On Tue, Sep 24, 2024 at 11:42 AM <devel-request@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Date: Tue, 24 Sep 2024 15:30:00 +1200
From: Tao Liu <ltao@xxxxxxxxxx>
Subject: Re: [PATCH v3] kmem: fix the determination
for slab page
To: lijiang <lijiang@xxxxxxxxxx>
Cc: devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Message-ID:
<CAO7dBbVf-GeGZXs011x3LEf_c=0L7jGq8RRv5QRgsN_MEF2UqQ@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi lianbo & qiwu,
For the v3, LGTM, so ack.
Applied:
Thanks
Lianbo
Thanks,
Tao Liu
On Fri, Sep 20, 2024 at 6:55 PM lijiang <lijiang@xxxxxxxxxx> wrote:
>
> On Fri, Sep 20, 2024 at 9:30 AM <devel-request@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> Date: Fri, 20 Sep 2024 01:28:32 -0000
>> From: qiwu.chen@xxxxxxxxxxxxx
>> Subject: [PATCH v3] kmem: fix the determination for
>> slab page
>> To: devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx
>> Message-ID: <20240920012832.29184.28326@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset="utf-8"
>>
>> The determination for a slab page has changed due to changing
>> PG_slab from a page flag to a page type since kernel commit
>> 46df8e73a4a3.
>>
>> Before apply this patch:
>> crash> kmem -s ffff000002aa4100
>> kmem: address is not allocated in slab subsystem: ffff000002aa4100
>>
>> After apply this patch:
>> crash> kmem -s ffff000002aa4100
>> CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME
>> ffff00000140f900 4096 94 126 18 32k task_struct
>> SLAB MEMORY NODE TOTAL ALLOCATED FREE
>> fffffdffc00aa800 ffff000002aa0000 0 7 5 2
>> FREE / [ALLOCATED]
>> [ffff000002aa4100]
>>
>> Signed-off-by: qiwu.chen <qiwu.chen@xxxxxxxxxxxxx>
>> ---
>> defs.h | 7 ++++++
>> memory.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++---------
>> symbols.c | 2 ++
>> 3 files changed, 66 insertions(+), 11 deletions(-)
>>
>
> Thank you for the update, qiwu.
>
> I have no other issues, for the v3: Ack
>
> Thanks
> Lianbo
>
>>
>> diff --git a/defs.h b/defs.h
>> index 2231cb6..e2a9278 100644
>> --- a/defs.h
>> +++ b/defs.h
>> @@ -2243,6 +2243,7 @@ struct offset_table { /* stash of commonly-used offsets */
>> long vmap_node_busy;
>> long rb_list_head;
>> long file_f_inode;
>> + long page_page_type;
>> };
>>
>> struct size_table { /* stash of commonly-used sizes */
>> @@ -2651,6 +2652,7 @@ struct vm_table { /* kernel VM-related data */
>> ulong max_mem_section_nr;
>> ulong zero_paddr;
>> ulong huge_zero_paddr;
>> + uint page_type_base;
>> };
>>
>> #define NODES (0x1)
>> @@ -2684,6 +2686,11 @@ struct vm_table { /* kernel VM-related data */
>> #define SLAB_CPU_CACHE (0x10000000)
>> #define SLAB_ROOT_CACHES (0x20000000)
>> #define USE_VMAP_NODES (0x40000000)
>> +/*
>> + * The SLAB_PAGEFLAGS flag is introduced to detect the change of
>> + * PG_slab's type from a page flag to a page type.
>> + */
>> +#define SLAB_PAGEFLAGS (0x80000000)
>>
>> #define IS_FLATMEM() (vt->flags & FLATMEM)
>> #define IS_DISCONTIGMEM() (vt->flags & DISCONTIGMEM)
>> diff --git a/memory.c b/memory.c
>> index 967a9cf..8befe8c 100644
>> --- a/memory.c
>> +++ b/memory.c
>> @@ -351,6 +351,43 @@ static ulong handle_each_vm_area(struct handle_each_vm_area_args *);
>>
>> static ulong DISPLAY_DEFAULT;
>>
>> +/*
>> + * Before kernel commit ff202303c398e, the value is defined as a macro, so copy it here;
>> + * After this commit, the value is defined as an enum, which can be evaluated at runtime.
>> + */
>> +#define PAGE_TYPE_BASE 0xf0000000
>> +#define PageType(page_type, flag) \
>> + ((page_type & (vt->page_type_base | flag)) == vt->page_type_base)
>> +
>> +static void page_type_init(void)
>> +{
>> + if (!enumerator_value("PAGE_TYPE_BASE", (long *)&vt->page_type_base))
>> + vt->page_type_base = PAGE_TYPE_BASE;
>> +}
>> +
>> +/*
>> + * The PG_slab's type has changed from a page flag to a page type
>> + * since kernel commit 46df8e73a4a3.
>> + */
>> +static bool page_slab(ulong page, ulong flags)
>> +{
>> + if (vt->flags & SLAB_PAGEFLAGS) {
>> + if ((flags >> vt->PG_slab) & 1)
>> + return TRUE;
>> + }
>> +
>> + if (VALID_MEMBER(page_page_type)) {
>> + uint page_type;
>> +
>> + readmem(page+OFFSET(page_page_type), KVADDR, &page_type,
>> + sizeof(page_type), "page_type", FAULT_ON_ERROR);
>> + if (PageType(page_type, (uint)vt->PG_slab))
>> + return TRUE;
>> + }
>> +
>> + return FALSE;
>> +}
>> +
>> /*
>> * Verify that the sizeof the primitive types are reasonable.
>> */
>> @@ -504,6 +541,7 @@ vm_init(void)
>> ANON_MEMBER_OFFSET_INIT(page_compound_head, "page", "compound_head");
>> MEMBER_OFFSET_INIT(page_private, "page", "private");
>> MEMBER_OFFSET_INIT(page_freelist, "page", "freelist");
>> + MEMBER_OFFSET_INIT(page_page_type, "page", "page_type");
>>
>> MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
>>
>> @@ -1278,6 +1316,8 @@ vm_init(void)
>>
>> page_flags_init();
>>
>> + page_type_init();
>> +
>> rss_page_types_init();
>>
>> vt->flags |= VM_INIT;
>> @@ -5931,7 +5971,7 @@ dump_mem_map_SPARSEMEM(struct meminfo *mi)
>> if ((flags >> v22_PG_Slab) & 1)
>> slabs++;
>> } else if (vt->PG_slab) {
>> - if ((flags >> vt->PG_slab) & 1)
>> + if (page_slab(pp, flags))
>> slabs++;
>> } else {
>> if ((flags >> v24_PG_slab) & 1)
>> @@ -6381,7 +6421,7 @@ dump_mem_map(struct meminfo *mi)
>> if ((flags >> v22_PG_Slab) & 1)
>> slabs++;
>> } else if (vt->PG_slab) {
>> - if ((flags >> vt->PG_slab) & 1)
>> + if (page_slab(pp, flags))
>> slabs++;
>> } else {
>> if ((flags >> v24_PG_slab) & 1)
>> @@ -6694,7 +6734,6 @@ dump_hstates()
>> FREEBUF(hstate);
>> }
>>
>> -
>> static void
>> page_flags_init(void)
>> {
>> @@ -6775,6 +6814,9 @@ page_flags_init_from_pageflag_names(void)
>> vt->pageflags_data[i].name = nameptr;
>> vt->pageflags_data[i].mask = mask;
>>
>> + if (!strncmp(nameptr, "slab", 4))
>> + vt->flags |= SLAB_PAGEFLAGS;
>> +
>> if (CRASHDEBUG(1)) {
>> fprintf(fp, " %08lx %s\n",
>> vt->pageflags_data[i].mask,
>> @@ -6835,8 +6877,9 @@ page_flags_init_from_pageflags_enum(void)
>> }
>> strcpy(nameptr, arglist[0] + strlen("PG_"));
>> vt->pageflags_data[p].name = nameptr;
>> - vt->pageflags_data[p].mask = 1 << atoi(arglist[2]);
>> -
>> + vt->pageflags_data[p].mask = 1 << atoi(arglist[2]);
>> + if (!strncmp(nameptr, "slab", 4))
>> + vt->flags |= SLAB_PAGEFLAGS;
>> p++;
>> }
>> } else
>> @@ -9736,14 +9779,14 @@ vaddr_to_kmem_cache(ulong vaddr, char *buf, int verbose)
>> readmem(page+OFFSET(page_flags), KVADDR,
>> &page_flags, sizeof(ulong), "page.flags",
>> FAULT_ON_ERROR);
>> - if (!(page_flags & (1 << vt->PG_slab))) {
>> + if (!page_slab(page, page_flags)) {
>> if (((vt->flags & KMALLOC_SLUB) || VALID_MEMBER(page_compound_head)) ||
>> ((vt->flags & KMALLOC_COMMON) &&
>> VALID_MEMBER(page_slab) && VALID_MEMBER(page_first_page))) {
>> readmem(compound_head(page)+OFFSET(page_flags), KVADDR,
>> &page_flags, sizeof(ulong), "page.flags",
>> FAULT_ON_ERROR);
>> - if (!(page_flags & (1 << vt->PG_slab)))
>> + if (!page_slab(compound_head(page), page_flags))
>> return NULL;
>> } else
>> return NULL;
>> @@ -14108,6 +14151,8 @@ dump_vm_table(int verbose)
>> fprintf(fp, "%sNODELISTS_IS_PTR", others++ ? "|" : "");\
>> if (vt->flags & VM_INIT)
>> fprintf(fp, "%sVM_INIT", others++ ? "|" : "");\
>> + if (vt->flags & SLAB_PAGEFLAGS)
>> + fprintf(fp, "%sSLAB_PAGEFLAGS", others++ ? "|" : "");\
>>
>> fprintf(fp, ")\n");
>> if (vt->kernel_pgd[0] == vt->kernel_pgd[1])
>> @@ -14237,6 +14282,7 @@ dump_vm_table(int verbose)
>> vt->pageflags_data[i].mask,
>> vt->pageflags_data[i].name);
>> }
>> + fprintf(fp, " page_type_base: %x\n", vt->page_type_base);
>>
>> dump_vma_cache(VERBOSE);
>> }
>> @@ -20195,7 +20241,7 @@ char *
>> is_slab_page(struct meminfo *si, char *buf)
>> {
>> int i, cnt;
>> - ulong page_slab, page_flags, name;
>> + ulong pg_slab, page_flags, name;
>> ulong *cache_list;
>> char *retval;
>>
>> @@ -20210,11 +20256,11 @@ is_slab_page(struct meminfo *si, char *buf)
>> RETURN_ON_ERROR|QUIET))
>> return NULL;
>>
>> - if (!(page_flags & (1 << vt->PG_slab)))
>> + if (!page_slab(si->spec_addr, page_flags))
>> return NULL;
>>
>> if (!readmem(si->spec_addr + OFFSET(page_slab), KVADDR,
>> - &page_slab, sizeof(ulong), "page.slab",
>> + &pg_slab, sizeof(ulong), "page.slab",
>> RETURN_ON_ERROR|QUIET))
>> return NULL;
>>
>> @@ -20222,7 +20268,7 @@ is_slab_page(struct meminfo *si, char *buf)
>> cnt = get_kmem_cache_list(&cache_list);
>>
>> for (i = 0; i < cnt; i++) {
>> - if (page_slab == cache_list[i]) {
>> + if (pg_slab == cache_list[i]) {
>> if (!readmem(cache_list[i] + OFFSET(kmem_cache_name),
>> KVADDR, &name, sizeof(char *),
>> "kmem_cache.name", QUIET|RETURN_ON_ERROR))
>> diff --git a/symbols.c b/symbols.c
>> index 69a1fbb..014cd29 100644
>> --- a/symbols.c
>> +++ b/symbols.c
>> @@ -10339,6 +10339,8 @@ dump_offset_table(char *spec, ulong makestruct)
>> fprintf(fp, " page_compound_head: %ld\n",
>> OFFSET(page_compound_head));
>> fprintf(fp, " page_private: %ld\n", OFFSET(page_private));
>> + fprintf(fp, " page_page_type: %ld\n",
>> + OFFSET(page_page_type));
>>
>> fprintf(fp, " trace_print_flags_mask: %ld\n",
>> OFFSET(trace_print_flags_mask));
>> --
>> 2.25.1
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