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/*
* Copyright (c) 2016, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "server.h"
#include <unistd.h>
#include <fcntl.h>
typedef struct {
size_t keys;
size_t cow;
monotime cow_updated;
double progress;
childInfoType information_type; /* Type of information */
} child_info_data;
/* Open a child-parent channel used in order to move information about the
* RDB / AOF saving process from the child to the parent (for instance
* the amount of copy on write memory used) */
void openChildInfoPipe(void) {
if (anetPipe(server.child_info_pipe, O_NONBLOCK, 0) == -1) {
/* On error our two file descriptors should be still set to -1,
* but we call anyway closeChildInfoPipe() since can't hurt. */
closeChildInfoPipe();
} else {
server.child_info_nread = 0;
}
}
/* Close the pipes opened with openChildInfoPipe(). */
void closeChildInfoPipe(void) {
if (server.child_info_pipe[0] != -1 ||
server.child_info_pipe[1] != -1)
{
close(server.child_info_pipe[0]);
close(server.child_info_pipe[1]);
server.child_info_pipe[0] = -1;
server.child_info_pipe[1] = -1;
server.child_info_nread = 0;
}
}
/* Send save data to parent. */
void sendChildInfoGeneric(childInfoType info_type, size_t keys, double progress, char *pname) {
if (server.child_info_pipe[1] == -1) return;
static monotime cow_updated = 0;
static uint64_t cow_update_cost = 0;
static size_t cow = 0;
static size_t peak_cow = 0;
static size_t update_count = 0;
static unsigned long long sum_cow = 0;
child_info_data data = {0}; /* zero everything, including padding to satisfy valgrind */
/* When called to report current info, we need to throttle down CoW updates as they
* can be very expensive. To do that, we measure the time it takes to get a reading
* and schedule the next reading to happen not before time*CHILD_COW_COST_FACTOR
* passes. */
monotime now = getMonotonicUs();
if (info_type != CHILD_INFO_TYPE_CURRENT_INFO ||
!cow_updated ||
now - cow_updated > cow_update_cost * CHILD_COW_DUTY_CYCLE)
{
cow = zmalloc_get_private_dirty(-1);
cow_updated = getMonotonicUs();
cow_update_cost = cow_updated - now;
if (cow > peak_cow) peak_cow = cow;
sum_cow += cow;
update_count++;
int cow_info = (info_type != CHILD_INFO_TYPE_CURRENT_INFO);
if (cow || cow_info) {
serverLog(cow_info ? LL_NOTICE : LL_VERBOSE,
"Fork CoW for %s: current %zu MB, peak %zu MB, average %llu MB",
pname, cow>>20, peak_cow>>20, (sum_cow/update_count)>>20);
}
}
data.information_type = info_type;
data.keys = keys;
data.cow = cow;
data.cow_updated = cow_updated;
data.progress = progress;
ssize_t wlen = sizeof(data);
if (write(server.child_info_pipe[1], &data, wlen) != wlen) {
/* Nothing to do on error, this will be detected by the other side. */
}
}
/* Update Child info. */
void updateChildInfo(childInfoType information_type, size_t cow, monotime cow_updated, size_t keys, double progress) {
if (cow > server.stat_current_cow_peak) server.stat_current_cow_peak = cow;
if (information_type == CHILD_INFO_TYPE_CURRENT_INFO) {
server.stat_current_cow_bytes = cow;
server.stat_current_cow_updated = cow_updated;
server.stat_current_save_keys_processed = keys;
if (progress != -1) server.stat_module_progress = progress;
} else if (information_type == CHILD_INFO_TYPE_AOF_COW_SIZE) {
server.stat_aof_cow_bytes = server.stat_current_cow_peak;
} else if (information_type == CHILD_INFO_TYPE_RDB_COW_SIZE) {
server.stat_rdb_cow_bytes = server.stat_current_cow_peak;
} else if (information_type == CHILD_INFO_TYPE_MODULE_COW_SIZE) {
server.stat_module_cow_bytes = server.stat_current_cow_peak;
}
}
/* Read child info data from the pipe.
* if complete data read into the buffer,
* data is stored into *buffer, and returns 1.
* otherwise, the partial data is left in the buffer, waiting for the next read, and returns 0. */
int readChildInfo(childInfoType *information_type, size_t *cow, monotime *cow_updated, size_t *keys, double* progress) {
/* We are using here a static buffer in combination with the server.child_info_nread to handle short reads */
static child_info_data buffer;
ssize_t wlen = sizeof(buffer);
/* Do not overlap */
if (server.child_info_nread == wlen) server.child_info_nread = 0;
int nread = read(server.child_info_pipe[0], (char *)&buffer + server.child_info_nread, wlen - server.child_info_nread);
if (nread > 0) {
server.child_info_nread += nread;
}
/* We have complete child info */
if (server.child_info_nread == wlen) {
*information_type = buffer.information_type;
*cow = buffer.cow;
*cow_updated = buffer.cow_updated;
*keys = buffer.keys;
*progress = buffer.progress;
return 1;
} else {
return 0;
}
}
/* Receive info data from child. */
void receiveChildInfo(void) {
if (server.child_info_pipe[0] == -1) return;
size_t cow;
monotime cow_updated;
size_t keys;
double progress;
childInfoType information_type;
/* Drain the pipe and update child info so that we get the final message. */
while (readChildInfo(&information_type, &cow, &cow_updated, &keys, &progress)) {
updateChildInfo(information_type, cow, cow_updated, keys, progress);
}
}
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