Re: [Crash-utility] [PATCH v4] arm64/x86_64: show zero pfn information when using vtop

Now vtop can not show us the page is zero pfn when PTE or PMD has attached ZERO PAGE. This patch supports show this information directly when using vtop, likes: crash> vtop -c 13674 ffff8917e000 VIRTUAL PHYSICAL ffff8917e000 836e71000 PAGE DIRECTORY: ffff000802f8d000 PGD: ffff000802f8dff8 => 884e29003 PUD: ffff000844e29ff0 => 884e93003 PMD: ffff000844e93240 => 840413003 PTE: ffff000800413bf0 => 160000836e71fc3 PAGE: 836e71000 (ZERO PAGE) ... If huge page found: crash> vtop -c 14538 ffff95800000 VIRTUAL PHYSICAL ffff95800000 910c00000 PAGE DIRECTORY: ffff000801fa0000 PGD: ffff000801fa0ff8 => 884f53003 PUD: ffff000844f53ff0 => 8426cb003 PMD: ffff0008026cb560 => 60000910c00fc1 PAGE: 910c00000 (2MB, ZERO PAGE) ... That seems be sensible with this patch. And there are two points have to be noted for 'ZERO PAGE' label: 1. only supports displaying zero page for THP(except for 1G THP) 2. do not support for the hugetlb cases Signed-off-by: Rongwei Wang <rongwei.wang(a)linux.alibaba.com&gt; --- arm64.c | 24 ++++++++++++++++-------- defs.h | 5 +++++ memory.c | 23 +++++++++++++++++++++++ x86_64.c | 9 +++++---- 4 files changed, 49 insertions(+), 12 deletions(-) diff --git a/arm64.c b/arm64.c index 56fb841..efbdccb 100644 --- a/arm64.c +++ b/arm64.c @@ -1787,7 +1787,8 @@ arm64_vtop_2level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if ((pgd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) { ulong sectionbase = (pgd_val & SECTION_PAGE_MASK_512MB) & PHYS_MASK; if (verbose) { - fprintf(fp, " PAGE: %lx (512MB)\n\n", sectionbase); + fprintf(fp, " PAGE: %lx (512MB%s)\n\n", sectionbase, + IS_ZEROPAGE(sectionbase) ? ", ZERO PAGE" : ""); arm64_translate_pte(pgd_val, 0, 0); } *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_512MB); @@ -1806,7 +1807,8 @@ arm64_vtop_2level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if (pte_val & PTE_VALID) { *paddr = (PAGEBASE(pte_val) & PHYS_MASK) + PAGEOFFSET(vaddr); if (verbose) { - fprintf(fp, " PAGE: %lx\n\n", PAGEBASE(*paddr)); + fprintf(fp, " PAGE: %lx %s\n\n", PAGEBASE(*paddr), + IS_ZEROPAGE(PAGEBASE(*paddr)) ? "(ZERO PAGE)" : ""); arm64_translate_pte(pte_val, 0, 0); } } else { @@ -1859,7 +1861,8 @@ arm64_vtop_3level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if ((pmd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) { ulong sectionbase = PTE_TO_PHYS(pmd_val) & SECTION_PAGE_MASK_512MB; if (verbose) { - fprintf(fp, " PAGE: %lx (512MB)\n\n", sectionbase); + fprintf(fp, " PAGE: %lx (512MB%s)\n\n", sectionbase, + IS_ZEROPAGE(sectionbase) ? ", ZERO PAGE" : ""); arm64_translate_pte(pmd_val, 0, 0); } *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_512MB); @@ -1878,7 +1881,8 @@ arm64_vtop_3level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if (pte_val & PTE_VALID) { *paddr = PTE_TO_PHYS(pte_val) + PAGEOFFSET(vaddr); if (verbose) { - fprintf(fp, " PAGE: %lx\n\n", PAGEBASE(*paddr)); + fprintf(fp, " PAGE: %lx %s\n\n", PAGEBASE(*paddr), + IS_ZEROPAGE(PAGEBASE(*paddr)) ? "(ZERO PAGE)" : ""); arm64_translate_pte(pte_val, 0, 0); } } else { @@ -1940,7 +1944,8 @@ arm64_vtop_3level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if ((pmd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) { ulong sectionbase = (pmd_val & SECTION_PAGE_MASK_2MB) & PHYS_MASK; if (verbose) { - fprintf(fp, " PAGE: %lx (2MB)\n\n", sectionbase); + fprintf(fp, " PAGE: %lx (2MB%s)\n\n", sectionbase, + IS_ZEROPAGE(sectionbase) ? ", ZERO PAGE" : ""); arm64_translate_pte(pmd_val, 0, 0); } *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_2MB); @@ -1959,7 +1964,8 @@ arm64_vtop_3level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if (pte_val & PTE_VALID) { *paddr = (PAGEBASE(pte_val) & PHYS_MASK) + PAGEOFFSET(vaddr); if (verbose) { - fprintf(fp, " PAGE: %lx\n\n", PAGEBASE(*paddr)); + fprintf(fp, " PAGE: %lx %s\n\n", PAGEBASE(*paddr), + IS_ZEROPAGE(PAGEBASE(*paddr)) ? "(ZERO PAGE)" : ""); arm64_translate_pte(pte_val, 0, 0); } } else { @@ -2029,7 +2035,8 @@ arm64_vtop_4level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if ((pmd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) { ulong sectionbase = (pmd_val & SECTION_PAGE_MASK_2MB) & PHYS_MASK; if (verbose) { - fprintf(fp, " PAGE: %lx (2MB)\n\n", sectionbase); + fprintf(fp, " PAGE: %lx (2MB%s)\n\n", sectionbase, + IS_ZEROPAGE(sectionbase) ? ", ZERO PAGE" : ""); arm64_translate_pte(pmd_val, 0, 0); } *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_2MB); @@ -2048,7 +2055,8 @@ arm64_vtop_4level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if (pte_val & PTE_VALID) { *paddr = (PAGEBASE(pte_val) & PHYS_MASK) + PAGEOFFSET(vaddr); if (verbose) { - fprintf(fp, " PAGE: %lx\n\n", PAGEBASE(*paddr)); + fprintf(fp, " PAGE: %lx %s\n\n", PAGEBASE(*paddr), + IS_ZEROPAGE(PAGEBASE(*paddr)) ? "(ZERO PAGE)" : ""); arm64_translate_pte(pte_val, 0, 0); } } else { diff --git a/defs.h b/defs.h index 12ad6aa..a6e4ef3 100644 --- a/defs.h +++ b/defs.h @@ -2618,6 +2618,8 @@ struct vm_table { /* kernel VM-related data */ char *name; } *pageflags_data; ulong max_mem_section_nr; + ulong zero_paddr; + ulong huge_zero_paddr; }; #define NODES (0x1) @@ -2999,6 +3001,9 @@ struct load_module { #define VIRTPAGEBASE(X) (((ulong)(X)) & (ulong)machdep->pagemask) #define PHYSPAGEBASE(X) (((physaddr_t)(X)) & (physaddr_t)machdep->pagemask) +#define IS_ZEROPAGE(paddr) ((paddr) == vt->zero_paddr || \ + (paddr) == vt->huge_zero_paddr) + /* * Sparse memory stuff * These must follow the definitions in the kernel mmzone.h diff --git a/memory.c b/memory.c index 0568f18..d791283 100644 --- a/memory.c +++ b/memory.c @@ -1208,6 +1208,27 @@ vm_init(void) machdep->memory_size())); vt->paddr_prlen = strlen(buf); + vt->zero_paddr = ~0UL; + if (kernel_symbol_exists("zero_pfn")) { + ulong zero_pfn; + + if (readmem(symbol_value("zero_pfn"), KVADDR, + &zero_pfn, sizeof(zero_pfn), + "read zero_pfn", QUIET|RETURN_ON_ERROR)) + vt->zero_paddr = zero_pfn << PAGESHIFT(); + } + + vt->huge_zero_paddr = ~0UL; + if (kernel_symbol_exists("huge_zero_pfn")) { + ulong huge_zero_pfn; + + if (readmem(symbol_value("huge_zero_pfn"), KVADDR, + &huge_zero_pfn, sizeof(huge_zero_pfn), + "read huge_zero_pfn", QUIET|RETURN_ON_ERROR) && + huge_zero_pfn != ~0UL) + vt->huge_zero_paddr = huge_zero_pfn << PAGESHIFT(); + } + if (vt->flags & PERCPU_KMALLOC_V1) vt->dump_kmem_cache = dump_kmem_cache_percpu_v1; else if (vt->flags & PERCPU_KMALLOC_V2) @@ -14063,6 +14084,8 @@ dump_vm_table(int verbose) } else { fprintf(fp, " node_online_map: (unused)\n"); } + fprintf(fp, " zero_paddr: %lx\n", vt->zero_paddr); + fprintf(fp, " huge_zero_paddr: %lx\n", vt->huge_zero_paddr); fprintf(fp, " nr_vm_stat_items: %d\n", vt->nr_vm_stat_items); fprintf(fp, " vm_stat_items: %s", (vt->flags & VM_STAT) ? "\n" : "(not used)\n"); diff --git a/x86_64.c b/x86_64.c index 5019c69..693a08b 100644 --- a/x86_64.c +++ b/x86_64.c @@ -2114,8 +2114,9 @@ x86_64_uvtop_level4(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, in goto no_upage; if (pmd_pte & _PAGE_PSE) { if (verbose) { - fprintf(fp, " PAGE: %lx (2MB)\n\n", - PAGEBASE(pmd_pte) & PHYSICAL_PAGE_MASK); + fprintf(fp, " PAGE: %lx (2MB%s)\n\n", + PAGEBASE(pmd_pte) & PHYSICAL_PAGE_MASK, + IS_ZEROPAGE(PAGEBASE(pmd_pte) & PHYSICAL_PAGE_MASK) ? ", ZERO PAGE" : ""); x86_64_translate_pte(pmd_pte, 0, 0); } @@ -2143,8 +2144,8 @@ x86_64_uvtop_level4(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, in *paddr = (PAGEBASE(pte) & PHYSICAL_PAGE_MASK) + PAGEOFFSET(uvaddr); if (verbose) { - fprintf(fp, " PAGE: %lx\n\n", - PAGEBASE(*paddr) & PHYSICAL_PAGE_MASK); + fprintf(fp, " PAGE: %lx %s\n\n", PAGEBASE(*paddr) & PHYSICAL_PAGE_MASK, + IS_ZEROPAGE(PAGEBASE(*paddr) & PHYSICAL_PAGE_MASK) ? "(ZERO PAGE)" : ""); x86_64_translate_pte(pte, 0, 0); }