On 2023/5/11 16:19, HAGIO KAZUHITO(萩尾 一仁) wrote:
On 2023/05/10 20:39, Rongwei Wang wrote:Hi, Kazu As we discussed in previous email, I re-code this patch under x86_64 and arm64 env. The change log as belows. change log: v1->v2: - rename and move zero_paddr and huge_zero_paddr into vm_init(); - simplify fprintf() code block; - support x86_64 arch;Thank you for the update.And if I miss something, please let me know. Thanks, -wrw On 2023/5/10 19:32, Rongwei Wang wrote: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)btw, how can I create this situation seeing zero page easily? I also would like to test the patch.
Here a testcase that I used to allocate zero page:
z.c:
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
unsigned long *zero_data;
void read_only(void)
{
unsigned long i, val, count = 0;
printf("hello\n");
while (count++ < 10) {
for (i=0; i<(4 * 1024 * 1024) / sizeof(unsigned long);
i+=1024) {
val = zero_data[i];
}
}
return;
}
int main(int argc, char *argv[])
{
char c;
zero_data = (unsigned long *)malloc(1024 * 1024 * 4);
if (!zero_data) {
printf("malloc fail: exit\n");
return -1;
}
printf("zero: %lx\n", zero_data);
read_only();
c = getchar();
free(zero_data);
exit(EXIT_SUCCESS);
}
When you test in arm64 with 64k base pagesize, the size of allocating
memory is needed to set more than 512MB.
PTE PHYSICAL FLAGS 160000836e71fc3 836e71000 (VALID|USER|RDONLY|SHARED|AF|NG|PXN|UXN|SPECIAL) VMA START END FLAGS FILE ffff000844f51860 ffff8917c000 ffff8957d000 100073 PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffe001fbb9c40 836e71000 0 0 1 2ffffc000001000 reserveda bit verbose, please replace these with "..."
Your mean comment as below is OK? 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) PTE PHYSICAL FLAGS 60000910c00fc1 910c00000 (VALID|USER|RDONLY|SHARED|AF|NG|PXN|UXN) VMA START END FLAGS FILE ffff0000caa711e0 ffff956a9000 ffff95aaa000 100073 PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffe0023230000 910c00000 0 0 1 6ffffc000010000 head That seems be sensible with this patch.Same as above.Signed-off-by: Rongwei Wang <rongwei.wang@xxxxxxxxxxxxxxxxx> --- arm64.c | 26 +++++++++++++++++--------- defs.h | 6 ++++++ memory.c | 20 ++++++++++++++++++++ x86_64.c | 9 +++++---- 4 files changed, 48 insertions(+), 13 deletions(-) diff --git a/arm64.c b/arm64.c index 56fb841..d70f202 100644 --- a/arm64.c +++ b/arm64.c @@ -419,7 +419,7 @@ arm64_init(int when) /* use machdep parameters */ arm64_calc_phys_offset(); arm64_calc_physvirt_offset(); - + if (CRASHDEBUG(1)) { if (machdep->flags & NEW_VMEMMAP) fprintf(fp, "kimage_voffset: %lx\n", @@ -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..1be5a68 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;Please print these with "help -v", for example, here. node_online_map_len: 16 node_online_map: [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] zero_paddr: 10ef9000 huge_zero_paddr: fffffffffffff000 nr_vm_stat_items: 0 vm_stat_items: (not used)
OK, will do.
}; #define NODES (0x1) @@ -2999,6 +3001,10 @@ 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) != ~0UL && \ + ((paddr) == vt->zero_paddr || \ + (paddr) == vt->huge_zero_paddr))Ah, (paddr) != ~0UL would be unnecessary, if we use ~0UL as the invalid address.
OK, will do.
+ /* * Sparse memory stuff * These must follow the definitions in the kernel mmzone.h diff --git a/memory.c b/memory.c index 0568f18..4ad5959 100644 --- a/memory.c +++ b/memory.c @@ -1208,6 +1208,26 @@ vm_init(void) machdep->memory_size())); vt->paddr_prlen = strlen(buf); + if (kernel_symbol_exists("zero_pfn")) { + ulong zero_pfn; + + vt->zero_paddr = ~0UL;Please move this out of the if block to initialize it even if the symbol does not exist.
OH, that's my fault, will do.
+ 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(); + } + + if (kernel_symbol_exists("huge_zero_pfn")) { + ulong huge_zero_pfn; + + vt->huge_zero_paddr = ~0UL;Same as above.+ if (readmem(symbol_value("huge_zero_pfn"), KVADDR, + &huge_zero_pfn, sizeof(huge_zero_pfn), + "read huge_zero_pfn", QUIET|RETURN_ON_ERROR)) + vt->huge_zero_paddr = huge_zero_pfn << PAGESHIFT();In kernel, huge_zero_pfn is initialized as ~0UL and set to a pfn when get_huge_zero_page() is called. crash> p -x huge_zero_pfn huge_zero_pfn = $4 = 0xffffffffffffffff so if huge_zero_pfn is ~0UL, vt->huge_zero_paddr should not be set.
Good catch.
How about following modification:
+ if (readmem(symbol_value("huge_zero_pfn"), KVADDR,
+ &huge_zero_pfn, sizeof(huge_zero_pfn),
+ "read huge_zero_pfn", QUIET|RETURN_ON_ERROR))
+ vt->huge_zero_paddr = (huge_zero_pfn != ~0UL) ?
(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) 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); }why only for uvtop_level4?
That because I have no idea about xyz_xen_wpt and similar target. In addition, I have no environment to test that, so...
How about doing this when someone need it in these environment? Or I can do it if you think just complete it directly is ok.
Thanks for your time! -wrw
Thanks, Kazu
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