The patch titled
Subject: proc/smaps: add PMDMappable field to smaps
has been added to the -mm mm-unstable branch. Its filename is
proc-smaps-add-pmdmappable-field-to-smaps.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/proc-smaps-add-pmdmappable-field-to-smaps.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: "Zach O'Keefe" <zokeefe@xxxxxxxxxx>
Subject: proc/smaps: add PMDMappable field to smaps
Date: Wed, 6 Jul 2022 16:59:31 -0700
Add PMDMappable field to smaps output which informs the user if memory in
the VMA can be PMD-mapped by MADV_COLLAPSE.
The distinction from THPeligible is needed for two reasons:
1) For THP, MADV_COLLAPSE is not coupled to THP sysfs controls, which
THPeligible reports.
2) PMDMappable can also be used in HugeTLB fine-granularity mappings,
which are independent from THP.
Link: https://lkml.kernel.org/r/20220706235936.2197195-14-zokeefe@xxxxxxxxxx
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Chris Kennelly <ckennelly@xxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Pavel Begunkov <asml.silence@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rongwei Wang <rongwei.wang@xxxxxxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/proc.rst | 10 ++++++++--
fs/proc/task_mmu.c | 2 ++
2 files changed, 10 insertions(+), 2 deletions(-)
--- a/Documentation/filesystems/proc.rst~proc-smaps-add-pmdmappable-field-to-smaps
+++ a/Documentation/filesystems/proc.rst
@@ -466,6 +466,7 @@ Memory Area, or VMA) there is a series o
MMUPageSize: 4 kB
Locked: 0 kB
THPeligible: 0
+ PMDMappable: 0
VmFlags: rd ex mr mw me dw
The first of these lines shows the same information as is displayed for the
@@ -518,9 +519,14 @@ replaced by copy-on-write) part of the u
does not take into account swapped out page of underlying shmem objects.
"Locked" indicates whether the mapping is locked in memory or not.
+"PMDMappable" indicates if the memory can be mapped by PMDs - 1 if true, 0
+otherwise. It just shows the current status. Note that this is memory
+operable on explicitly by MADV_COLLAPSE.
+
"THPeligible" indicates whether the mapping is eligible for allocating THP
-pages as well as the THP is PMD mappable or not - 1 if true, 0 otherwise.
-It just shows the current status.
+pages by the kernel, as well as the THP is PMD mappable or not - 1 if true, 0
+otherwise. It just shows the current status. Note this is memory the kernel can
+transparently provide as THPs.
"VmFlags" field deserves a separate description. This member represents the
kernel flags associated with the particular virtual memory area in two letter
--- a/fs/proc/task_mmu.c~proc-smaps-add-pmdmappable-field-to-smaps
+++ a/fs/proc/task_mmu.c
@@ -867,6 +867,8 @@ static int show_smap(struct seq_file *m,
seq_printf(m, "THPeligible: %d\n",
hugepage_vma_check(vma, vma->vm_flags, true, false, true));
+ seq_printf(m, "PMDMappable: %d\n",
+ hugepage_vma_check(vma, vma->vm_flags, true, false, false));
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
_
Patches currently in -mm which might be from zokeefe@xxxxxxxxxx are
mm-khugepaged-remove-redundant-transhuge_vma_suitable-check.patch
mm-khugepaged-add-struct-collapse_control.patch
mm-khugepaged-dedup-and-simplify-hugepage-alloc-and-charging.patch
mm-khugepaged-pipe-enum-scan_result-codes-back-to-callers.patch
mm-khugepaged-add-flag-to-predicate-khugepaged-only-behavior.patch
mm-thp-add-flag-to-enforce-sysfs-thp-in-hugepage_vma_check.patch
mm-khugepaged-record-scan_pmd_mapped-when-scan_pmd-finds-hugepage.patch
mm-madvise-introduce-madv_collapse-sync-hugepage-collapse.patch
mm-khugepaged-rename-prefix-of-shared-collapse-functions.patch
mm-madvise-add-huge_memory-mm_madvise_collapse-tracepoint.patch
mm-madvise-add-madv_collapse-to-process_madvise.patch
proc-smaps-add-pmdmappable-field-to-smaps.patch
selftests-vm-modularize-collapse-selftests.patch
selftests-vm-dedup-hugepage-allocation-logic.patch
selftests-vm-add-madv_collapse-collapse-context-to-selftests.patch
selftests-vm-add-selftest-to-verify-recollapse-of-thps.patch
selftests-vm-add-selftest-to-verify-multi-thp-collapse.patch
