sharepool介绍

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本文将对sharepool进行概述

接口列表

接口名 功能 备注
sp_group_add_task 向sharepool中添加一个进程 不能用于中断上下文
sp_group_drop 丢弃一个spg 每次使用一个spg后调用

sp_group_add_task

函数声明

sp_group_add_task声明如下：

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/**
 * sp_group_add_task() - Add a process to an share group (sp_group).
 * @pid: the pid of the task to be added.
 * @spg_id: the ID of the sp_group.
 *
 * A thread group can't be added to more than one sp_group.
 *
 * Return: A postive group number for success, -errno on failure.
 *
 * The manually specified ID is between [SPG_ID_MIN, SPG_ID_MAX].
 * The automatically allocated ID is between [SPG_ID_AUTO_MIN, SPG_ID_AUTO_MAX].
 * When negative, the return value is -errno.
 */
int sp_group_add_task(int pid, int spg_id)

流程图

向sharepool组中添加一个进程的整体流程图如下所示：

图片名称

spg id检查

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/* mdc scene hack */
if (enable_mdc_default_group)
    spg_id = mdc_default_group_id;

/* Valid spg id */
if ((spg_id < SPG_ID_MIN || spg_id > SPG_ID_AUTO)
    && spg_id != SPG_ID_DVPP_PASS_THROUGH) {
    pr_err_ratelimited("share pool: task add group failed, invalid group id %d\n", spg_id);
    return -EINVAL;
}

/* In auto spg range, find a usable spg. Here we just find and 
 * test the validation of the spg, we do not use it.
 */
if (spg_id >= SPG_ID_AUTO_MIN && spg_id <= SPG_ID_AUTO_MAX) {
    spg = __sp_find_spg(pid, spg_id);

    if (!spg) {
        pr_err_ratelimited("share pool: spg %d hasn't been created\n", spg_id);
        return -EINVAL;
    }

    down_read(&spg->rw_lock);
    if (!spg_valid(spg)) {
        up_read(&spg->rw_lock);
        pr_err_ratelimited("share pool: task add group failed, group id %d is dead\n", spg_id);
        sp_group_drop(spg);
        return -EINVAL;
    }
    up_read(&spg->rw_lock);
    
    /* We need to drop the spg, see __sp_find_spg, we regard finding 
     * of spg as an occupation action to spg
     */
    sp_group_drop(spg);  
}

/* Auto alloc a new spg between [SPG_ID_AUTO_MAX, SPG_ID_AUTO_MIN]  */

if (spg_id == SPG_ID_AUTO) {
    spg_id = ida_alloc_range(&sp_group_id_ida, SPG_ID_AUTO_MIN,
                             SPG_ID_AUTO_MAX, GFP_ATOMIC);
    if (spg_id < 0) {
        pr_err_ratelimited("share pool: task add group failed, auto generate group id failed\n");
        return spg_id;
    }
    id_newly_generated = true;
}

/* DVPP type spg, we will discuss this later */
if (spg_id == SPG_ID_DVPP_PASS_THROUGH) {
    spg_id = ida_alloc_range(&sp_group_id_ida,
                             SPG_ID_DVPP_PASS_THROUGH_MIN,
                             SPG_ID_DVPP_PASS_THROUGH_MAX, GFP_ATOMIC);
    if (spg_id < 0) {
        pr_err_ratelimited("share pool: task add group failed, DVPP auto generate group id failed\n");
        return spg_id;
    }
    id_newly_generated = true;
}

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