The patch titled
Subject: mm: introduce pte_move_swp_offset() helper which can move offset bidirectionally
has been added to the -mm mm-unstable branch. Its filename is
mm-introduce-pte_move_swp_offset-helper-which-can-move-offset-bidirectionally.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-pte_move_swp_offset-helper-which-can-move-offset-bidirectionally.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: Barry Song <v-songbaohua@xxxxxxxx>
Subject: mm: introduce pte_move_swp_offset() helper which can move offset bidirectionally
Date: Wed, 29 May 2024 20:28:21 +1200
There could arise a necessity to obtain the first pte_t from a swap pte_t
located in the middle. For instance, this may occur within the context of
do_swap_page(), where a page fault can potentially occur in any PTE of a
large folio. To address this, the following patch introduces
pte_move_swp_offset(), a function capable of bidirectional movement by a
specified delta argument. Consequently, pte_next_swp_offset() will
directly invoke it with delta = 1.
Link: https://lkml.kernel.org/r/20240529082824.150954-4-21cnbao@xxxxxxxxx
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Suggested-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Chuanhua Han <hanchuanhua@xxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Gao Xiang <xiang@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kairui Song <kasong@xxxxxxxxxxx>
Cc: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
--- a/mm/internal.h~mm-introduce-pte_move_swp_offset-helper-which-can-move-offset-bidirectionally
+++ a/mm/internal.h
@@ -211,18 +211,21 @@ static inline int folio_pte_batch(struct
}
/**
- * pte_next_swp_offset - Increment the swap entry offset field of a swap pte.
+ * pte_move_swp_offset - Move the swap entry offset field of a swap pte
+ * forward or backward by delta
* @pte: The initial pte state; is_swap_pte(pte) must be true and
* non_swap_entry() must be false.
+ * @delta: The direction and the offset we are moving; forward if delta
+ * is positive; backward if delta is negative
*
- * Increments the swap offset, while maintaining all other fields, including
+ * Moves the swap offset, while maintaining all other fields, including
* swap type, and any swp pte bits. The resulting pte is returned.
*/
-static inline pte_t pte_next_swp_offset(pte_t pte)
+static inline pte_t pte_move_swp_offset(pte_t pte, long delta)
{
swp_entry_t entry = pte_to_swp_entry(pte);
pte_t new = __swp_entry_to_pte(__swp_entry(swp_type(entry),
- (swp_offset(entry) + 1)));
+ (swp_offset(entry) + delta)));
if (pte_swp_soft_dirty(pte))
new = pte_swp_mksoft_dirty(new);
@@ -234,6 +237,20 @@ static inline pte_t pte_next_swp_offset(
return new;
}
+
+/**
+ * pte_next_swp_offset - Increment the swap entry offset field of a swap pte.
+ * @pte: The initial pte state; is_swap_pte(pte) must be true and
+ * non_swap_entry() must be false.
+ *
+ * Increments the swap offset, while maintaining all other fields, including
+ * swap type, and any swp pte bits. The resulting pte is returned.
+ */
+static inline pte_t pte_next_swp_offset(pte_t pte)
+{
+ return pte_move_swp_offset(pte, 1);
+}
+
/**
* swap_pte_batch - detect a PTE batch for a set of contiguous swap entries
* @start_ptep: Page table pointer for the first entry.
_
Patches currently in -mm which might be from v-songbaohua@xxxxxxxx are
mm-huge_mm-fix-undefined-reference-to-mthp_stats-for-config_sysfs=n.patch
mm-arm64-fix-the-out-of-bounds-issue-in-contpte_clear_young_dirty_ptes.patch
mm-remove-the-implementation-of-swap_free-and-always-use-swap_free_nr.patch
mm-introduce-pte_move_swp_offset-helper-which-can-move-offset-bidirectionally.patch
mm-introduce-arch_do_swap_page_nr-which-allows-restore-metadata-for-nr-pages.patch
