The patch titled
Subject: mm/khugepaged: fix struct collapse_control load_node definition
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-add-struct-collapse_control-fix-fix-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-add-struct-collapse_control-fix-fix-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: "Zach O'Keefe" <zokeefe@xxxxxxxxxx>
Subject: mm/khugepaged: fix struct collapse_control load_node definition
Date: Fri, 2 Sep 2022 19:12:21 -0700
HPAGE_PMD_ORDER is used to determine a minimal amount of bits needed to
store per-node counters in struct collapse_control, defining the array to
be either a u16[HPAGE_PMD_ORDER] or u32[HPAGE_PMD_ORDER].
For some architectures/configs, HPAGE_PMD_ORDER isn't resolved at
preprocessor time (suitable for resolving preprocessor directives) but
rather expands into a compiler built-in that is resolved at compile-time.
E.g. for 32-bit MIPS (see link for full config):
---8<--
>> arch/mips/include/asm/pgtable.h:238:26: warning: "__builtin_ffs" is not defined, evaluates to 0 [-Wundef]
238 | #define PTE_T_LOG2 (__builtin_ffs(sizeof(pte_t)) - 1)
| ^~~~~~~~~~~~~
arch/mips/include/asm/pgtable-32.h:65:43: note: in expansion of macro 'PTE_T_LOG2'
65 | # define PGDIR_SHIFT (2 * PAGE_SHIFT - PTE_T_LOG2 - 1)
| ^~~~~~~~~~
include/asm-generic/pgtable-nop4d.h:11:33: note: in expansion of macro 'PGDIR_SHIFT'
11 | #define P4D_SHIFT PGDIR_SHIFT
| ^~~~~~~~~~~
include/asm-generic/pgtable-nopud.h:18:25: note: in expansion of macro 'P4D_SHIFT'
18 | #define PUD_SHIFT P4D_SHIFT
| ^~~~~~~~~
include/asm-generic/pgtable-nopmd.h:20:25: note: in expansion of macro 'PUD_SHIFT'
20 | #define PMD_SHIFT PUD_SHIFT
| ^~~~~~~~~
include/linux/huge_mm.h:109:25: note: in expansion of macro 'PMD_SHIFT'
109 | #define HPAGE_PMD_SHIFT PMD_SHIFT
| ^~~~~~~~~
include/linux/huge_mm.h:105:26: note: in expansion of macro 'HPAGE_PMD_SHIFT'
105 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
| ^~~~~~~~~~~~~~~
mm/khugepaged.c:90:5: note: in expansion of macro 'HPAGE_PMD_ORDER'
90 | #if HPAGE_PMD_ORDER < 16
| ^~~~~~~~~~~~~~~
>> arch/mips/include/asm/pgtable.h:238:39: error: missing binary operator before token "("
238 | #define PTE_T_LOG2 (__builtin_ffs(sizeof(pte_t)) - 1)
| ^
arch/mips/include/asm/pgtable-32.h:65:43: note: in expansion of macro 'PTE_T_LOG2'
65 | # define PGDIR_SHIFT (2 * PAGE_SHIFT - PTE_T_LOG2 - 1)
| ^~~~~~~~~~
include/asm-generic/pgtable-nop4d.h:11:33: note: in expansion of macro 'PGDIR_SHIFT'
11 | #define P4D_SHIFT PGDIR_SHIFT
| ^~~~~~~~~~~
include/asm-generic/pgtable-nopud.h:18:25: note: in expansion of macro 'P4D_SHIFT'
18 | #define PUD_SHIFT P4D_SHIFT
| ^~~~~~~~~
include/asm-generic/pgtable-nopmd.h:20:25: note: in expansion of macro 'PUD_SHIFT'
20 | #define PMD_SHIFT PUD_SHIFT
| ^~~~~~~~~
include/linux/huge_mm.h:109:25: note: in expansion of macro 'PMD_SHIFT'
109 | #define HPAGE_PMD_SHIFT PMD_SHIFT
| ^~~~~~~~~
include/linux/huge_mm.h:105:26: note: in expansion of macro 'HPAGE_PMD_SHIFT'
105 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
| ^~~~~~~~~~~~~~~
mm/khugepaged.c:90:5: note: in expansion of macro 'HPAGE_PMD_ORDER'
90 | #if HPAGE_PMD_ORDER < 16
| ^~~~~~~~~~~~~~~
---8<--
load_node is already special-cased for CONFIG_PPC64 in
"mm-khugepaged-add-struct-collapse_control-fix-fix", and we could continue
down that path by #define'ing away edge cases, but I think at this point
it easier to just let load_node be an array of u32s. If it's ever an
issue, we can revisit.
This essentially rolls back both:
"mm/khugepaged: use minimal bits to store num page < HPAGE_PMD_NR"
"mm-khugepaged-add-struct-collapse_control-fix-fix"
(though we'll leave it as a u32 vs an int).
Link: https://lore.kernel.org/linux-mm/202209021349.F73i5d6X-lkp@xxxxxxxxx/
Link: https://lkml.kernel.org/r/20220903021221.1130021-1-zokeefe@xxxxxxxxxx
Fixes: 5f7bb00bd9cd ("mm/khugepaged: use minimal bits to store num page < HPAGE_PMD_NR")
Fixes: 03053c821af2 ("mm-khugepaged-add-struct-collapse_control-fix-fix")
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
--- a/mm/khugepaged.c~mm-khugepaged-add-struct-collapse_control-fix-fix-fix
+++ a/mm/khugepaged.c
@@ -87,13 +87,8 @@ static struct kmem_cache *mm_slot_cache
struct collapse_control {
/* Num pages scanned per node */
-#if defined(CONFIG_PPC64)
u32 node_load[MAX_NUMNODES];
-#elif HPAGE_PMD_ORDER < 16
- u16 node_load[MAX_NUMNODES];
-#else
- u32 node_load[MAX_NUMNODES];
-#endif
+
/* Last target selected in khugepaged_find_target_node() */
int last_target_node;
};
_
Patches currently in -mm which might be from zokeefe@xxxxxxxxxx are
mm-khugepaged-add-struct-collapse_control.patch
mm-khugepaged-add-struct-collapse_control-fix.patch
mm-khugepaged-add-struct-collapse_control-fix-fix-fix.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-add-flag-to-predicate-khugepaged-only-behavior-fix.patch
mm-khugepaged-record-scan_pmd_mapped-when-scan_pmd-finds-hugepage.patch
mm-madvise-introduce-madv_collapse-sync-hugepage-collapse.patch
mm-madvise-introduce-madv_collapse-sync-hugepage-collapse-fix-2.patch
mm-madvise-introduce-madv_collapse-sync-hugepage-collapse-fix-3.patch
mm-khugepaged-rename-prefix-of-shared-collapse-functions.patch
mm-madvise-add-madv_collapse-to-process_madvise.patch
mm-madvise-add-madv_collapse-to-process_madvise-fix.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
