From 288cf3c64e4522d28349de5345348574cbe9df83 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 15 Mar 2016 14:57:33 -0700 Subject: [PATCH] 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: Christian Borntraeger Reviewed-by: Thomas Gleixner Acked-by: David Rientjes Cc: Laura Abbott Cc: Joonsoo Kim Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/kernel/dumpstack.c | 5 ++--- arch/x86/mm/init.c | 7 ++++--- arch/x86/mm/pageattr.c | 14 ++++---------- 3 files changed, 10 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 9c30acfadae2..32e5699eadfe 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -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 - printk("DEBUG_PAGEALLOC "); -#endif + if (debug_pagealloc_enabled()) + printk("DEBUG_PAGEALLOC "); #ifdef CONFIG_KASAN printk("KASAN"); #endif diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 493f54172b4a..39823fd91396 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 1c37e650acac..e64a4703f8b1 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -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; -- 2.20.1