[Crash-utility] [PATCH] kmem: Add support to -S option to specify a range of CPU-specific slab data
Aaron Tomlin
atomlin at redhat.com
Thu Jul 1 19:53:56 UTC 2021
With this patch, it is now possible for one to explicitly specify a range
of CPU-specific slab data to list. For example:
Note: This is only applicable to a Linux kernel with Kconfig
CONFIG_SLUB enabled. The optional argument GNU extension
for getopt(3) is utilised; and, the CPU range must be
specified as expected
crash> kmem -S=1,4 kmalloc-512
CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME
ffff8d3f07c06c00 512 1916 3680 115 16k kmalloc-512
CPU 1 KMEM_CACHE_CPU:
ffff8d461fa6f140
CPU 1 SLAB:
SLAB MEMORY NODE TOTAL ALLOCATED FREE
fffff540df7c4000 ffff8d45df100000 0 32 8 24
FREE / [ALLOCATED]
ffff8d45df100000 (cpu 1 cache)
[ffff8d45df100200]
ffff8d45df100400 (cpu 1 cache)
[ffff8d45df100600]
ffff8d45df100800 (cpu 1 cache)
ffff8d45df100a00 (cpu 1 cache)
ffff8d45df100c00 (cpu 1 cache)
ffff8d45df100e00 (cpu 1 cache)
ffff8d45df101000 (cpu 1 cache)
[ffff8d45df101200]
...skipped ...
CPU 4 KMEM_CACHE_CPU:
ffff8d461fb2f140
CPU 4 SLAB:
SLAB MEMORY NODE TOTAL ALLOCATED FREE
fffff540dfde3800 ffff8d45f78e0000 0 32 8 24
FREE / [ALLOCATED]
[ffff8d45f78e0000]
ffff8d45f78e0200 (cpu 4 cache)
ffff8d45f78e0400 (cpu 4 cache)
[ffff8d45f78e0600]
ffff8d45f78e0800 (cpu 4 cache)
ffff8d45f78e0a00 (cpu 4 cache)
ffff8d45f78e0c00 (cpu 4 cache)
ffff8d45f78e0e00 (cpu 4 cache)
ffff8d45f78e1000 (cpu 4 cache)
ffff8d45f78e1200 (cpu 4 cache)
ffff8d45f78e1400 (cpu 4 cache)
[ffff8d45f78e1600]
...skipped ...
Signed-off-by: Aaron Tomlin <atomlin at redhat.com>
---
help.c | 5 ++++-
memory.c | 47 +++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 47 insertions(+), 5 deletions(-)
diff --git a/help.c b/help.c
index e0c8408..8d40204 100644
--- a/help.c
+++ b/help.c
@@ -6571,7 +6571,7 @@ char *help_kmem[] = {
"kmem",
"kernel memory",
"[-f|-F|-c|-C|-i|-v|-V|-n|-z|-o|-h] [-p | -m member[,member]]\n"
-" [[-s|-S|-r] [slab] [-I slab[,slab]]] [-g [flags]] [[-P] address]]",
+" [[-s|-S|-S=cpu[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.",
@@ -6616,6 +6616,9 @@ 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.",
+" Note: one can specify the per-cpu slab data to be displayed;",
+" the cpu[s] can be given as \"1,3,5\", \"1-3\", \"1,3,5-7,10\",",
+" \"all\", or \"a\" (shortcut for \"all\").",
" -r displays the accumulated basic kmalloc() slab data of each",
" root slab cache and its children. The kernel must contain the",
" \"slab_root_caches\" list_head. (currently only available if",
diff --git a/memory.c b/memory.c
index 8c6bbe4..ef7c3ec 100644
--- a/memory.c
+++ b/memory.c
@@ -47,6 +47,7 @@ struct meminfo { /* general purpose memory information structure */
int slab_offset;
char *reqname;
char *curname;
+ ulong *spec_cpumask;
ulong *addrlist;
int *kmem_bufctl;
ulong *cpudata[NR_CPUS];
@@ -4850,10 +4851,13 @@ cmd_kmem(void)
struct meminfo meminfo;
ulonglong value[MAXARGS];
char buf[BUFSIZE];
+ char arg_buf[BUFSIZE];
char *p1;
- int spec_addr, escape;
+ ulong *cpus;
+ int spec_addr, escape, choose_cpu;
- spec_addr = 0;
+ cpus = NULL;
+ spec_addr = choose_cpu = 0;
sflag = Sflag = pflag = fflag = Fflag = Pflag = zflag = oflag = 0;
vflag = Cflag = cflag = iflag = nflag = lflag = Lflag = Vflag = 0;
gflag = hflag = rflag = 0;
@@ -4862,7 +4866,7 @@ cmd_kmem(void)
BZERO(&value[0], sizeof(ulonglong)*MAXARGS);
pc->curcmd_flags &= ~HEADER_PRINTED;
- while ((c = getopt(argcnt, args, "gI:sSrFfm:pvczCinl:L:PVoh")) != EOF) {
+ while ((c = getopt(argcnt, args, "gI:sS::rFfm:pvczCinl:L:PVoh")) != EOF) {
switch(c)
{
case 'V':
@@ -4902,6 +4906,33 @@ cmd_kmem(void)
break;
case 'S':
+ if (choose_cpu)
+ error(FATAL, "only one -S option allowed\n");
+ /* Use the GNU extension with getopt(3) ... */
+ if (optarg) {
+ if (!(vt->flags & KMALLOC_SLUB))
+ error(FATAL,
+ "can only use -S=cpu(s) with a kernel \n"
+ "that is built with CONFIG_SLUB support.\n");
+ if (optarg[0] != '=')
+ error(FATAL,
+ "CPU-specific slab data to be displayed "
+ "must be written as expected only e.g. -S=1,45.\n");
+ /* Skip = ... */
+ optarg++;
+
+ choose_cpu = 1;
+ BZERO(arg_buf, BUFSIZE);
+ strcpy(arg_buf, optarg);
+
+ cpus = get_cpumask_buf();
+ make_cpumask(arg_buf, cpus, FAULT_ON_ERROR, NULL);
+ meminfo.spec_cpumask = cpus;
+
+ for (i = 0; i < kt->cpus; i++)
+ if (NUM_IN_BITMAP(cpus, i) && check_offline_cpu(i))
+ error(INFO, "CPU %d is OFFLINE.\n", i);
+ }
Sflag = 1; sflag = rflag = 0;
break;
@@ -5184,6 +5215,8 @@ cmd_kmem(void)
meminfo.flags = VERBOSE;
vt->dump_kmem_cache(&meminfo);
}
+ if (choose_cpu)
+ FREEBUF(cpus);
}
if (vflag == 1)
@@ -19079,7 +19112,13 @@ do_kmem_cache_slub(struct meminfo *si)
per_cpu = (ulong *)GETBUF(sizeof(ulong) * vt->numnodes);
for (i = 0; i < kt->cpus; i++) {
- if (hide_offline_cpu(i)) {
+ if (si->spec_cpumask) {
+ if (!(NUM_IN_BITMAP(si->spec_cpumask, i)))
+ continue;
+ else
+ if (check_offline_cpu(i))
+ continue;
+ } else if (hide_offline_cpu(i)) {
fprintf(fp, "CPU %d [OFFLINE]\n", i);
continue;
}
--
2.31.1
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