x86, generic: CPA add statistics about state of direct mapping v4
Add information about the mapping state of the direct mapping to
/proc/meminfo. I chose /proc/meminfo because that is where all the other
memory statistics are too and it is a generally useful metric even
outside debugging situations. A lot of split kernel pages means the
kernel will run slower.
This way we can see how many large pages are really used for it and how
many are split.
Useful for general insight into the kernel.
v2: Add hotplug locking to 64bit to plug a very obscure theoretical race.
32bit doesn't need it because it doesn't support hotadd for lowmem.
Fix some typos
v3: Rename dpages_cnt
Add CONFIG ifdef for count update as requested by tglx
Expand description
v4: Fix stupid bugs added in v3
Move update_page_count to pageattr.c
Signed-off-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index ec30d10..0269ac2 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -162,6 +162,7 @@
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
+ unsigned pages_2m = 0, pages_4k = 0;
pgd_idx = pgd_index(PAGE_OFFSET);
pgd = pgd_base + pgd_idx;
@@ -197,6 +198,7 @@
is_kernel_text(addr2))
prot = PAGE_KERNEL_LARGE_EXEC;
+ pages_2m++;
set_pmd(pmd, pfn_pmd(pfn, prot));
pfn += PTRS_PER_PTE;
@@ -213,11 +215,14 @@
if (is_kernel_text(addr))
prot = PAGE_KERNEL_EXEC;
+ pages_4k++;
set_pte(pte, pfn_pte(pfn, prot));
}
max_pfn_mapped = pfn;
}
}
+ update_page_count(PG_LEVEL_2M, pages_2m);
+ update_page_count(PG_LEVEL_4K, pages_4k);
}
static inline int page_kills_ppro(unsigned long pagenr)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 819dad9..5e43838 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -312,6 +312,8 @@
static unsigned long __meminit
phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end)
{
+ unsigned long pages = 0;
+
int i = pmd_index(address);
for (; i < PTRS_PER_PMD; i++, address += PMD_SIZE) {
@@ -328,9 +330,11 @@
if (pmd_val(*pmd))
continue;
+ pages++;
set_pte((pte_t *)pmd,
pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
}
+ update_page_count(PG_LEVEL_2M, pages);
return address;
}
@@ -350,6 +354,7 @@
static unsigned long __meminit
phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end)
{
+ unsigned long pages = 0;
unsigned long last_map_addr = end;
int i = pud_index(addr);
@@ -374,6 +379,7 @@
}
if (direct_gbpages) {
+ pages++;
set_pte((pte_t *)pud,
pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
last_map_addr = (addr & PUD_MASK) + PUD_SIZE;
@@ -390,6 +396,7 @@
unmap_low_page(pmd);
}
__flush_tlb_all();
+ update_page_count(PG_LEVEL_1G, pages);
return last_map_addr >> PAGE_SHIFT;
}
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 60bcb5b..668205b 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -34,6 +34,19 @@
unsigned force_split : 1;
};
+static unsigned long direct_pages_count[PG_LEVEL_NUM];
+
+void __meminit update_page_count(int level, unsigned long pages)
+{
+#ifdef CONFIG_PROC_FS
+ unsigned long flags;
+ /* Protect against CPA */
+ spin_lock_irqsave(&pgd_lock, flags);
+ direct_pages_count[level] += pages;
+ spin_unlock_irqrestore(&pgd_lock, flags);
+#endif
+}
+
#ifdef CONFIG_X86_64
static inline unsigned long highmap_start_pfn(void)
@@ -500,6 +513,12 @@
for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc)
set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
+ if (address >= (unsigned long)__va(0) &&
+ address < (unsigned long)__va(max_pfn_mapped << PAGE_SHIFT)) {
+ direct_pages_count[level]--;
+ direct_pages_count[level - 1] += PTRS_PER_PTE;
+ }
+
/*
* Install the new, split up pagetable. Important details here:
*
@@ -1029,6 +1048,22 @@
#endif /* CONFIG_DEBUG_PAGEALLOC */
+#ifdef CONFIG_PROC_FS
+int arch_report_meminfo(char *page)
+{
+ int n;
+ n = sprintf(page, "DirectMap4k: %8lu\n"
+ "DirectMap2M: %8lu\n",
+ direct_pages_count[PG_LEVEL_4K],
+ direct_pages_count[PG_LEVEL_2M]);
+#ifdef CONFIG_X86_64
+ n += sprintf(page + n, "DirectMap1G: %8lu\n",
+ direct_pages_count[PG_LEVEL_1G]);
+#endif
+ return n;
+}
+#endif
+
/*
* The testcases use internal knowledge of the implementation that shouldn't
* be exposed to the rest of the kernel. Include these directly here.
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 7e277f2..15f7bd4 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -123,6 +123,11 @@
return proc_calc_metrics(page, start, off, count, eof, len);
}
+int __attribute__((weak)) arch_report_meminfo(char *page)
+{
+ return 0;
+}
+
static int meminfo_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
@@ -221,6 +226,8 @@
len += hugetlb_report_meminfo(page + len);
+ len += arch_report_meminfo(page + len);
+
return proc_calc_metrics(page, start, off, count, eof, len);
#undef K
}
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 97c271b..111564f 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -369,8 +369,11 @@
PG_LEVEL_4K,
PG_LEVEL_2M,
PG_LEVEL_1G,
+ PG_LEVEL_NUM
};
+void update_page_count(int level, unsigned long pages);
+
/*
* Helper function that returns the kernel pagetable entry controlling
* the virtual address 'address'. NULL means no pagetable entry present.