diff mbox series

[v2,3/4] KVM: Allow custom names for KVM_STAT()

Message ID 20230306190156.434452-4-dmatlack@google.com (mailing list archive)
State Handled Elsewhere
Headers show
Series KVM: Refactor KVM stats macros and enable custom stat names | expand

Checks

Context Check Description
conchuod/cover_letter success Series has a cover letter
conchuod/tree_selection success Guessed tree name to be for-next
conchuod/fixes_present success Fixes tag not required for -next series
conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 1 and now 1
conchuod/verify_signedoff success Signed-off-by tag matches author and committer
conchuod/kdoc success Errors and warnings before: 0 this patch: 0
conchuod/build_rv64_clang_allmodconfig success Errors and warnings before: 18 this patch: 18
conchuod/module_param success Was 0 now: 0
conchuod/build_rv64_gcc_allmodconfig success Errors and warnings before: 34 this patch: 34
conchuod/alphanumeric_selects success Out of order selects before the patch: 728 and now 728
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 3 this patch: 3
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch success total: 0 errors, 0 warnings, 0 checks, 59 lines checked
conchuod/source_inline success Was 0 now: 0
conchuod/build_rv64_nommu_k210_defconfig success Build OK
conchuod/verify_fixes success No Fixes tag
conchuod/build_rv64_nommu_virt_defconfig success Build OK

Commit Message

David Matlack March 6, 2023, 7:01 p.m. UTC 
Allow custom names to be specified for stats built on KVM_STAT() via a
new inner macro __KVM_STAT(). e.g.

  KVM_STAT(VM, CUMULATIVE, NONE, foo),
  __KVM_STAT(VM, CUMULATIVE, NONE, bar, "custom_name"),
  ...

Custom name support enables decoupling the userspace-visible stat names
from their internal representation in C. This can allow future commits
to refactor the various stats structs without impacting userspace tools
that read KVM stats.

This also allows stats to be stored in data structures such as arrays,
without needing unions to access specific stats. For example, the union
for pages_{4k,2m,1g} is no longer necessary. At Google, we have several
other out-of-tree stats that would benefit from this support.

No functional change intended.

Link: https://lore.kernel.org/all/20211019000459.3163029-1-jingzhangos@google.com/
Suggested-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
---
 include/linux/kvm_host.h | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6673ae757c4e..fa026e8997b2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1761,40 +1761,43 @@  struct _kvm_stats_desc {
 	.name = _name,							       \
 }
 
-#define VM_GENERIC_STATS_DESC(_stat, _type, _unit, _base, _exponent, _size,    \
-			      _bucket_size)				       \
-	_KVM_STATS_DESC(struct kvm_vm_stat, generic._stat, #_stat, _type,      \
+#define VM_GENERIC_STATS_DESC(_stat, _name, _type, _unit, _base, _exponent,    \
+			      _size, _bucket_size)			       \
+	_KVM_STATS_DESC(struct kvm_vm_stat, generic._stat, _name, _type,       \
 			_unit, _base, _exponent, _size, _bucket_size)
 
-#define VCPU_GENERIC_STATS_DESC(_stat, _type, _unit, _base, _exponent, _size,  \
-				_bucket_size)				       \
-	_KVM_STATS_DESC(struct kvm_vcpu_stat, generic._stat, #_stat, _type,    \
+#define VCPU_GENERIC_STATS_DESC(_stat, _name, _type, _unit, _base, _exponent,  \
+				_size, _bucket_size)			       \
+	_KVM_STATS_DESC(struct kvm_vcpu_stat, generic._stat, _name, _type,     \
 			_unit, _base, _exponent, _size, _bucket_size)
 
-#define VM_STATS_DESC(_stat, _type, _unit, _base, _exponent, _size,	       \
+#define VM_STATS_DESC(_stat, _name, _type, _unit, _base, _exponent, _size,     \
 		      _bucket_size)					       \
-	_KVM_STATS_DESC(struct kvm_vm_stat, _stat, #_stat, _type, _unit,       \
+	_KVM_STATS_DESC(struct kvm_vm_stat, _stat, _name, _type, _unit,	       \
 			_base, _exponent, _size, _bucket_size)
 
-#define VCPU_STATS_DESC(_stat, _type, _unit, _base, _exponent, _size,	       \
+#define VCPU_STATS_DESC(_stat, _name, _type, _unit, _base, _exponent, _size,   \
 			_bucket_size)					       \
-	_KVM_STATS_DESC(struct kvm_vcpu_stat, _stat, #_stat, _type, _unit,     \
+	_KVM_STATS_DESC(struct kvm_vcpu_stat, _stat, _name, _type, _unit,      \
 			_base, _exponent, _size, _bucket_size)
 
 /* SCOPE: VM, VM_GENERIC, VCPU, VCPU_GENERIC */
-#define STATS_DESC(SCOPE, stat, type, unit, base, exp, sz, bsz)		       \
-	SCOPE##_STATS_DESC(stat, type, unit, base, exp, sz, bsz)
+#define STATS_DESC(SCOPE, stat, name, type, unit, base, exp, sz, bsz)	       \
+	SCOPE##_STATS_DESC(stat, name, type, unit, base, exp, sz, bsz)
 
-#define KVM_STAT(SCOPE, TYPE, UNIT, _stat)				       \
-	STATS_DESC(SCOPE, _stat, KVM_STATS_TYPE_##TYPE,			       \
+#define __KVM_STAT(SCOPE, TYPE, UNIT, _stat, _name)			       \
+	STATS_DESC(SCOPE, _stat, _name, KVM_STATS_TYPE_##TYPE,		       \
 		   KVM_STATS_UNIT_##UNIT, KVM_STATS_BASE_POW10, 0, 1, 0)
 
+#define KVM_STAT(SCOPE, TYPE, UNIT, _stat)				       \
+	__KVM_STAT(SCOPE, TYPE, UNIT, _stat, #_stat)
+
 #define KVM_STAT_NSEC(SCOPE, _stat)					       \
-	STATS_DESC(SCOPE, _stat, KVM_STATS_TYPE_CUMULATIVE,		       \
+	STATS_DESC(SCOPE, _stat, #_stat, KVM_STATS_TYPE_CUMULATIVE,	       \
 		   KVM_STATS_UNIT_SECONDS, KVM_STATS_BASE_POW10, -9, 1, 0)
 
 #define KVM_HIST_NSEC(SCOPE, TYPE, _stat, _size, _bucket_size)		       \
-	STATS_DESC(VCPU_GENERIC, _stat, KVM_STATS_TYPE_##TYPE##_HIST,	       \
+	STATS_DESC(VCPU_GENERIC, _stat, #_stat, KVM_STATS_TYPE_##TYPE##_HIST,  \
 		   KVM_STATS_UNIT_SECONDS, KVM_STATS_BASE_POW10, -9,	       \
 		   _size, _bucket_size)