We can use debug_pagealloc_enabled() to check if we can map
the identity mapping with 2MB pages. We can also add the state
into the dump_stack output.
The patch does not touch the code for the 1GB pages, which ignored
CONFIG_DEBUG_PAGEALLOC. Do we need to fence this as well?
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/x86/kernel/dumpstack.c | 4 +++-
arch/x86/mm/init.c | 7 ++++---
arch/x86/mm/pageattr.c | 14 ++++----------
3 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 9c30acf..7971638 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -266,7 +266,9 @@ int __die(const char *str, struct pt_regs *regs, long err)
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
- printk("DEBUG_PAGEALLOC ");
+ printk("DEBUG_PAGEALLOC(%s) ",
+ debug_pagealloc_enabled() ? "enabled" : "disabled");
+
#endif
#ifdef CONFIG_KASAN
printk("KASAN");
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 493f541..39823fd 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -150,13 +150,14 @@ static int page_size_mask;
static void __init probe_page_size_mask(void)
{
-#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
+#if !defined(CONFIG_KMEMCHECK)
/*
- * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
+ * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
+ * use small pages.
* This will simplify cpa(), which otherwise needs to support splitting
* large pages into small in interrupt context, etc.
*/
- if (cpu_has_pse)
+ if (cpu_has_pse && !debug_pagealloc_enabled())
page_size_mask |= 1 << PG_LEVEL_2M;
#endif
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a3137a4..a49c8fd 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -103,12 +103,6 @@ static inline unsigned long highmap_end_pfn(void)
#endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
-# define debug_pagealloc 1
-#else
-# define debug_pagealloc 0
-#endif
-
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
{
@@ -703,10 +697,10 @@ static int split_large_page(struct cpa_data *cpa, pte_t *kpte,
{
struct page *base;
- if (!debug_pagealloc)
+ if (!debug_pagealloc_enabled())
spin_unlock(&cpa_lock);
base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0);
- if (!debug_pagealloc)
+ if (!debug_pagealloc_enabled())
spin_lock(&cpa_lock);
if (!base)
return -ENOMEM;
@@ -1326,10 +1320,10 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias)
if (cpa->flags & (CPA_ARRAY | CPA_PAGES_ARRAY))
cpa->numpages = 1;
- if (!debug_pagealloc)
+ if (!debug_pagealloc_enabled())
spin_lock(&cpa_lock);
ret = __change_page_attr(cpa, checkalias);
- if (!debug_pagealloc)
+ if (!debug_pagealloc_enabled())
spin_unlock(&cpa_lock);
if (ret)
return ret;
--
2.3.0
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