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x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box()

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When a vSMP Foundation box is detected, the function apic_cluster_num() counts
the number of APIC clusters found. If more than one found, a multi board
configuration is assumed, and TSC marked as unstable. This behavior is
incorrect as vSMP Foundation may use processors from single node only, attached
to memory of other nodes - and such node may have more than one APIC cluster
(typically any recent intel box has more than single APIC_CLUSTERID(x)).

To fix this, we simply remove the code which detects a vSMP Foundation box and
affects apic_is_clusted_box() return value. This can be done because later the
kernel checks by itself if the TSC is stable using the
check_tsc_sync_[source|target]() functions and marks TSC as unstable if needed.

Acked-by: Shai Fultheim <shai@scalemp.com>
Signed-off-by: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@scalemp.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Oren Twaig 2014-06-29 13:01:08 +03:00 committed by H. Peter Anvin
parent b81975eade
commit 411cf9ee29
2 changed files with 1 additions and 67 deletions
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8
arch/x86/include/asm/apic.h
View file

@ -85,14 +85,6 @@ static inline bool apic_from_smp_config(void)
#include <asm/paravirt.h>
#endif
#ifdef CONFIG_X86_64
extern int is_vsmp_box(void);
#else
static inline int is_vsmp_box(void)
{
return 0;
}
#endif
extern int setup_profiling_timer(unsigned int);
static inline void native_apic_mem_write(u32 reg, u32 v)

60
arch/x86/kernel/apic/apic.c
View file

@ -2451,51 +2451,6 @@ static void apic_pm_activate(void) { }
#ifdef CONFIG_X86_64
static int apic_cluster_num(void)
{
int i, clusters, zeros;
unsigned id;
u16 *bios_cpu_apicid;
DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid);
bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
for (i = 0; i < nr_cpu_ids; i++) {
/* are we being called early in kernel startup? */
if (bios_cpu_apicid) {
id = bios_cpu_apicid[i];
} else if (i < nr_cpu_ids) {
if (cpu_present(i))
id = per_cpu(x86_bios_cpu_apicid, i);
else
continue;
} else
break;
if (id != BAD_APICID)
__set_bit(APIC_CLUSTERID(id), clustermap);
}
/* Problem: Partially populated chassis may not have CPUs in some of
* the APIC clusters they have been allocated. Only present CPUs have
* x86_bios_cpu_apicid entries, thus causing zeroes in the bitmap.
* Since clusters are allocated sequentially, count zeros only if
* they are bounded by ones.
*/
clusters = 0;
zeros = 0;
for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
if (test_bit(i, clustermap)) {
clusters += 1 + zeros;
zeros = 0;
} else
++zeros;
}
return clusters;
}
static int multi_checked;
static int multi;
@ -2540,20 +2495,7 @@ static void dmi_check_multi(void)
int apic_is_clustered_box(void)
{
dmi_check_multi();
if (multi)
return 1;
if (!is_vsmp_box())
return 0;
/*
* ScaleMP vSMPowered boxes have one cluster per board and TSCs are
* not guaranteed to be synced between boards
*/
if (apic_cluster_num() > 1)
return 1;
return 0;
return multi;
}
#endif