On Fri, Apr 25, 2008 at 03:33:52PM -0500, Cliff Wickman wrote:
>
> In Neil's patch:
> > + int ncpumask = (1<<(sysconf(_SC_NPROCESSORS_CONF)))-1;
> > /*
> > * The maximum line size consists of the string at the beginning plus
> > * a digit for each 4 cpus and a comma for each 64 cpus.
> > @@ -480,10 +481,22 @@ set_thread_constraints(void)
> > fclose(f);
> > free (buffer);
> >
> > - if (maxprocnode < 0) {
> > + /*
> > + * Cps_allowed in the kenrel can be defined to all f's
> > + * i.e. it may be a superset of the actual available processors
> > + * as such lets reduce maxproccpu with a mask of the actual
> > + * available cpus
> > + */
> > + maxproccpu &= ncpumask;
>
> I agree with the fix as long as the number of cpus does not exceed
> the number of bits in an int. But that's a pretty small constraint.
> I propose to trim maxprocnode to the number of configured cpus - 1.
> (And fix the numa_all_cpus_ptr map of all cpus as well)
>
>
> Then, in testing, I found that read_mask() was buggy. (the regression
> tests don't uncover that). So that needed some tweaks as well.
>
> Can you give that a try?
>
Yep, seems to work just fine for me.
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
> Signed-off-by: Cliff Wickman <cpw@xxxxxxx>
>
> ---
> libnuma.c | 30 ++++++++++++++++++++++++++++--
> 1 file changed, 28 insertions(+), 2 deletions(-)
>
> Index: numactl-dev/libnuma.c
> ===================================================================
> --- numactl-dev.orig/libnuma.c
> +++ numactl-dev/libnuma.c
> @@ -394,6 +394,7 @@ int
> read_mask(char *s, struct bitmask *bmp)
> {
> char *end = s;
> + char *prevend;
> unsigned int *start = (unsigned int *)bmp->maskp;
> unsigned int *p = start;
> unsigned int *q;
> @@ -402,9 +403,13 @@ read_mask(char *s, struct bitmask *bmp)
>
> i = strtoul(s, &end, 16);
>
> + prevend = end;
> /* Skip leading zeros */
> - while (!i && *end++ == ',')
> + while (!i && *end++ == ',') {
> + prevend = end;
> i = strtoul(end, &end, 16);
> + }
> + end = prevend;
>
> if (!i)
> /* End of string. No mask */
> @@ -436,7 +441,7 @@ read_mask(char *s, struct bitmask *bmp)
> /*
> * Return the last bit set
> */
> - return sizeof(unsigned int) * n + i;
> + return ((sizeof(unsigned int)*8) * n) + i;
> }
>
> /*
> @@ -447,7 +452,9 @@ void
> set_thread_constraints(void)
> {
> int max_cpus = numa_num_possible_cpus();
> + int hicpu = sysconf(_SC_NPROCESSORS_CONF)-1;
> int buflen;
> + int i;
> char *buffer;
> FILE *f;
> /*
> @@ -480,6 +487,25 @@ set_thread_constraints(void)
> fclose(f);
> free (buffer);
>
> + /*
> + * Cpus_allowed in the kernel can be defined to all f's
> + * i.e. it may be a superset of the actual available processors.
> + * As such let's reduce maxproccpu to the number of actual
> + * available cpus - 1.
> + */
> + if (maxproccpu > hicpu) {
> + maxproccpu = hicpu;
> + for (i=hicpu+1; i<numa_all_cpus_ptr->size; i++) {
> + numa_bitmask_clearbit(numa_all_cpus_ptr, i);
> + }
> + }
> +
> + /*
> + * Sanity checks
> + */
> + if (maxproccpu == 0)
> + numa_warn(W_cpumap, "Available cpus are empty set");
> +
> if (maxprocnode < 0) {
> numa_warn(W_cpumap, "Cannot parse %s", mask_size_file);
> return;
--
/****************************************************
* Neil Horman <nhorman@xxxxxxxxxxxxx>
* Software Engineer, Red Hat
****************************************************/
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