[PATCH v3 2/3] x86: query dynamic DEBUG_PAGEALLOC setting
From: Christian Borntraeger <hidden>
Date: 2016-01-27 10:11:02
Also in:
linux-arch, linux-mm, linux-s390, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm, x86 stack unwinding · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra, Josh Poimboeuf
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 <redacted> Reviewed-by: Thomas Gleixner <redacted> --- 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 9c30acf..32e5699 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 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 fc6a4c8..5f68987 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) {
@@ -708,10 +702,10 @@ 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;
@@ -1331,10 +1325,10 @@ 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