diff options
| -rw-r--r-- | src/util/SliceBuffer.hxx | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/src/util/SliceBuffer.hxx b/src/util/SliceBuffer.hxx index 9ddad6b3d..1f5ff873d 100644 --- a/src/util/SliceBuffer.hxx +++ b/src/util/SliceBuffer.hxx @@ -48,6 +48,13 @@ class SliceBuffer { const unsigned n_max; /** + * The number of slices that are initialized. This is used to + * avoid page faulting on the new allocation, so the kernel + * does not need to reserve physical memory pages. + */ + unsigned n_initialized; + + /** * The number of slices currently allocated. */ unsigned n_allocated; @@ -61,15 +68,9 @@ class SliceBuffer { public: SliceBuffer(unsigned _count) - :n_max(_count), n_allocated(0), - data(g_new(Slice, n_max)), available(data) { + :n_max(_count), n_initialized(0), n_allocated(0), + data(g_new(Slice, n_max)), available(nullptr) { assert(n_max > 0); - - Slice *const last = data + n_max - 1; - for (Slice *slice = data; slice != last; ++slice) - slice->next = slice + 1; - - last->next = nullptr; } ~SliceBuffer() { @@ -97,12 +98,18 @@ public: template<typename... Args> T *Allocate(Args&&... args) { - assert(n_allocated <= n_max); + assert(n_initialized <= n_max); + assert(n_allocated <= n_initialized); if (available == nullptr) { - /* out of (internal) memory, buffer is full */ - assert(n_allocated == n_max); - return nullptr; + if (n_initialized == n_max) { + /* out of (internal) memory, buffer is full */ + assert(n_allocated == n_max); + return nullptr; + } + + available = &data[n_initialized++]; + available->next = nullptr; } /* allocate a slice */ @@ -115,8 +122,9 @@ public: } void Free(T *value) { + assert(n_initialized <= n_max); assert(n_allocated > 0); - assert(n_allocated <= n_max); + assert(n_allocated <= n_initialized); Slice *slice = reinterpret_cast<Slice *>(value); assert(slice >= data && slice < data + n_max); |