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/*
Copyright (c) 2006-2009 Z RESEARCH, Inc. <http://www.zresearch.com>
This file is part of GlusterFS.
GlusterFS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3 of the License,
or (at your option) any later version.
GlusterFS is distributed in the hope that 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see
<http://www.gnu.org/licenses/>.
*/
#ifndef __IOT_H
#define __IOT_H
#ifndef _CONFIG_H
#define _CONFIG_H
#include "config.h"
#endif
#include "compat-errno.h"
#include "glusterfs.h"
#include "logging.h"
#include "dict.h"
#include "xlator.h"
#include "common-utils.h"
#include "list.h"
#include <stdlib.h>
#define min(a,b) ((a)<(b)?(a):(b))
#define max(a,b) ((a)>(b)?(a):(b))
struct iot_conf;
struct iot_worker;
struct iot_request;
struct iot_request {
struct list_head list; /* Attaches this request to the list of
requests.
*/
call_stub_t *stub;
};
typedef enum {
IOT_STATE_ACTIVE,
IOT_STATE_EXIT_REQUEST,
IOT_STATE_DEAD
}iot_state_t;
#define iot_worker_active(wrk) ((wrk)->state == IOT_STATE_ACTIVE)
#define MAX_IDLE_SKEW 1000 /* usecs */
#define skew_usec_idle_time(usec) ((usec) + (random () % MAX_IDLE_SKEW))
#define IOT_DEFAULT_IDLE 180 /* In secs. */
#define IOT_MIN_THREADS 2
#define IOT_DEFAULT_THREADS 16
#define IOT_MAX_THREADS 64
#define IOT_SCALING_OFF _gf_false
#define IOT_SCALING_ON _gf_true
#define iot_ordered_scaling_on(conf) ((conf)->o_scaling == IOT_SCALING_ON)
#define iot_unordered_scaling_on(conf) ((conf)->u_scaling == IOT_SCALING_ON)
#define IOT_THREAD_STACK_SIZE ((size_t)(1024*1024))
/* This signifies the max number of outstanding request we're expecting
* at a point for every worker thread.
* For an idea of the memory foot-print, consider at most 16 Bytes per
* iot_request_t on a 64-bit system with another 16 bytes per chunk in the
* header. For 64 slots in the pool, we'll use up 2 KiB, with 64 threads this
* goes up to 128 KiB.
*
* Note that this size defines the size of the per-worker mem pool. The
* advantage is that, we're not only reducing the rate of small iot_request_t
* allocations from the heap but also reducing the contention on the libc heap
* by having a mem pool, though small, for each worker.
*/
#define IOT_REQUEST_MEMPOOL_SIZE 64
struct iot_worker {
struct list_head rqlist; /* List of requests assigned to me. */
struct iot_conf *conf;
int64_t q,dq;
pthread_cond_t dq_cond;
pthread_mutex_t qlock;
int32_t queue_size;
pthread_t thread;
iot_state_t state; /* What state is the thread in. */
int thread_idx; /* Thread's index into the worker
array. Since this will be thread
local data, for ensuring that
number of threads dont fall below
a minimum, we just dont allow
threads with specific indices to
exit. Helps us in eliminating one
place where otherwise a lock
would have been required to update
centralized state inside conf.
*/
struct mem_pool *req_pool; /* iot_request_t's come from here. */
};
struct iot_conf {
int32_t thread_count;
struct iot_worker **workers;
xlator_t *this;
/* Config state for ordered threads. */
pthread_mutex_t otlock; /* Used to sync any state that needs
to be changed by the ordered
threads.
*/
int max_o_threads; /* Max. number of ordered threads */
int min_o_threads; /* Min. number of ordered threads.
Ordered thread count never falls
below this threshold.
*/
int o_idle_time; /* in Secs. The idle time after
which an ordered thread exits.
*/
gf_boolean_t o_scaling; /* Set to IOT_SCALING_OFF if user
does not want thread scaling on
ordered threads. If scaling is
off, io-threads maintains at
least min_o_threads number of
threads and never lets any thread
exit.
*/
struct iot_worker **oworkers; /* Ordered thread pool. */
/* Config state for unordered threads */
pthread_mutex_t utlock; /* Used for scaling un-ordered
threads. */
struct iot_worker **uworkers; /* Un-ordered thread pool. */
int max_u_threads; /* Number of unordered threads will
not be higher than this. */
int min_u_threads; /* Number of unordered threads
should not fall below this value.
*/
int u_idle_time; /* If an unordered thread does not
get a request for this amount of
secs, it should try to die.
*/
gf_boolean_t u_scaling; /* Set to IOT_SCALING_OFF if user
does not want thread scaling on
unordered threads. If scaling is
off, io-threads maintains at
least min_u_threads number of
threads and never lets any thread
exit.
*/
pthread_attr_t w_attr; /* Used to reduce the stack size of
the pthread worker down from the
default of 8MiB.
*/
};
typedef struct iot_conf iot_conf_t;
typedef struct iot_worker iot_worker_t;
typedef struct iot_request iot_request_t;
#endif /* __IOT_H */
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