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 bba850b..db28aa9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -641,13 +641,6 @@
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 9cf2fea..dd49b16 100644
--- a/arch/x86/mm/pageattr_32.c
+++ b/arch/x86/mm/pageattr_32.c
@@ -61,13 +61,17 @@
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;
@@ -219,6 +223,12 @@
}
/*
+ * 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 9411a2d..fccb563 100644
--- a/include/asm-x86/cacheflush.h
+++ b/include/asm-x86/cacheflush.h
@@ -29,11 +29,6 @@
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 3c22d97..1bba678 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1118,9 +1118,21 @@
}
#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 3316dff..cb81ed1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -318,6 +318,10 @@
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 @@
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,