Re: [PATCH -tip] cpuacct: per-cgroup utime/stime statistics - v4

From: Andrew Morton
Date: Mon Mar 23 2009 - 07:33:18 EST


On Mon, 23 Mar 2009 10:05:38 +0530 Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx> wrote:

> +static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
> + struct cgroup_map_cb *cb)
> +{
> + struct cpuacct *ca = cgroup_ca(cgrp);
> + int i;
> +
> + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
> + s64 val = percpu_counter_read(&ca->cpustat[i]);
> + val = cputime_to_clock_t(val);
> + cb->fill(cb, cpuacct_stat_desc[i], val);
> + }
> + return 0;
> +}

I'd have expected `val' to have type clock_t. But clock_t is 32-bit on
32-bit x86.

Is it correct to pass a 64-bit value to a function which takes a 32-bit
value and to then copy the 32-bit return value into a 64-bit variable?


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