linux-kernel - [PATCH v2 2/2] KVM: Shrink struct kvm_mmu_memory

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Message-Id: <20230217193336.15278-3-minipli@grsecurity.net>
Date:   Fri, 17 Feb 2023 20:33:36 +0100
From:   Mathias Krause <minipli@...ecurity.net>
To:     kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Mathias Krause <minipli@...ecurity.net>
Subject: [PATCH v2 2/2] KVM: Shrink struct kvm_mmu_memory_cache

Move the 'capacity' member around to make use of the padding hole on 64
bit systems instead of introducing yet another one.

This allows us to save 8 bytes per instance for 64 bit builds of which,
e.g., x86's struct kvm_vcpu_arch has a few.

Signed-off-by: Mathias Krause <minipli@...ecurity.net>
---
v2: use order as suggested by Sean

 include/linux/kvm_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index 76de36e56cdf..0b2ddce47f11 100644
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -91,11 +91,11 @@ struct gfn_to_pfn_cache {
  * is topped up (__kvm_mmu_topup_memory_cache()).
  */
 struct kvm_mmu_memory_cache {
-	int nobjs;
 	gfp_t gfp_zero;
 	gfp_t gfp_custom;
 	struct kmem_cache *kmem_cache;
 	int capacity;
+	int nobjs;
 	void **objects;
 };
 #endif
-- 
2.39.1