The patch titled
Subject: mm-introduce-a-pageflag-for-partially-mapped-folios-fix
has been added to the -mm mm-unstable branch. Its filename is
mm-introduce-a-pageflag-for-partially-mapped-folios-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-a-pageflag-for-partially-mapped-folios-fix.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: Usama Arif <usamaarif642@xxxxxxxxx>
Subject: mm-introduce-a-pageflag-for-partially-mapped-folios-fix
Date: Thu, 15 Aug 2024 16:25:09 +0100
don't clear partially mapped bit in hugeTLB folios and fix deferred split THP stats
Link: https://lkml.kernel.org/r/4acdf2b7-ed65-4087-9806-8f4a187b4eb5@xxxxxxxxx
Signed-off-by: Usama Arif <usamaarif642@xxxxxxxxx>
Cc: Barry Song <baohua@xxxxxxxxxx>
Cc: Alexander Zhu <alexlzhu@xxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Cc: Huan Yang <link@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Kairui Song <ryncsn@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Shuang Zhai <zhais@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 1 +
mm/huge_memory.c | 14 ++++++++------
mm/hugetlb.c | 1 -
mm/rmap.c | 2 +-
4 files changed, 10 insertions(+), 8 deletions(-)
--- a/include/linux/page-flags.h~mm-introduce-a-pageflag-for-partially-mapped-folios-fix
+++ a/include/linux/page-flags.h
@@ -863,6 +863,7 @@ static inline void ClearPageCompound(str
}
FOLIO_FLAG(large_rmappable, FOLIO_SECOND_PAGE)
FOLIO_FLAG(partially_mapped, FOLIO_SECOND_PAGE)
+FOLIO_TEST_SET_FLAG(partially_mapped, FOLIO_SECOND_PAGE)
#else
FOLIO_FLAG_FALSE(large_rmappable)
FOLIO_FLAG_FALSE(partially_mapped)
--- a/mm/huge_memory.c~mm-introduce-a-pageflag-for-partially-mapped-folios-fix
+++ a/mm/huge_memory.c
@@ -3452,6 +3452,7 @@ void __folio_undo_large_rmappable(struct
spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
}
+/* partially_mapped=false won't clear PG_partially_mapped folio flag */
void deferred_split_folio(struct folio *folio, bool partially_mapped)
{
struct deferred_split *ds_queue = get_deferred_split_queue(folio);
@@ -3481,16 +3482,17 @@ void deferred_split_folio(struct folio *
return;
spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
- if (partially_mapped)
- folio_set_partially_mapped(folio);
- else
- folio_clear_partially_mapped(folio);
- if (list_empty(&folio->_deferred_list)) {
- if (partially_mapped) {
+ if (partially_mapped) {
+ if (!folio_test_set_partially_mapped(folio)) {
if (folio_test_pmd_mappable(folio))
count_vm_event(THP_DEFERRED_SPLIT_PAGE);
count_mthp_stat(folio_order(folio), MTHP_STAT_SPLIT_DEFERRED);
}
+ } else {
+ /* partially mapped folios cannot become non-partially mapped */
+ VM_WARN_ON_FOLIO(folio_test_partially_mapped(folio), folio);
+ }
+ if (list_empty(&folio->_deferred_list)) {
list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
ds_queue->split_queue_len++;
#ifdef CONFIG_MEMCG
--- a/mm/hugetlb.c~mm-introduce-a-pageflag-for-partially-mapped-folios-fix
+++ a/mm/hugetlb.c
@@ -1758,7 +1758,6 @@ static void __update_and_free_hugetlb_fo
free_gigantic_folio(folio, huge_page_order(h));
} else {
INIT_LIST_HEAD(&folio->_deferred_list);
- folio_clear_partially_mapped(folio);
folio_put(folio);
}
}
--- a/mm/rmap.c~mm-introduce-a-pageflag-for-partially-mapped-folios-fix
+++ a/mm/rmap.c
@@ -1578,7 +1578,7 @@ static __always_inline void __folio_remo
* Check partially_mapped first to ensure it is a large folio.
*/
if (partially_mapped && folio_test_anon(folio) &&
- list_empty(&folio->_deferred_list))
+ !folio_test_partially_mapped(folio))
deferred_split_folio(folio, true);
__folio_mod_stat(folio, -nr, -nr_pmdmapped);
_
Patches currently in -mm which might be from usamaarif642@xxxxxxxxx are
mm-free-zapped-tail-pages-when-splitting-isolated-thp-fix.patch
mm-introduce-a-pageflag-for-partially-mapped-folios.patch
mm-introduce-a-pageflag-for-partially-mapped-folios-fix.patch
mm-split-underutilized-thps.patch
mm-add-sysfs-entry-to-disable-splitting-underutilized-thps.patch
