The patch titled
Subject: mm/debug_vm_pgtable: ensure THP availability via has_transparent_hugepage()
has been added to the -mm tree. Its filename is
mm-debug_vm_pgtable-ensure-thp-availability-via-has_transparent_hugepage.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-ensure-thp-availability-via-has_transparent_hugepage.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-ensure-thp-availability-via-has_transparent_hugepage.patch
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------------------------------------------------------
From: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Subject: mm/debug_vm_pgtable: ensure THP availability via has_transparent_hugepage()
On certain platforms, THP support could not just be validated via the
build option CONFIG_TRANSPARENT_HUGEPAGE. Instead
has_transparent_hugepage() also needs to be called upon to verify THP
runtime support. Otherwise the debug test will just run into unusable THP
helpers like in the case of a 4K hash config on powerpc platform [1].
This just moves all pfn_pmd() and pfn_pud() after THP runtime validation
with has_transparent_hugepage() which prevents the mentioned problem.
[1] https://bugzilla.kernel.org/show_bug.cgi?id=213069
Link: https://lkml.kernel.org/r/1621397588-19211-1-git-send-email-anshuman.khandual@xxxxxxx
Fixes: 787d563b8642 ("mm/debug_vm_pgtable: fix kernel crash by checking for THP support")
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/debug_vm_pgtable.c | 63 ++++++++++++++++++++++++++++++++--------
1 file changed, 51 insertions(+), 12 deletions(-)
--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-ensure-thp-availability-via-has_transparent_hugepage
+++ a/mm/debug_vm_pgtable.c
@@ -146,13 +146,14 @@ static void __init pte_savedwrite_tests(
static void __init pmd_basic_tests(unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
- pmd_t pmd = pfn_pmd(pfn, prot);
unsigned long val = idx, *ptr = &val;
+ pmd_t pmd;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD basic (%pGv)\n", ptr);
+ pmd = pfn_pmd(pfn, prot);
/*
* This test needs to be executed after the given page table entry
@@ -185,7 +186,7 @@ static void __init pmd_advanced_tests(st
unsigned long pfn, unsigned long vaddr,
pgprot_t prot, pgtable_t pgtable)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
if (!has_transparent_hugepage())
return;
@@ -232,9 +233,14 @@ static void __init pmd_advanced_tests(st
static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
+
+ if (!has_transparent_hugepage())
+ return;
pr_debug("Validating PMD leaf\n");
+ pmd = pfn_pmd(pfn, prot);
+
/*
* PMD based THP is a leaf entry.
*/
@@ -267,12 +273,16 @@ static void __init pmd_huge_tests(pmd_t
static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
return;
+ if (!has_transparent_hugepage())
+ return;
+
pr_debug("Validating PMD saved write\n");
+ pmd = pfn_pmd(pfn, prot);
WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
}
@@ -281,13 +291,14 @@ static void __init pmd_savedwrite_tests(
static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
- pud_t pud = pfn_pud(pfn, prot);
unsigned long val = idx, *ptr = &val;
+ pud_t pud;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PUD basic (%pGv)\n", ptr);
+ pud = pfn_pud(pfn, prot);
/*
* This test needs to be executed after the given page table entry
@@ -323,7 +334,7 @@ static void __init pud_advanced_tests(st
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
- pud_t pud = pfn_pud(pfn, prot);
+ pud_t pud;
if (!has_transparent_hugepage())
return;
@@ -332,6 +343,7 @@ static void __init pud_advanced_tests(st
/* Align the address wrt HPAGE_PUD_SIZE */
vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE;
+ pud = pfn_pud(pfn, prot);
set_pud_at(mm, vaddr, pudp, pud);
pudp_set_wrprotect(mm, vaddr, pudp);
pud = READ_ONCE(*pudp);
@@ -370,9 +382,13 @@ static void __init pud_advanced_tests(st
static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
{
- pud_t pud = pfn_pud(pfn, prot);
+ pud_t pud;
+
+ if (!has_transparent_hugepage())
+ return;
pr_debug("Validating PUD leaf\n");
+ pud = pfn_pud(pfn, prot);
/*
* PUD based THP is a leaf entry.
*/
@@ -654,12 +670,16 @@ static void __init pte_protnone_tests(un
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
+ pmd_t pmd;
if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
return;
+ if (!has_transparent_hugepage())
+ return;
+
pr_debug("Validating PMD protnone\n");
+ pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
WARN_ON(!pmd_protnone(pmd));
WARN_ON(!pmd_present(pmd));
}
@@ -679,18 +699,26 @@ static void __init pte_devmap_tests(unsi
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
+
+ if (!has_transparent_hugepage())
+ return;
pr_debug("Validating PMD devmap\n");
+ pmd = pfn_pmd(pfn, prot);
WARN_ON(!pmd_devmap(pmd_mkdevmap(pmd)));
}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot)
{
- pud_t pud = pfn_pud(pfn, prot);
+ pud_t pud;
+
+ if (!has_transparent_hugepage())
+ return;
pr_debug("Validating PUD devmap\n");
+ pud = pfn_pud(pfn, prot);
WARN_ON(!pud_devmap(pud_mkdevmap(pud)));
}
#else /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
@@ -733,25 +761,33 @@ static void __init pte_swap_soft_dirty_t
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
return;
+ if (!has_transparent_hugepage())
+ return;
+
pr_debug("Validating PMD soft dirty\n");
+ pmd = pfn_pmd(pfn, prot);
WARN_ON(!pmd_soft_dirty(pmd_mksoft_dirty(pmd)));
WARN_ON(pmd_soft_dirty(pmd_clear_soft_dirty(pmd)));
}
static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
{
- pmd_t pmd = pfn_pmd(pfn, prot);
+ pmd_t pmd;
if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
!IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
return;
+ if (!has_transparent_hugepage())
+ return;
+
pr_debug("Validating PMD swap soft dirty\n");
+ pmd = pfn_pmd(pfn, prot);
WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd)));
WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd)));
}
@@ -780,6 +816,9 @@ static void __init pmd_swap_tests(unsign
swp_entry_t swp;
pmd_t pmd;
+ if (!has_transparent_hugepage())
+ return;
+
pr_debug("Validating PMD swap\n");
pmd = pfn_pmd(pfn, prot);
swp = __pmd_to_swp_entry(pmd);
_
Patches currently in -mm which might be from anshuman.khandual@xxxxxxx are
mm-debug_vm_pgtable-ensure-thp-availability-via-has_transparent_hugepage.patch
mm-thp-update-mm_structs-mm_anonpages-stat-for-huge-zero-pages.patch
mm-thp-make-alloc_split_ptlocks-dependent-on-use_split_pte_ptlocks.patch
mm-define-default-value-for-first_user_address.patch
