call-path.c

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/*
 * call-path.h: Manipulate a tree data structure containing function call paths
 * Copyright (c) 2014, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/rbtree.h>
#include <linux/list.h>

#include "util.h"
#include "call-path.h"

static void call_path__init(struct call_path *cp, struct call_path *parent,
                struct symbol *sym, u64 ip, bool in_kernel)
{
    cp->parent = parent;
    cp->sym = sym;
    cp->ip = sym ? 0 : ip;
    cp->db_id = 0;
    cp->in_kernel = in_kernel;
    RB_CLEAR_NODE(&cp->rb_node);
    cp->children = RB_ROOT;
}

struct call_path_root *call_path_root__new(void)
{
    struct call_path_root *cpr;

    cpr = zalloc(sizeof(struct call_path_root));
    if (!cpr)
        return NULL;
    call_path__init(&cpr->call_path, NULL, NULL, 0, false);
    INIT_LIST_HEAD(&cpr->blocks);
    return cpr;
}

void call_path_root__free(struct call_path_root *cpr)
{
    struct call_path_block *pos, *n;

    list_for_each_entry_safe(pos, n, &cpr->blocks, node) {
        list_del(&pos->node);
        free(pos);
    }
    free(cpr);
}

static struct call_path *call_path__new(struct call_path_root *cpr,
                    struct call_path *parent,
                    struct symbol *sym, u64 ip,
                    bool in_kernel)
{
    struct call_path_block *cpb;
    struct call_path *cp;
    size_t n;

    if (cpr->next < cpr->sz) {
        cpb = list_last_entry(&cpr->blocks, struct call_path_block,
                      node);
    } else {
        cpb = zalloc(sizeof(struct call_path_block));
        if (!cpb)
            return NULL;
        list_add_tail(&cpb->node, &cpr->blocks);
        cpr->sz += CALL_PATH_BLOCK_SIZE;
    }

    n = cpr->next++ & CALL_PATH_BLOCK_MASK;
    cp = &cpb->cp[n];

    call_path__init(cp, parent, sym, ip, in_kernel);

    return cp;
}

struct call_path *call_path__findnew(struct call_path_root *cpr,
                     struct call_path *parent,
                     struct symbol *sym, u64 ip, u64 ks)
{
    struct rb_node **p;
    struct rb_node *node_parent = NULL;
    struct call_path *cp;
    bool in_kernel = ip >= ks;

    if (sym)
        ip = 0;

    if (!parent)
        return call_path__new(cpr, parent, sym, ip, in_kernel);

    p = &parent->children.rb_node;
    while (*p != NULL) {
        node_parent = *p;
        cp = rb_entry(node_parent, struct call_path, rb_node);

        if (cp->sym == sym && cp->ip == ip)
            return cp;

        if (sym < cp->sym || (sym == cp->sym && ip < cp->ip))
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }

    cp = call_path__new(cpr, parent, sym, ip, in_kernel);
    if (!cp)
        return NULL;

    rb_link_node(&cp->rb_node, node_parent, p);
    rb_insert_color(&cp->rb_node, &parent->children);

    return cp;
}