| Message ID | 20210602094347.3730846-8-qperret@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Reduce hyp_vmemmap overhead | expand |
diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h index 3fe34fa30ea4..592b7edb3edb 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/memory.h +++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h @@ -8,7 +8,7 @@ #include <linux/types.h> struct hyp_page { - unsigned int refcount; + unsigned short refcount; unsigned short order; }; diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c index be07055bbc10..41fc25bdfb34 100644 --- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c +++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c @@ -146,6 +146,7 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool, static inline void hyp_page_ref_inc(struct hyp_page *p) { + BUG_ON(p->refcount == USHRT_MAX); p->refcount++; }
The hyp_page refcount is currently encoded on 4 bytes even though we never need to count that many objects in a page. Make it 2 bytes to save some space in the vmemmap. As overflows are more likely to happen as well, make sure to catch those with a BUG in the increment function. Signed-off-by: Quentin Perret <qperret@google.com> --- arch/arm64/kvm/hyp/include/nvhe/memory.h | 2 +- arch/arm64/kvm/hyp/nvhe/page_alloc.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-)