Re: SLUB: statistics improvements

From: Eric Dumazet
Date: Wed Feb 06 2008 - 16:41:20 EST


Christoph Lameter a écrit :
SLUB: statistics improvements

- Fix indentation in unfreeze_slab

- FREE_SLAB/ALLOC_SLAB counters were slightly misplaced and counted
even if the slab was kept because we were below the mininum of
partial slabs.

- Export per cpu statistics to user space (follow numa convention
but change the n character to c (no slabinfo support for display yet)

F.e.

christoph@stapp:/sys/kernel/slab/kmalloc-8$ cat alloc_fastpath
9968 c0=4854 c1=1050 c2=468 c3=190 c4=116 c5=1779 c6=185 c7=1326

nice :)



+static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
+{
+ unsigned long sum = 0;
+ int cpu;
+ int len;
+ int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
+
+ if (!data)
+ return -ENOMEM;
+
+ for_each_online_cpu(cpu) {
+ int x = get_cpu_slab(s, cpu)->stat[si];

unsigned int x = ...

+
+ data[cpu] = x;
+ sum += x;

or else x will sign extend here on 64 bit arches ?

+ }
+
+ len = sprintf(buf, "%lu", sum);
+
+ for_each_online_cpu(cpu) {
+ if (data[cpu] && len < PAGE_SIZE - 20)
+ len += sprintf(buf + len, " c%d=%u", cpu, data[cpu]);
+ }
+ kfree(data);
+ return len + sprintf(buf + len, "\n");
+}
+


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