Commit 288cf3c6 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Linus Torvalds
Browse files

x86: query dynamic DEBUG_PAGEALLOC setting 



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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8df651c7

arch/x86/kernel/dumpstack.c

+2 −3
Original line number Diff line number Diff line
@@ -265,9 +265,8 @@ int __die(const char *str, struct pt_regs *regs, long err) 
#ifdef CONFIG_SMP

	printk("SMP ");

#endif

#ifdef CONFIG_DEBUG_PAGEALLOC

	if (debug_pagealloc_enabled())

		printk("DEBUG_PAGEALLOC ");

#endif

#ifdef CONFIG_KASAN

	printk("KASAN");

#endif

arch/x86/mm/init.c

+4 −3
Original line number Diff line number Diff line
@@ -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

arch/x86/mm/pageattr.c

+4 −10
Original line number Diff line number Diff line
@@ -106,12 +106,6 @@ 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)

{
@@ -714,10 +708,10 @@ 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;
@@ -1337,10 +1331,10 @@ 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;

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