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powerpc: Fix regression introduced in r342771

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In r342771, I introduced a regression in Power by abusing the platform
smp_topo() method as a shortcut for providing the MI information needed for
the stated sysctls.  The smp_topo() method was already called later by
sched_ule (under the name cpu_topo()), and initializes a static array of
scheduler topology information.  I had skimmed the smp_topo_foo() functions
and assumed they were idempotent; empirically, they are not (or at least,
detect re-initialization and panic).

Do the cleaner thing I should have done in the first place and add a
platform method specifically for core- and thread-count probing.

Reported by:	luporl via jhibbits
Reviewed by:	luporl
X-MFC-With:	r342771
Differential Revision:	https://reviews.freebsd.org/D18777
This commit is contained in:
Conrad Meyer 2019-01-07 19:39:31 +00:00
parent bdd8abc6d6
commit bba9cbe374
7 changed files with 61 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/powerpc/include/platform.h
View File

@ -58,6 +58,7 @@ int platform_smp_get_bsp(struct cpuref *);
int platform_smp_start_cpu(struct pcpu *);
void platform_smp_timebase_sync(u_long tb, int ap);
void platform_smp_ap_init(void);
void platform_smp_probe_threads(void);
const char *installed_platform(void);
void platform_probe_and_attach(void);

23
sys/powerpc/powernv/platform_powernv.c
View File

@ -71,6 +71,7 @@ static int powernv_smp_get_bsp(platform_t, struct cpuref *cpuref);
static void powernv_smp_ap_init(platform_t);
#ifdef SMP
static int powernv_smp_start_cpu(platform_t, struct pcpu *cpu);
static void powernv_smp_probe_threads(platform_t);
static struct cpu_group *powernv_smp_topo(platform_t plat);
#endif
static void powernv_reset(platform_t);
@ -89,6 +90,7 @@ static platform_method_t powernv_methods[] = {
PLATFORMMETHOD(platform_smp_get_bsp, powernv_smp_get_bsp),
#ifdef SMP
PLATFORMMETHOD(platform_smp_start_cpu, powernv_smp_start_cpu),
PLATFORMMETHOD(platform_smp_probe_threads, powernv_smp_probe_threads),
PLATFORMMETHOD(platform_smp_topo, powernv_smp_topo),
#endif
@ -403,8 +405,8 @@ powernv_smp_start_cpu(platform_t plat, struct pcpu *pc)
return (0);
}
static struct cpu_group *
powernv_smp_topo(platform_t plat)
static void
powernv_smp_probe_threads(platform_t plat)
{
char buf[8];
phandle_t cpu, dev, root;
@ -436,21 +438,26 @@ powernv_smp_topo(platform_t plat)
}
smp_threads_per_core = nthreads;
if (mp_ncpus % nthreads == 0)
mp_ncores = mp_ncpus / nthreads;
}
if (mp_ncpus % nthreads != 0) {
static struct cpu_group *
powernv_smp_topo(platform_t plat)
{
if (mp_ncpus % smp_threads_per_core != 0) {
printf("WARNING: Irregular SMP topology. Performance may be "
"suboptimal (%d threads, %d on first core)\n",
mp_ncpus, nthreads);
mp_ncpus, smp_threads_per_core);
return (smp_topo_none());
}
mp_ncores = mp_ncpus / nthreads;
/* Don't do anything fancier for non-threaded SMP */
if (nthreads == 1)
if (smp_threads_per_core == 1)
return (smp_topo_none());
return (smp_topo_1level(CG_SHARE_L1, nthreads, CG_FLAG_SMT));
return (smp_topo_1level(CG_SHARE_L1, smp_threads_per_core,
CG_FLAG_SMT));
}
#endif

3
sys/powerpc/powerpc/mp_machdep.c
View File

@ -188,8 +188,7 @@ cpu_mp_start(void)
}
#ifdef SMP
/* Probe mp_ncores and smp_threads_per_core as a side effect. */
(void)cpu_topo();
platform_smp_probe_threads();
#endif
}

6
sys/powerpc/powerpc/platform.c
View File

@ -242,6 +242,12 @@ platform_smp_ap_init()
PLATFORM_SMP_AP_INIT(plat_obj);
}
void
platform_smp_probe_threads(void)
{
PLATFORM_SMP_PROBE_THREADS(plat_obj);
}
#ifdef SMP
struct cpu_group *
cpu_topo(void)

11
sys/powerpc/powerpc/platform_if.m
View File

@ -84,6 +84,10 @@ CODE {
{
return;
}
static void platform_null_smp_probe_threads(void)
{
return;
}
};
/**
@ -196,6 +200,13 @@ METHOD void smp_ap_init {
platform_t _plat;
} DEFAULT platform_null_smp_ap_init;
/**
* @brief Probe mp_ncores and smp_threads_per_core for early MI code
*/
METHOD void smp_probe_threads {
platform_t _plat;
} DEFAULT platform_null_smp_probe_threads;
/**
* @brief Return SMP topology
*/

11
sys/powerpc/ps3/platform_ps3.c
View File

@ -70,6 +70,7 @@ static int ps3_smp_first_cpu(platform_t, struct cpuref *cpuref);
static int ps3_smp_next_cpu(platform_t, struct cpuref *cpuref);
static int ps3_smp_get_bsp(platform_t, struct cpuref *cpuref);
static int ps3_smp_start_cpu(platform_t, struct pcpu *cpu);
static void ps3_smp_probe_threads(platform_t);
static struct cpu_group *ps3_smp_topo(platform_t);
#endif
static void ps3_reset(platform_t);
@ -87,6 +88,7 @@ static platform_method_t ps3_methods[] = {
PLATFORMMETHOD(platform_smp_next_cpu, ps3_smp_next_cpu),
PLATFORMMETHOD(platform_smp_get_bsp, ps3_smp_get_bsp),
PLATFORMMETHOD(platform_smp_start_cpu, ps3_smp_start_cpu),
PLATFORMMETHOD(platform_smp_probe_threads, ps3_smp_probe_threads),
PLATFORMMETHOD(platform_smp_topo, ps3_smp_topo),
#endif
@ -243,11 +245,16 @@ ps3_smp_start_cpu(platform_t plat, struct pcpu *pc)
return ((pc->pc_awake) ? 0 : EBUSY);
}
static struct cpu_group *
ps3_smp_topo(platform_t plat)
static void
ps3_smp_probe_threads(platform_t plat)
{
mp_ncores = 1;
smp_threads_per_core = 2;
}
static struct cpu_group *
ps3_smp_topo(platform_t plat)
{
return (smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_SMT));
}
#endif

28
sys/powerpc/pseries/platform_chrp.c
View File

@ -78,6 +78,7 @@ static void chrp_smp_ap_init(platform_t);
static int chrp_cpuref_init(void);
#ifdef SMP
static int chrp_smp_start_cpu(platform_t, struct pcpu *cpu);
static void chrp_smp_probe_threads(platform_t plat);
static struct cpu_group *chrp_smp_topo(platform_t plat);
#endif
static void chrp_reset(platform_t);
@ -103,6 +104,7 @@ static platform_method_t chrp_methods[] = {
PLATFORMMETHOD(platform_smp_get_bsp, chrp_smp_get_bsp),
#ifdef SMP
PLATFORMMETHOD(platform_smp_start_cpu, chrp_smp_start_cpu),
PLATFORMMETHOD(platform_smp_probe_threads, chrp_smp_probe_threads),
PLATFORMMETHOD(platform_smp_topo, chrp_smp_topo),
#endif
@ -499,13 +501,13 @@ chrp_smp_start_cpu(platform_t plat, struct pcpu *pc)
return ((pc->pc_awake) ? 0 : EBUSY);
}
static struct cpu_group *
chrp_smp_topo(platform_t plat)
static void
chrp_smp_probe_threads(platform_t plat)
{
struct pcpu *pc, *last_pc;
int i, ncores, ncpus;
int i, ncores;
ncores = ncpus = 0;
ncores = 0;
last_pc = NULL;
for (i = 0; i <= mp_maxid; i++) {
pc = pcpu_find(i);
@ -514,23 +516,29 @@ chrp_smp_topo(platform_t plat)
if (last_pc == NULL || pc->pc_hwref != last_pc->pc_hwref)
ncores++;
last_pc = pc;
ncpus++;
}
mp_ncores = ncores;
if (mp_ncpus % ncores == 0)
smp_threads_per_core = mp_ncpus / ncores;
}
if (ncpus % ncores != 0) {
static struct cpu_group *
chrp_smp_topo(platform_t plat)
{
if (mp_ncpus % mp_ncores != 0) {
printf("WARNING: Irregular SMP topology. Performance may be "
"suboptimal (%d CPUS, %d cores)\n", ncpus, ncores);
"suboptimal (%d CPUS, %d cores)\n", mp_ncpus, mp_ncores);
return (smp_topo_none());
}
/* Don't do anything fancier for non-threaded SMP */
if (ncpus == ncores)
if (mp_ncpus == mp_ncores)
return (smp_topo_none());
smp_threads_per_core = ncpus / ncores;
return (smp_topo_1level(CG_SHARE_L1, ncpus / ncores, CG_FLAG_SMT));
return (smp_topo_1level(CG_SHARE_L1, smp_threads_per_core,
CG_FLAG_SMT));
}
#endif