[Crash-utility] [PATCH RFC] Add "kmem -r" to display accumulated slab statistics like /proc/slabinfo
Dave Anderson
anderson at redhat.com
Thu Aug 23 20:31:26 UTC 2018
----- Original Message -----
> Nowadays, the "kmem -s" output can become very long vertically too,
> due to the memcg kmem caches. It look like the longer a system has
> run, the longer it becomes.
>
> crash> kmem -s | wc -l
> 19855
>
> On the other hand, since /proc/slabinfo accumulates the values of
> each slab_root_caches and its children, it's still short relatively.
> And I think there are many cases that support folks want to see the
> accumulated values like /proc/slabinfo from vmcore, in order to
> grasp the overview of slab activity quickly.
>
> We can use something like the attached script to accumulate them,
> but I believe it would be more useful to implement it in crash.
>
> This patch introduces the "kmem -r" option to imitate /proc/slabinfo,
> but it is limited to CONFIG_SLUB for now.
And it looks like it's limited to Linux 4.11 and later, correct?
Thanks,
Dave
>
> I tested this patch with the kmem-s2r.awk script:
>
> crash> kmem -s | awk -f kmem-s2r.awk > kmem-s2r.txt
> crash> kmem -r > kmem-r.txt
>
> # diff -u kmem-s2r.txt kmem-r.txt
>
> Supported:
> crash> kmem -r
> crash> kmem -r list
> crash> kmem -r <slab name>
>
> Signed-off-by: Kazuhito Hagio <k-hagio at ab.jp.nec.com>
> ---
> defs.h | 5 ++
> help.c | 10 +--
> memory.c | 219
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
> symbols.c | 9 +++
> 4 files changed, 220 insertions(+), 23 deletions(-)
>
> diff --git a/defs.h b/defs.h
> index 6fdb478..8687ff1 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -2032,6 +2032,10 @@ struct offset_table { /* stash of
> commonly-used offsets */
> long bpf_prog_aux_user;
> long user_struct_uid;
> long idr_cur;
> + long kmem_cache_memcg_params;
> + long memcg_cache_params___root_caches_node;
> + long memcg_cache_params_children;
> + long memcg_cache_params_children_node;
> };
>
> struct size_table { /* stash of commonly-used sizes */
> @@ -2438,6 +2442,7 @@ struct vm_table { /* kernel VM-related
> data */
> #define PAGEFLAGS (0x4000000)
> #define SLAB_OVERLOAD_PAGE (0x8000000)
> #define SLAB_CPU_CACHE (0x10000000)
> +#define SLAB_ROOT_CACHES (0x20000000)
>
> #define IS_FLATMEM() (vt->flags & FLATMEM)
> #define IS_DISCONTIGMEM() (vt->flags & DISCONTIGMEM)
> diff --git a/help.c b/help.c
> index aeeb056..ee8b999 100644
> --- a/help.c
> +++ b/help.c
> @@ -6448,7 +6448,7 @@ char *help_kmem[] = {
> "kmem",
> "kernel memory",
> "[-f|-F|-c|-C|-i|-v|-V|-n|-z|-o|-h] [-p | -m member[,member]]\n"
> -" [[-s|-S] [slab] [-I slab[,slab]]] [-g [flags]] [[-P] address]]",
> +" [[-s|-S|-r] [slab] [-I slab[,slab]]] [-g [flags]] [[-P] address]]",
> " This command displays information about the use of kernel memory.\n",
> " -f displays the contents of the system free memory headers.",
> " also verifies that the page count equals nr_free_pages.",
> @@ -6490,10 +6490,12 @@ char *help_kmem[] = {
> " slab data for each per-cpu slab is displayed, along with the",
> " address of each kmem_cache_node, its count of full and
> partial",
> " slabs, and a list of all tracked slabs.",
> -" slab when used with -s or -S, limits the command to only the slab
> cache",
> -" of name \"slab\". If the slab argument is \"list\", then",
> +" -r displays accumulated kmalloc() slab data of each
> slab_root_caches",
> +" and its children. Available only if CONFIG_SLUB for now.",
> +" slab when used with -s, -S or -r, limits the command to only the
> slab",
> +" cache of name \"slab\". If the slab argument is \"list\",
> then",
> " all slab cache names and addresses are listed.",
> -" -I slab when used with -s or -S, one or more slab cache names in a",
> +" -I slab when used with -s, -S or -r, one or more slab cache names in
> a",
> " comma-separated list may be specified as slab caches to
> ignore.",
> " -g displays the enumerator value of all bits in the page
> structure's",
> " \"flags\" field.",
> diff --git a/memory.c b/memory.c
> index e02ba68..1501b21 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -167,12 +167,12 @@ static int kmem_cache_downsize(void);
> static int ignore_cache(struct meminfo *, char *);
> static char *is_kmem_cache_addr(ulong, char *);
> static char *is_kmem_cache_addr_common(ulong, char *);
> -static void kmem_cache_list(void);
> +static void kmem_cache_list(struct meminfo *);
> static void dump_kmem_cache(struct meminfo *);
> static void dump_kmem_cache_percpu_v1(struct meminfo *);
> static void dump_kmem_cache_percpu_v2(struct meminfo *);
> static void dump_kmem_cache_slub(struct meminfo *);
> -static void kmem_cache_list_common(void);
> +static void kmem_cache_list_common(struct meminfo *);
> static ulong get_cpu_slab_ptr(struct meminfo *, int, ulong *);
> static unsigned int oo_order(ulong);
> static unsigned int oo_objects(ulong);
> @@ -276,6 +276,8 @@ static int generic_read_dumpfile(ulonglong, void *, long,
> char *, ulong);
> static int generic_write_dumpfile(ulonglong, void *, long, char *, ulong);
> static int page_to_nid(ulong);
> static int get_kmem_cache_list(ulong **);
> +static int get_kmem_cache_root_list(ulong **);
> +static int get_kmem_cache_child_list(ulong **, ulong);
> static int get_kmem_cache_slub_data(long, struct meminfo *);
> static ulong compound_head(ulong);
> static long count_partial(ulong, struct meminfo *, ulong *);
> @@ -815,6 +817,23 @@ vm_init(void)
> "kmem_slab_s", "s_magic");
> }
>
> + if (kernel_symbol_exists("slab_root_caches")) {
> + MEMBER_OFFSET_INIT(kmem_cache_memcg_params,
> + "kmem_cache", "memcg_params");
> + MEMBER_OFFSET_INIT(memcg_cache_params___root_caches_node,
> + "memcg_cache_params", "__root_caches_node");
> + MEMBER_OFFSET_INIT(memcg_cache_params_children,
> + "memcg_cache_params", "children");
> + MEMBER_OFFSET_INIT(memcg_cache_params_children_node,
> + "memcg_cache_params", "children_node");
> +
> + if (VALID_MEMBER(kmem_cache_memcg_params)
> + && VALID_MEMBER(memcg_cache_params___root_caches_node)
> + && VALID_MEMBER(memcg_cache_params_children)
> + && VALID_MEMBER(memcg_cache_params_children_node))
> + vt->flags |= SLAB_ROOT_CACHES;
> + }
> +
> if (!kt->kernel_NR_CPUS) {
> if (enumerator_value("WORK_CPU_UNBOUND", (long *)&value1))
> kt->kernel_NR_CPUS = (int)value1;
> @@ -4713,6 +4732,7 @@ get_task_mem_usage(ulong task, struct task_mem_usage
> *tm)
> #define SLAB_OVERLOAD_PAGE_PTR (ADDRESS_SPECIFIED << 24)
> #define SLAB_BITFIELD (ADDRESS_SPECIFIED << 25)
> #define SLAB_GATHER_FAILURE (ADDRESS_SPECIFIED << 26)
> +#define GET_SLAB_ROOT_CACHES (ADDRESS_SPECIFIED << 27)
>
> #define GET_ALL \
> (GET_SHARED_PAGES|GET_TOTALRAM_PAGES|GET_BUFFERS_PAGES|GET_SLAB_PAGES)
> @@ -4724,6 +4744,7 @@ cmd_kmem(void)
> int c;
> int sflag, Sflag, pflag, fflag, Fflag, vflag, zflag, oflag, gflag;
> int nflag, cflag, Cflag, iflag, lflag, Lflag, Pflag, Vflag, hflag;
> + int rflag;
> struct meminfo meminfo;
> ulonglong value[MAXARGS];
> char buf[BUFSIZE];
> @@ -4733,13 +4754,13 @@ cmd_kmem(void)
> spec_addr = 0;
> sflag = Sflag = pflag = fflag = Fflag = Pflag = zflag = oflag = 0;
> vflag = Cflag = cflag = iflag = nflag = lflag = Lflag = Vflag = 0;
> - gflag = hflag = 0;
> + gflag = hflag = rflag = 0;
> escape = FALSE;
> BZERO(&meminfo, sizeof(struct meminfo));
> BZERO(&value[0], sizeof(ulonglong)*MAXARGS);
> pc->curcmd_flags &= ~HEADER_PRINTED;
>
> - while ((c = getopt(argcnt, args, "gI:sSFfm:pvczCinl:L:PVoh")) !=
> EOF) {
> + while ((c = getopt(argcnt, args, "gI:sSrFfm:pvczCinl:L:PVoh")) !=
> EOF) {
> switch(c)
> {
> case 'V':
> @@ -4775,11 +4796,15 @@ cmd_kmem(void)
> break;
>
> case 's':
> - sflag = 1; Sflag = 0;
> + sflag = 1; Sflag = rflag = 0;
> break;
>
> case 'S':
> - Sflag = 1; sflag = 0;
> + Sflag = 1; sflag = rflag = 0;
> + break;
> +
> + case 'r':
> + rflag = 1; sflag = Sflag = 0;
> break;
>
> case 'F':
> @@ -4859,12 +4884,13 @@ cmd_kmem(void)
> cmd_usage(pc->curcmd, SYNOPSIS);
>
> if ((sflag + Sflag + pflag + fflag + Fflag + Vflag + oflag +
> - vflag + Cflag + cflag + iflag + lflag + Lflag + gflag + hflag) >
> 1) {
> + vflag + Cflag + cflag + iflag + lflag + Lflag + gflag +
> + hflag + rflag) > 1) {
> error(INFO, "only one flag allowed!\n");
> cmd_usage(pc->curcmd, SYNOPSIS);
> }
>
> - if (sflag || Sflag || !(vt->flags & KMEM_CACHE_INIT))
> + if (sflag || Sflag || rflag || !(vt->flags & KMEM_CACHE_INIT))
> kmem_cache_init();
>
> while (args[optind]) {
> @@ -4881,7 +4907,7 @@ cmd_kmem(void)
> escape = TRUE;
> } else
> meminfo.reqname = args[optind];
> - if (!sflag && !Sflag)
> + if (!sflag && !Sflag && !rflag)
> cmd_usage(pc->curcmd, SYNOPSIS);
> }
>
> @@ -4994,7 +5020,7 @@ cmd_kmem(void)
> * no value arguments allowed!
> */
> if (zflag || nflag || iflag || Fflag || Cflag || Lflag ||
> - Vflag || oflag || hflag) {
> + Vflag || oflag || hflag || rflag) {
> error(INFO,
> "no address arguments allowed with this option\n");
> cmd_usage(pc->curcmd, SYNOPSIS);
> @@ -5030,9 +5056,17 @@ cmd_kmem(void)
> if (hflag == 1)
> dump_hstates();
>
> - if (sflag == 1) {
> + if (sflag == 1 || rflag == 1) {
> + if (rflag) {
> + if (!((vt->flags & KMALLOC_SLUB)
> + && (vt->flags & SLAB_ROOT_CACHES)))
> + error(FATAL,
> + "-r option doesn't support this kernel\n");
> +
> + meminfo.flags = GET_SLAB_ROOT_CACHES;
> + }
> if (!escape && STREQ(meminfo.reqname, "list"))
> - kmem_cache_list();
> + kmem_cache_list(&meminfo);
> else if (vt->flags & KMEM_CACHE_UNAVAIL)
> error(FATAL,
> "kmem cache slab subsystem not available\n");
> @@ -5042,7 +5076,7 @@ cmd_kmem(void)
>
> if (Sflag == 1) {
> if (STREQ(meminfo.reqname, "list"))
> - kmem_cache_list();
> + kmem_cache_list(&meminfo);
> else if (vt->flags & KMEM_CACHE_UNAVAIL)
> error(FATAL,
> "kmem cache slab subsystem not available\n");
> @@ -5092,7 +5126,8 @@ cmd_kmem(void)
>
> if (!(sflag + Sflag + pflag + fflag + Fflag + vflag +
> Vflag + zflag + oflag + cflag + Cflag + iflag +
> - nflag + lflag + Lflag + gflag + hflag + meminfo.calls))
> + nflag + lflag + Lflag + gflag + hflag + rflag +
> + meminfo.calls))
> cmd_usage(pc->curcmd, SYNOPSIS);
>
> }
> @@ -9117,7 +9152,7 @@ is_kmem_cache_addr(ulong vaddr, char *kbuf)
> * dumps all slab cache names and their addresses.
> */
> static void
> -kmem_cache_list(void)
> +kmem_cache_list(struct meminfo *mi)
> {
> ulong cache, cache_cache, name;
> long next_offset, name_offset;
> @@ -9132,7 +9167,7 @@ kmem_cache_list(void)
> }
>
> if (vt->flags & (KMALLOC_SLUB|KMALLOC_COMMON)) {
> - kmem_cache_list_common();
> + kmem_cache_list_common(mi);
> return;
> }
>
> @@ -13564,6 +13599,8 @@ dump_vm_table(int verbose)
> fprintf(fp, "%sSLAB_OVERLOAD_PAGE", others++ ? "|" : "");\
> if (vt->flags & SLAB_CPU_CACHE)
> fprintf(fp, "%sSLAB_CPU_CACHE", others++ ? "|" : "");\
> + if (vt->flags & SLAB_ROOT_CACHES)
> + fprintf(fp, "%sSLAB_ROOT_CACHES", others++ ? "|" : "");\
> if (vt->flags & USE_VMAP_AREA)
> fprintf(fp, "%sUSE_VMAP_AREA", others++ ? "|" : "");\
> if (vt->flags & CONFIG_NUMA)
> @@ -18044,14 +18081,17 @@ kmem_cache_init_slub(void)
> }
>
> static void
> -kmem_cache_list_common(void)
> +kmem_cache_list_common(struct meminfo *mi)
> {
> int i, cnt;
> ulong *cache_list;
> ulong name;
> char buf[BUFSIZE];
>
> - cnt = get_kmem_cache_list(&cache_list);
> + if (mi->flags & GET_SLAB_ROOT_CACHES)
> + cnt = get_kmem_cache_root_list(&cache_list);
> + else
> + cnt = get_kmem_cache_list(&cache_list);
>
> for (i = 0; i < cnt; i++) {
> fprintf(fp, "%lx ", cache_list[i]);
> @@ -18087,7 +18127,11 @@ dump_kmem_cache_slub(struct meminfo *si)
> }
>
> order = objects = 0;
> - si->cache_count = get_kmem_cache_list(&si->cache_list);
> + if (si->flags & GET_SLAB_ROOT_CACHES)
> + si->cache_count = get_kmem_cache_root_list(&si->cache_list);
> + else
> + si->cache_count = get_kmem_cache_list(&si->cache_list);
> +
> si->cache_buf = GETBUF(SIZE(kmem_cache));
>
> if (VALID_MEMBER(page_objects) &&
> @@ -18168,6 +18212,79 @@ dump_kmem_cache_slub(struct meminfo *si)
> !get_kmem_cache_slub_data(GET_SLUB_OBJECTS, si))
> si->flags |= SLAB_GATHER_FAILURE;
>
> + /* accumulate children's slabinfo */
> + if (si->flags & GET_SLAB_ROOT_CACHES) {
> + struct meminfo *mi;
> + int j;
> + char buf2[BUFSIZE];
> +
> + mi = (struct meminfo *)GETBUF(sizeof(struct meminfo));
> + memcpy(mi, si, sizeof(struct meminfo));
> +
> + mi->cache_count = get_kmem_cache_child_list(&mi->cache_list,
> + si->cache_list[i]);
> +
> + if (!mi->cache_count)
> + goto no_children;
> +
> + mi->cache_buf = GETBUF(SIZE(kmem_cache));
> +
> + for (j = 0; j < mi->cache_count; j++) {
> + BZERO(mi->cache_buf, SIZE(kmem_cache));
> + if (!readmem(mi->cache_list[j], KVADDR, mi->cache_buf,
> + SIZE(kmem_cache), "kmem_cache buffer",
> + RETURN_ON_ERROR|RETURN_PARTIAL))
> + continue;
> +
> + name = ULONG(mi->cache_buf + OFFSET(kmem_cache_name));
> + if (!read_string(name, buf2, BUFSIZE-1))
> + sprintf(buf2, "(unknown)");
> +
> + objsize = UINT(mi->cache_buf + OFFSET(kmem_cache_objsize));
> + size = UINT(mi->cache_buf + OFFSET(kmem_cache_size));
> + offset = UINT(mi->cache_buf + OFFSET(kmem_cache_offset));
> + if (VALID_MEMBER(kmem_cache_objects)) {
> + objects = UINT(mi->cache_buf +
> + OFFSET(kmem_cache_objects));
> + order = UINT(mi->cache_buf + OFFSET(kmem_cache_order));
> + } else if (VALID_MEMBER(kmem_cache_oo)) {
> + oo = ULONG(mi->cache_buf + OFFSET(kmem_cache_oo));
> + objects = oo_objects(oo);
> + order = oo_order(oo);
> + } else
> + error(FATAL, "cannot determine "
> + "kmem_cache objects/order values\n");
> +
> + mi->cache = mi->cache_list[j];
> + mi->curname = buf2;
> + mi->objsize = objsize;
> + mi->size = size;
> + mi->objects = objects;
> + mi->slabsize = (PAGESIZE() << order);
> + mi->inuse = mi->num_slabs = 0;
> + mi->slab_offset = offset;
> + mi->random = VALID_MEMBER(kmem_cache_random) ?
> + ULONG(mi->cache_buf + OFFSET(kmem_cache_random)) : 0;
> +
> + if (!get_kmem_cache_slub_data(GET_SLUB_SLABS, mi) ||
> + !get_kmem_cache_slub_data(GET_SLUB_OBJECTS, mi)) {
> + si->flags |= SLAB_GATHER_FAILURE;
> + continue;
> + }
> +
> + si->inuse += mi->inuse;
> + si->free += mi->free;
> + si->num_slabs += mi->num_slabs;
> +
> + if (CRASHDEBUG(1))
> + dump_kmem_cache_info(mi);
> + }
> + FREEBUF(mi->cache_buf);
> + FREEBUF(mi->cache_list);
> +no_children:
> + FREEBUF(mi);
> + }
> +
> DUMP_KMEM_CACHE_INFO();
>
> if (si->flags & SLAB_GATHER_FAILURE) {
> @@ -18964,6 +19081,70 @@ get_kmem_cache_list(ulong **cache_buf)
> return cnt;
> }
>
> +static int
> +get_kmem_cache_root_list(ulong **cache_buf)
> +{
> + int cnt;
> + ulong vaddr;
> + struct list_data list_data, *ld;
> +
> + get_symbol_data("slab_root_caches", sizeof(void *), &vaddr);
> +
> + ld = &list_data;
> + BZERO(ld, sizeof(struct list_data));
> + ld->flags |= LIST_ALLOCATE;
> + ld->start = vaddr;
> + ld->list_head_offset = OFFSET(kmem_cache_memcg_params)
> + + OFFSET(memcg_cache_params___root_caches_node);
> + ld->end = symbol_value("slab_root_caches");
> + if (CRASHDEBUG(3))
> + ld->flags |= VERBOSE;
> +
> + cnt = do_list(ld);
> + *cache_buf = ld->list_ptr;
> +
> + return cnt;
> +}
> +
> +static int
> +get_kmem_cache_child_list(ulong **cache_buf, ulong root)
> +{
> + int cnt;
> + ulong vaddr, children;
> + struct list_data list_data, *ld;
> +
> + children = root + OFFSET(kmem_cache_memcg_params)
> + + OFFSET(memcg_cache_params_children);
> +
> + readmem(children, KVADDR, &vaddr, sizeof(ulong),
> + "kmem_cache.memcg_params.children",
> + FAULT_ON_ERROR);
> +
> + /*
> + * When no children, since there is the difference of offset
> + * of children list between root and child, do_list returns
> + * an incorrect cache_buf[0]. So we determine wheather it has
> + * children or not with the value of list_head.next.
> + */
> + if (children == vaddr)
> + return 0;
> +
> + ld = &list_data;
> + BZERO(ld, sizeof(struct list_data));
> + ld->flags |= LIST_ALLOCATE;
> + ld->start = vaddr;
> + ld->list_head_offset =
> + OFFSET(kmem_cache_memcg_params)
> + + OFFSET(memcg_cache_params_children_node);
> + ld->end = children;
> + if (CRASHDEBUG(3))
> + ld->flags |= VERBOSE;
> +
> + cnt = do_list(ld);
> + *cache_buf = ld->list_ptr;
> +
> + return cnt;
> +}
>
> /*
> * Get the address of the head page of a compound page.
> diff --git a/symbols.c b/symbols.c
> index bee60ba..2e6713a 100644
> --- a/symbols.c
> +++ b/symbols.c
> @@ -9451,6 +9451,15 @@ dump_offset_table(char *spec, ulong makestruct)
> fprintf(fp, " kmem_cache_flags: %ld\n",
> OFFSET(kmem_cache_flags));
>
> + fprintf(fp, " kmem_cache_memcg_params: %ld\n",
> + OFFSET(kmem_cache_memcg_params));
> + fprintf(fp, "memcg_cache_params___root_caches_node: %ld\n",
> + OFFSET(memcg_cache_params___root_caches_node));
> + fprintf(fp, " memcg_cache_params_children: %ld\n",
> + OFFSET(memcg_cache_params_children));
> + fprintf(fp, " memcg_cache_params_children_node: %ld\n",
> + OFFSET(memcg_cache_params_children_node));
> +
> fprintf(fp, " net_device_next: %ld\n",
> OFFSET(net_device_next));
> fprintf(fp, " net_device_name: %ld\n",
> --
> 1.8.3.1
>
> --
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> Crash-utility at redhat.com
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