nvidia-open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_perf_utils.c

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    Copyright (c) 2016 NVIDIA Corporation

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        The above copyright notice and this permission notice shall be
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    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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#include "uvm_common.h"
#include "uvm_linux.h"
#include "uvm_perf_utils.h"
#include "uvm_kvmalloc.h"

static inline size_t leaves_to_levels(size_t leaf_count)
{
    return ilog2(roundup_pow_of_two(leaf_count)) + 1;
}

// Helper function to compute all the nodes required to store a complete binary tree for the given number of leaves
static inline size_t leaves_to_nodes(size_t leaf_count)
{
    size_t ret = 0;
    do {
        ret += leaf_count;
        leaf_count = (leaf_count == 1)? 0 : (leaf_count + 1) / 2;
    } while (leaf_count > 0);

    return ret;
}

NV_STATUS uvm_perf_tree_init(uvm_perf_tree_t *tree, size_t node_size, size_t leaf_count)
{
    NV_STATUS status;
    size_t bytes;

    status = NV_OK;

    tree->leaf_count      = leaf_count;
    tree->level_count     = leaves_to_levels(leaf_count);
    tree->node_count      = leaves_to_nodes(leaf_count);
    tree->pow2_leaf_count = roundup_pow_of_two(tree->leaf_count);

    bytes = tree->node_count * node_size;

    // With this check we make sure that our shift operations will not overflow
    UVM_ASSERT(tree->level_count <= (sizeof(size_t) * 8 - 1));
    tree->nodes = uvm_kvmalloc_zero(bytes);
    if (!tree->nodes)
        status = NV_ERR_NO_MEMORY;
    return status;
}

void uvm_perf_tree_destroy(uvm_perf_tree_t *tree)
{
    UVM_ASSERT(tree);
    UVM_ASSERT(tree->nodes);

    uvm_kvfree(tree->nodes);
    tree->leaf_count = 0;
    tree->nodes = NULL;
}

void uvm_perf_tree_clear(uvm_perf_tree_t *tree, size_t node_size)
{
    UVM_ASSERT(tree);
    UVM_ASSERT(tree->nodes);

    memset(tree->nodes, 0, tree->node_count * node_size);
}