[PATCH v3] x86/oprofile: switch to xv[mz]alloc_array()

[PATCH v3] x86/oprofile: switch to xv[mz]alloc_array()

[Jan Beulich]

Use the more "modern" forms, thus doing away with effectively open-
coding xmalloc_array() at the same time. While there is a difference in
generated code, as xmalloc_bytes() forces SMP_CACHE_BYTES alignment, if
code really cared about such higher than default alignment, it should
request so explicitly.

While at it also use XVFREE() instead of open-coding it, or instead of
leaving a dangling pointer, and change loop induction variable types.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v3: Use xvmalloc*(), extending to op_model_ppro.c as well.

--- a/xen/arch/x86/oprofile/nmi_int.c
+++ b/xen/arch/x86/oprofile/nmi_int.c
@@ -19,7 +19,10 @@
 #include <xen/string.h>
 #include <xen/delay.h>
 #include <xen/xenoprof.h>
+#include <xen/xvmalloc.h>
+
 #include <public/xenoprof.h>
+
 #include <asm/msr.h>
 #include <asm/apic.h>
 #include <asm/regs.h>
@@ -142,30 +145,29 @@ static void cf_check nmi_save_registers(
 
 static void free_msrs(void)
 {
-	int i;
+	unsigned int i;
+
 	for (i = 0; i < nr_cpu_ids; ++i) {
-		xfree(cpu_msrs[i].counters);
-		cpu_msrs[i].counters = NULL;
-		xfree(cpu_msrs[i].controls);
-		cpu_msrs[i].controls = NULL;
+		XVFREE(cpu_msrs[i].counters);
+		XVFREE(cpu_msrs[i].controls);
 	}
 }
 
 
 static int allocate_msrs(void)
 {
+	unsigned int i;
 	int success = 1;
-	size_t controls_size = sizeof(struct op_msr) * model->num_controls;
-	size_t counters_size = sizeof(struct op_msr) * model->num_counters;
 
-	int i;
 	for_each_online_cpu (i) {
-		cpu_msrs[i].counters = xmalloc_bytes(counters_size);
+		cpu_msrs[i].counters = xvmalloc_array(struct op_msr,
+						      model->num_counters);
 		if (!cpu_msrs[i].counters) {
 			success = 0;
 			break;
 		}
-		cpu_msrs[i].controls = xmalloc_bytes(controls_size);
+		cpu_msrs[i].controls = xvmalloc_array(struct op_msr,
+						      model->num_controls);
 		if (!cpu_msrs[i].controls) {
 			success = 0;
 			break;
--- a/xen/arch/x86/oprofile/op_model_ppro.c
+++ b/xen/arch/x86/oprofile/op_model_ppro.c
@@ -10,9 +10,11 @@
  * @author Graydon Hoare
  */
 
+#include <xen/sched.h>
 #include <xen/types.h>
 #include <xen/xenoprof.h>
-#include <xen/sched.h>
+#include <xen/xvmalloc.h>
+
 #include <asm/msr.h>
 #include <asm/io.h>
 #include <asm/apic.h>
@@ -231,7 +233,7 @@ static int cf_check ppro_allocate_msr(st
 	struct vpmu_struct *vpmu = vcpu_vpmu(v);
 	struct arch_msr_pair *msr_content;
 
-	msr_content = xzalloc_array(struct arch_msr_pair, num_counters);
+	msr_content = xvzalloc_array(struct arch_msr_pair, num_counters);
 	if ( !msr_content )
 		goto out;
 	vpmu->context = (void *)msr_content;
@@ -251,7 +253,7 @@ static void cf_check ppro_free_msr(struc
 
 	if ( !vpmu_is_set(vpmu, VPMU_PASSIVE_DOMAIN_ALLOCATED) )
 		return;
-	xfree(vpmu->context);
+	XVFREE(vpmu->context);
 	vpmu_reset(vpmu, VPMU_PASSIVE_DOMAIN_ALLOCATED);
 }
 

Re: [PATCH v3] x86/oprofile: switch to xv[mz]alloc_array()

[Roger Pau Monné]

On Mon, Jul 28, 2025 at 01:27:48PM +0200, Jan Beulich wrote:
> Use the more "modern" forms, thus doing away with effectively open-
> coding xmalloc_array() at the same time. While there is a difference in
> generated code, as xmalloc_bytes() forces SMP_CACHE_BYTES alignment, if
> code really cared about such higher than default alignment, it should
> request so explicitly.
> 
> While at it also use XVFREE() instead of open-coding it, or instead of
> leaving a dangling pointer, and change loop induction variable types.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Roger Pau Monné <roger.pau@cloud.com>

Thanks, Roger.