x86: do not PSE on CONFIG_DEBUG_PAGEALLOC=y

get more testing of the c_p_a() code done by not turning off
PSE on DEBUG_PAGEALLOC.

this simplifies the early pagetable setup code, and tests
the largepage-splitup code quite heavily.

In the end, all the largepages will be split up pretty quickly,
so there's no difference to how DEBUG_PAGEALLOC worked before.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index bba850b05d0e4b946bd1c4a982a3213c93f2b1ce..db28aa9e2f694b7f14669d3c66df8cc712cfab48 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -641,13 +641,6 @@ void __init early_cpu_init(void)
        nexgen_init_cpu();
        umc_init_cpu();
        early_cpu_detect();
-
-#ifdef CONFIG_DEBUG_PAGEALLOC
-       /* pse is not compatible with on-the-fly unmapping,
-        * disable it even if the cpus claim to support it.
-        */
-       setup_clear_cpu_cap(X86_FEATURE_PSE);
-#endif
 }
 
 /* Make sure %fs is initialized properly in idle threads */

diff --git a/arch/x86/mm/pageattr_32.c b/arch/x86/mm/pageattr_32.c
index 9cf2fea54eb5085ea44be387b03ac0b07010cab9..dd49b16b3a0ec08941990c75c61c367064110e01 100644 (file)
--- a/arch/x86/mm/pageattr_32.c
+++ b/arch/x86/mm/pageattr_32.c
@@ -61,13 +61,17 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 static int split_large_page(pte_t *kpte, unsigned long address)
 {
        pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+       gfp_t gfp_flags = GFP_KERNEL;
        unsigned long flags;
        unsigned long addr;
        pte_t *pbase, *tmp;
        struct page *base;
        int i, level;
 
-       base = alloc_pages(GFP_KERNEL, 0);
+#ifdef CONFIG_DEBUG_PAGEALLOC
+       gfp_flags = GFP_ATOMIC;
+#endif
+       base = alloc_pages(gfp_flags, 0);
        if (!base)
                return -ENOMEM;
 
@@ -218,6 +222,12 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
                                           numpages * PAGE_SIZE);
        }
 
+       /*
+        * If page allocator is not up yet then do not call c_p_a():
+        */
+       if (!debug_pagealloc_enabled)
+               return;
+
        /*
         * the return value is ignored - the calls cannot fail,
         * large pages are disabled at boot time.

diff --git a/include/asm-x86/cacheflush.h b/include/asm-x86/cacheflush.h
index 9411a2d3f19c2a77feed8d141ddc7c3bd9f13399..fccb563e230555ca483fddad09a7cf051d3eeddb 100644 (file)
--- a/include/asm-x86/cacheflush.h
+++ b/include/asm-x86/cacheflush.h
@@ -29,11 +29,6 @@ int change_page_attr(struct page *page, int numpages, pgprot_t prot);
 int change_page_attr_addr(unsigned long addr, int numpages, pgprot_t prot);
 void clflush_cache_range(void *addr, int size);
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-/* internal debugging function */
-void kernel_map_pages(struct page *page, int numpages, int enable);
-#endif
-
 #ifdef CONFIG_DEBUG_RODATA
 void mark_rodata_ro(void);
 #endif

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3c22d971afa78576db7a96597fe518a33b07e985..1bba6789a50a39cd1139a7b0556df38fcd78624e 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1118,9 +1118,21 @@ static inline void vm_stat_account(struct mm_struct *mm,
 }
 #endif /* CONFIG_PROC_FS */
 
-#ifndef CONFIG_DEBUG_PAGEALLOC
+#ifdef CONFIG_DEBUG_PAGEALLOC
+extern int debug_pagealloc_enabled;
+
+extern void kernel_map_pages(struct page *page, int numpages, int enable);
+
+static inline void enable_debug_pagealloc(void)
+{
+       debug_pagealloc_enabled = 1;
+}
+#else
 static inline void
 kernel_map_pages(struct page *page, int numpages, int enable) {}
+static inline void enable_debug_pagealloc(void)
+{
+}
 #endif
 
 extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);

diff --git a/init/main.c b/init/main.c
index 3316dffe3e572cd0ca37c63bd9f3e4d972f03d61..cb81ed116f62b3cadbde986e508081295c0446d9 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -318,6 +318,10 @@ static int __init unknown_bootoption(char *param, char *val)
        return 0;
 }
 
+#ifdef CONFIG_DEBUG_PAGEALLOC
+int __read_mostly debug_pagealloc_enabled = 0;
+#endif
+
 static int __init init_setup(char *str)
 {
        unsigned int i;
@@ -552,6 +556,7 @@ asmlinkage void __init start_kernel(void)
        preempt_disable();
        build_all_zonelists();
        page_alloc_init();
+       enable_debug_pagealloc();
        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
        parse_early_param();
        parse_args("Booting kernel", static_command_line, __start___param,