Messages in this thread Patch in this message | | | Date | Tue, 25 Mar 2008 18:01:19 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH] CPA: Add statistics about state of direct mapping v4 |
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All comments addressed now hopefully.
-Andi
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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 <ak@suse.de> Signed-off-by: Andi Kleen <andi@firstfloor.org>
--- arch/x86/mm/init_32.c | 2 ++ arch/x86/mm/init_64.c | 2 ++ arch/x86/mm/pageattr.c | 24 ++++++++++++++++++++++++ fs/proc/proc_misc.c | 7 +++++++ include/asm-x86/pgtable.h | 3 +++ 5 files changed, 38 insertions(+)
Index: linux/arch/x86/mm/init_64.c =================================================================== --- linux.orig/arch/x86/mm/init_64.c +++ linux/arch/x86/mm/init_64.c @@ -319,6 +319,8 @@ __meminit void early_iounmap(void *addr, 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) { @@ -335,9 +337,11 @@ phys_pmd_init(pmd_t *pmd_page, unsigned 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; } @@ -356,6 +360,7 @@ phys_pmd_update(pud_t *pud, unsigned lon static unsigned long __meminit phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end) { + unsigned long pages = 0; unsigned long true_end = end; int i = pud_index(addr); @@ -380,6 +385,7 @@ phys_pud_init(pud_t *pud_page, unsigned } if (direct_gbpages) { + pages++; set_pte((pte_t *)pud, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE)); true_end = (addr & PUD_MASK) + PUD_SIZE; @@ -397,6 +403,8 @@ phys_pud_init(pud_t *pud_page, unsigned } __flush_tlb_all(); + update_page_count(PG_LEVEL_1G, pages); + return true_end >> PAGE_SHIFT; } Index: linux/arch/x86/mm/pageattr.c =================================================================== --- linux.orig/arch/x86/mm/pageattr.c +++ linux/arch/x86/mm/pageattr.c @@ -31,6 +31,19 @@ struct cpa_data { 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) @@ -499,6 +512,12 @@ static int split_large_page(pte_t *kpte, 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(end_pfn_map << PAGE_SHIFT)) { + direct_pages_count[level]--; + direct_pages_count[level - 1] += PTRS_PER_PTE; + } + /* * Install the new, split up pagetable. Important details here: * @@ -948,6 +967,22 @@ bool kernel_page_present(struct page *pa #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. Index: linux/include/asm-x86/pgtable.h =================================================================== --- linux.orig/include/asm-x86/pgtable.h +++ linux/include/asm-x86/pgtable.h @@ -247,8 +247,11 @@ enum { 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. Index: linux/arch/x86/mm/init_32.c =================================================================== --- linux.orig/arch/x86/mm/init_32.c +++ linux/arch/x86/mm/init_32.c @@ -163,6 +163,7 @@ static void __init kernel_physical_mappi 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; @@ -198,6 +199,7 @@ static void __init kernel_physical_mappi is_kernel_text(addr2)) prot = PAGE_KERNEL_LARGE_EXEC; + pages_2m++; set_pmd(pmd, pfn_pmd(pfn, prot)); pfn += PTRS_PER_PTE; @@ -214,11 +216,14 @@ static void __init kernel_physical_mappi if (is_kernel_text(addr)) prot = PAGE_KERNEL_EXEC; + pages_4k++; set_pte(pte, pfn_pte(pfn, prot)); } end_pfn_map = 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) Index: linux/fs/proc/proc_misc.c =================================================================== --- linux.orig/fs/proc/proc_misc.c +++ linux/fs/proc/proc_misc.c @@ -123,6 +123,11 @@ static int uptime_read_proc(char *page, 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) { @@ -219,6 +224,8 @@ static int meminfo_read_proc(char *page, len += hugetlb_report_meminfo(page + len); + len += arch_report_meminfo(page + len); + return proc_calc_metrics(page, start, off, count, eof, len); #undef K }
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