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/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can
* be found in the LICENSE file.
*
*/
#pragma once
//
// This is a suballocator for a large extent typically less than 4 GB.
//
// The SKC pipeline will use this for ephemeral host and device memory
// allocations. The lifetime of an allocation is typically
// milliseconds or less and is associated with either a single kernel
// or a sub-pipeline.
//
// Because of this, a relatively small number of allocations (10's)
// will be outstanding at any time so the implementation can
// reasonably be very simplistic and optimize for this case.
//
// Also, if either memory or subbuffer nodes aren't available the
// suballocator will block and pump the pipeline's scheduler until it
// can proceed.
//
// Note that this implementation is single-threaded and the
// suballocator's state may have been altered after pumping the
// scheduler.
//
#include "types.h"
//
// It's practical for the subbuf_id to be either 16 bits or maybe even
// 8 bits if the number of outstanding subbufs is in the thousands (16
// bits) or under 256 (8 bits).
//
typedef skc_ushort skc_subbuf_id_t;
typedef skc_uint skc_subbuf_size_t; // <4GB
// typedef size_t skc_subbuf_size_t; // >4GB
//
//
//
struct skc_subbuf
{
struct skc_subbuf * prev;
struct skc_subbuf * next;
skc_subbuf_size_t size;
skc_subbuf_size_t origin;
skc_uint idx; // ids[] index of subbuf in available state
skc_uint inuse;
};
//
//
//
struct skc_suballocator
{
struct skc_subbuf * subbufs;
skc_subbuf_id_t * ids; // [<-AVAIL-><-empty-><-SPARE->]
struct {
skc_uint avail;
skc_uint spare;
} rem; // inuse = count - (avail + spare)
skc_uint align; // required pow2 alignment
skc_uint count; // number of subbufs
skc_subbuf_size_t size; // size of memory extent
skc_subbuf_size_t total;
char const * name;
};
//
//
//
void
skc_suballocator_create(struct skc_runtime * const runtime,
struct skc_suballocator * const suballocator,
char const * const name,
skc_uint const subbufs,
size_t const align,
size_t const size);
void
skc_suballocator_dispose(struct skc_runtime * const runtime,
struct skc_suballocator * const suballocator);
//
//
//
size_t
skc_suballocator_subbuf_alloc(struct skc_suballocator * const suballocator,
struct skc_scheduler * const scheduler,
size_t const size,
skc_subbuf_id_t * const subbuf_id,
size_t * const subbuf_size);
void
skc_suballocator_subbuf_free(struct skc_suballocator * const suballocator,
skc_subbuf_id_t subbuf_id);
//
//
//
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