The patch defines kernel parameter "nptcg=". The parameter overrides max number
of concurrent global TLB purges which is reported from either PAL_VM_SUMMARY or
SAL PALO.
This patch is on the top of patch sent before:
http://www.gelato.unsw.edu.au/archives/linux-ia64/0801/21684.html
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
Documentation/kernel-parameters.txt | 4 +++
arch/ia64/kernel/efi.c | 2 -
arch/ia64/kernel/setup.c | 2 -
arch/ia64/mm/tlb.c | 46 ++++++++++++++++++++++++++++++++----
include/asm-ia64/sal.h | 4 +++
5 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 533e67f..3477a8b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1337,6 +1337,10 @@ and is between 256 and 4096 characters. It is defined in the file
nowb [ARM]
+ nptcg= [IA64] Override max number of concurrent global TLB
+ purges which is reported from either PAL_VM_SUMMARY or
+ SAL PALO.
+
numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
one of ['zone', 'node', 'default'] can be specified
This can be set from sysctl after boot.
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 003cd09..d45f215 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -436,7 +436,7 @@ static void __init handle_palo(unsigned long palo_phys)
return;
}
- setup_ptcg_sem(palo->max_tlb_purges, 1);
+ setup_ptcg_sem(palo->max_tlb_purges, NPTCG_FROM_PALO);
}
void
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 1cbd263..f798c07 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -949,7 +949,7 @@ cpu_init (void)
/* set ia64_ctx.max_rid to the maximum RID that is supported by all CPUs: */
if (ia64_pal_vm_summary(NULL, &vmi) == 0) {
max_ctx = (1U << (vmi.pal_vm_info_2_s.rid_size - 3)) - 1;
- setup_ptcg_sem(vmi.pal_vm_info_2_s.max_purges, 0);
+ setup_ptcg_sem(vmi.pal_vm_info_2_s.max_purges, NPTCG_FROM_PAL);
} else {
printk(KERN_WARNING "cpu_init: PAL VM summary failed, assuming 18 RID bits\n");
max_ctx = (1U << 15) - 1; /* use architected minimum */
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index 78767e5..2bafe7f 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -94,19 +94,45 @@ static int need_ptcg_sem = 1;
static int toolatetochangeptcgsem = 0;
/*
+ * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
+ * purges which is reported from either PAL or SAL PALO.
+ *
+ * We don't have sanity checking for nptcg value. It's the user's responsibility
+ * for valid nptcg value on the platform. Otherwise, kernel may hang in some
+ * cases.
+ */
+static int __init
+set_nptcg(char *str)
+{
+ int value = 0;
+
+ get_option(&str, &value);
+ setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER);
+
+ return 1;
+}
+
+__setup("nptcg=", set_nptcg);
+
+/*
* Maximum number of simultaneous ptc.g purges in the system can
* be defined by PAL_VM_SUMMARY (in which case we should take
* the smallest value for any cpu in the system) or by the PAL
* override table (in which case we should ignore the value from
* PAL_VM_SUMMARY).
*
+ * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g
+ * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case,
+ * we should ignore the value from either PAL_VM_SUMMARY or PAL override table.
+ *
* Complicating the logic here is the fact that num_possible_cpus()
* isn't fully setup until we start bringing cpus online.
*/
void
-setup_ptcg_sem(int max_purges, int from_palo)
+setup_ptcg_sem(int max_purges, int nptcg_from)
{
- static int have_palo;
+ static int kp_override;
+ static int palo_override;
static int firstcpu = 1;
if (toolatetochangeptcgsem) {
@@ -114,8 +140,18 @@ setup_ptcg_sem(int max_purges, int from_palo)
return;
}
- if (from_palo) {
- have_palo = 1;
+ if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
+ kp_override = 1;
+ nptcg = max_purges;
+ goto resetsema;
+ }
+ if (kp_override) {
+ need_ptcg_sem = num_possible_cpus() > nptcg;
+ return;
+ }
+
+ if (nptcg_from == NPTCG_FROM_PALO) {
+ palo_override = 1;
/* In PALO max_purges == 0 really means it! */
if (max_purges == 0)
@@ -127,7 +163,7 @@ setup_ptcg_sem(int max_purges, int from_palo)
}
goto resetsema;
}
- if (have_palo) {
+ if (palo_override) {
if (nptcg != PALO_MAX_TLB_PURGES)
need_ptcg_sem = (num_possible_cpus() > nptcg);
return;
diff --git a/include/asm-ia64/sal.h b/include/asm-ia64/sal.h
index 3cd637a..89594b4 100644
--- a/include/asm-ia64/sal.h
+++ b/include/asm-ia64/sal.h
@@ -896,6 +896,10 @@ struct palo_table {
u8 reserved2[6];
};
+#define NPTCG_FROM_PAL 0
+#define NPTCG_FROM_PALO 1
+#define NPTCG_FROM_KERNEL_PARAMETER 2
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_IA64_SAL_H */
--
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