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Use SFINAE for varying API on pagemap

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This commit is contained in:
Matthew Parkinson
2021-07-16 09:51:29 +01:00
committed by Matthew Parkinson
parent 8b1ffbc166
commit 686cb3321f
1 changed files with 34 additions and 39 deletions
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73
src/backend/pagemap.h
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@@ -51,52 +51,47 @@ namespace snmalloc
public: public:
constexpr FlatPagemap() = default; constexpr FlatPagemap() = default;
template<typename ASM> template<typename ASM, bool has_bounds_ = has_bounds>
void init(ASM* a, address_t b = 0, size_t s = 0) std::enable_if_t<has_bounds_> init(ASM* a, address_t b, size_t s)
{ {
if constexpr (has_bounds) static_assert(
{ has_bounds_ == has_bounds, "Don't set SFINAE template parameter!");
#ifdef SNMALLOC_TRACING #ifdef SNMALLOC_TRACING
std::cout << "Pagemap.init " << (void*)b << " (" << s << ")" std::cout << "Pagemap.init " << (void*)b << " (" << s << ")" << std::endl;
<< std::endl;
#endif #endif
SNMALLOC_ASSERT(s != 0); SNMALLOC_ASSERT(s != 0);
// Align the start and end. We won't store for the very ends as they // Align the start and end. We won't store for the very ends as they
// are not aligned to a chunk boundary. // are not aligned to a chunk boundary.
base = bits::align_up(b, bits::one_at_bit(GRANULARITY_BITS)); base = bits::align_up(b, bits::one_at_bit(GRANULARITY_BITS));
auto end = bits::align_down(b + s, bits::one_at_bit(GRANULARITY_BITS)); auto end = bits::align_down(b + s, bits::one_at_bit(GRANULARITY_BITS));
size = end - base; size = end - base;
body = a->template reserve<false, false>( body = a->template reserve<false, false>(
bits::next_pow2((size >> SHIFT) * sizeof(T))) bits::next_pow2((size >> SHIFT) * sizeof(T)))
.template as_static<T>() .template as_static<T>()
.unsafe_ptr(); .unsafe_ptr();
; }
}
else
{
// The parameters should not be set without has_bounds.
UNUSED(s);
UNUSED(b);
SNMALLOC_ASSERT(s == 0);
SNMALLOC_ASSERT(b == 0);
static constexpr size_t COVERED_BITS = template<typename ASM, bool has_bounds_ = has_bounds>
bits::ADDRESS_BITS - GRANULARITY_BITS; std::enable_if_t<!has_bounds_> init(ASM* a)
static constexpr size_t ENTRIES = bits::one_at_bit(COVERED_BITS); {
auto new_body = (a->template reserve<false, false>(ENTRIES * sizeof(T))) static_assert(
.template as_static<T>() has_bounds_ == has_bounds, "Don't set SFINAE template parameter!");
.unsafe_ptr(); static constexpr size_t COVERED_BITS =
bits::ADDRESS_BITS - GRANULARITY_BITS;
static constexpr size_t ENTRIES = bits::one_at_bit(COVERED_BITS);
auto new_body = (a->template reserve<false, false>(ENTRIES * sizeof(T)))
.template as_static<T>()
.unsafe_ptr();
// Ensure bottom page is committed // Ensure bottom page is committed
commit_entry(&new_body[0]); commit_entry(&new_body[0]);
// Set up zero page // Set up zero page
new_body[0] = body[0]; new_body[0] = body[0];
body = new_body; body = new_body;
// TODO this is pretty sparse, should we ignore huge pages for it? // TODO this is pretty sparse, should we ignore huge pages for it?
// madvise(body, size, MADV_NOHUGEPAGE); // madvise(body, size, MADV_NOHUGEPAGE);
}
} }
/** /**