_pte_flags(pte_t pte)
--- a/mm/rmap.c~mm-use-single-swp_device_exclusive-entry-type
+++ a/mm/rmap.c
@@ -2492,7 +2492,7 @@ struct page *make_device_exclusive(struc
* do_swap_page() will trigger the conversion back while holding the
* folio lock.
*/
- entry = make_writable_device_exclusive_entry(page_to_pfn(page));
+ entry = make_device_exclusive_entry(page_to_pfn(page));
swp_pte = swp_entry_to_pte(entry);
if (pte_soft_dirty(fw.pte))
swp_pte = pte_swp_mksoft_dirty(swp_pte);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-gup-reject-foll_split_pmd-with-hugetlb-vmas.patch
mm-rmap-reject-hugetlb-folios-in-folio_make_device_exclusive.patch
mm-rmap-convert-make_device_exclusive_range-to-make_device_exclusive.patch
mm-rmap-implement-make_device_exclusive-using-folio_walk-instead-of-rmap-walk.patch
mm-memory-detect-writability-in-restore_exclusive_pte-through-can_change_pte_writable.patch
mm-use-single-swp_device_exclusive-entry-type.patch
mm-page_vma_mapped-device-exclusive-entries-are-not-migration-entries.patch
kernel-events-uprobes-handle-device-exclusive-entries-correctly-in-__replace_page.patch
mm-ksm-handle-device-exclusive-entries-correctly-in-write_protect_page.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-try_to_unmap_one.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-try_to_migrate_one.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-page_vma_mkclean_one.patch
mm-page_idle-handle-device-exclusive-entries-correctly-in-page_idle_clear_pte_refs_one.patch
mm-damon-handle-device-exclusive-entries-correctly-in-damon_folio_young_one.patch
mm-damon-handle-device-exclusive-entries-correctly-in-damon_folio_mkold_one.patch
mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries.patch
mm-rmap-avoid-ebusy-from-make_device_exclusive.patch
