* [ANN] cmogstored 1.5.0 - a mogstored alternative
@ 2015-11-21 2:58 5% Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2015-11-21 2:58 UTC (permalink / raw)
To: mogile, cmogstored-public
cmogstored is an alternative implementation of the "mogstored" storage
component of MogileFS. cmogstored is implemented in C and does not use
Perl at runtime. cmogstored is the only component you need to install
on a MogileFS storage node.
Changes since 1.4.3:
cmogstored 1.5.0 - vfork, systemd, 416 codes
A bunch of minor changes; most notable is systemd-style socket
activation support. This was easy-to-add since we've always had
socket activation support for nginx-style SIGUSR2 upgrades.
This places no link or runtime dependency on libsystemd, so the
LISTEN_FDS and LISTEN_PID environment variables may be used in other
init systems as well. While I have my own reservations about
systemd itself, I also strongly believe in using socket activation
to prevent downtime. Existing behavior with CMOGSTORED_FD
(used for SIGUSR2 upgrades) is now documented in the manpage and
will always supported.
We've also added vfork support for Linux systems, allowing
faster spawning of iostat if malloc is using too much memory.
Behavior changes:
Bad Range: headers return 416 responses in more cases for invalid
ranges (e.g. miscalculated ranges such as "1--1", while
completely wrong ones (lacking a "bytes=" prefix) are ignored
entirely as in nginx.
Bugfixes:
There are also some cleanups to avoid dying on OOM in more places
on weird systems which trigger OOM. More work on this is ongoing.
Also updates to the latest gnulib.git
commit 71d39c1644762745b94e9449c45bfd716a79a5eb
("autoupdate") along with a change which fixes a memory leak when
people build from cmogstored.git using gnulib
commit c6148bca89e9465fd6ba3a10d273ec4cb58c2dbe
or later ("mountlist: add me_mntroot field on Linux machines").
This memory leak did not affect any released tarballs of cmogstored.
Note, users building from git (as opposed to the tarball) will
need gnulib commit 41d1b6c42641a5b9e21486ca2074198ee7909bd7
("mountlist: add support for deallocating returned list entries")
or later (from July 2013).
There are also various documentation updates and our mailing
list is now readable over NNTP:
nntp://news.public-inbox.org/inbox.comp.file-systems.mogilefs.cmogstored
8 changes since v1.5.0rc0:
doc: document CMOGSTORED_FDS in the manpage
use vfork under Linux before execve
README: update contact information
misc doc updates
add cmogstored manpage to website
Makefile.am: distribute txt2pre in tarball
require newer gnulib for free_mount_entry support
cmogstored 1.5.0 - vfork, systemd, 416 codes
14 changes for 1.5.0rc0:
doc: use "builder" RubyGem to generate Atom feed
dev.c: fail gracefully on out-of-memory errors
do not die on OOM when for mgmt paths
HACKING: update URLs to reduce redirects
http: return 416 errors in more cases for bad Ranges
update .gitignores for latest autotools + gnulib
Rakefile: remove text-only part from the Atom feed
support systemd-style socket activation via environment
set TCP listener options on inherited sockets
doc: add example systemd config files
use free_mount_entry from gnulib instead of rolling our own
fix tmpdir dependency for slow Ruby tests
doc: publish examples directory to website
cmogstored 1.5.0rc1
http://bogomips.org/cmogstored/files/cmogstored-1.5.0.tar.gz
SHA-1: 0581285d7104ff418eed853cfbd94ab08bba4951
SHA-256: b83b954874ef201b6e6616ec3e60f517c6a01f7bc6eda1fbb3901558e34c1388
* homepage: http://bogomips.org/cmogstored/README
* git clone git://bogomips.org/cmogstored.git
* cgit: http://bogomips.org/cmogstored.git
* gitweb: http://repo.or.cz/w/cmogstored.git
* list: cmogstored-public@bogomips.org (subscription optional)
* archives: http://bogomips.org/cmogstored-public/
* nntp://news.public-inbox.org/inbox.comp.file-systems.mogilefs.cmogstored
--
EW
^ permalink raw reply [relevance 5%]
* [PATCH] use vfork under Linux before execve
@ 2015-11-13 23:13 7% Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2015-11-13 23:13 UTC (permalink / raw)
To: cmogstored-public
Given the prevalance of gigantic VM footprints due to current glibc
malloc and our potentially large number of threads, vfork can speed
up fork used for spawning iostat and SIGUSR2 upgrades.
vfork only pauses the spawning thread, so it will not affect other
I/O threads used in cmogstored; only the non-performance-critical
master thread.
Swapping 'fork()' for 'vfork()' in the following C test program
should show a large speedup under Linux.
Changing FILL to increase or decrease memory usage will respectively
decrease or increase performance improvement gain from vfork over
fork..
-----------------------------8<-------------------------
/* gcc -o x x.c -Wall -O2 -lpthread && ./x */
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <pthread.h>
#include <poll.h>
#include <stdio.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <string.h>
#define FILL (1024 * 1024)
static void *thfunc(void *p)
{
void *ptr = malloc(FILL);
memset(ptr, 1, FILL);
poll(0, 0, -1);
return 0;
}
int main(void)
{
long i;
void *ptr = malloc(FILL);
memset(ptr, 1, FILL);
for (i = 0; i < 100; i++) {
pthread_t th;
pthread_create(&th, 0, thfunc, (void *)i);
}
poll(0, 0, 1000);
for (i = 0; i < 100; i++) {
/* swapping fork with vfork increases performance on Linux */
pid_t pid = fork();
if (pid < 0) {
fprintf(stderr, "ERROR: forking %m\n");
return 1;
}
if (pid == 0) {
char *argv[] = { "/bin/true", 0 };
char *env[] = { 0 };
execve(argv[0], argv, env);
return 1;
} else {
int s;
waitpid(pid, &s, 0);
}
}
return 0;
}
---
cmogstored.h | 10 ++++++++++
configure.ac | 1 +
iostat_process.c | 6 +++---
upgrade.c | 8 +++++---
4 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/cmogstored.h b/cmogstored.h
index 5aa7c01..4bb0716 100644
--- a/cmogstored.h
+++ b/cmogstored.h
@@ -360,6 +360,16 @@ void mog_oom_if_null(const void *);
#define warn(...) error(0, 0, __VA_ARGS__)
+/*
+ * vfork is poorly-specified, but at least on Linux it improves
+ * performance when used for spawning iostat processes
+ */
+#if defined(HAVE_VFORK) && defined(__linux__)
+# define mog_fork_for_exec() vfork()
+#else
+# define mog_fork_for_exec() fork()
+#endif
+
/* maxconns.c */
void mog_set_maxconns(unsigned long);
diff --git a/configure.ac b/configure.ac
index 8bd98e2..0d551c3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -51,6 +51,7 @@ AC_CHECK_FUNCS([ioctl])
AC_CHECK_FUNCS([sendfile])
AC_CHECK_FUNCS([open_memstream])
AC_CHECK_FUNCS([posix_fadvise])
+AC_CHECK_FUNCS([vfork])
dnl need LIBS=-lfreebsd-glue (but not CFLAGS=-I/usr/include/freebsd)
AC_CHECK_FUNCS([bsd_sendfile])
diff --git a/iostat_process.c b/iostat_process.c
index 90a291f..4d7dfbf 100644
--- a/iostat_process.c
+++ b/iostat_process.c
@@ -65,7 +65,7 @@ static void dup2_or_die(int oldfd, int newfd, const char *errdesc)
if (rc < 0) {
syslog(LOG_CRIT, "dup2(%s) failed: %m", errdesc);
- abort();
+ _exit(1);
}
}
@@ -96,7 +96,7 @@ static pid_t iostat_fork_exec(int out_fd)
cmd = exec_cmd(cmd);
- iostat_pid = fork();
+ iostat_pid = mog_fork_for_exec();
if (iostat_pid < 0) {
syslog(LOG_ERR, "fork() for iostat failed: %m");
} else if (iostat_pid > 0) {
@@ -111,7 +111,7 @@ static pid_t iostat_fork_exec(int out_fd)
mog_intr_enable();
execl("/bin/sh", "sh", "-c", cmd, (char *)NULL);
syslog(LOG_CRIT, "execl(%s) failed: %m", cmd);
- abort();
+ _exit(1);
}
mog_free(cmd);
return iostat_pid;
diff --git a/upgrade.c b/upgrade.c
index 1311ebe..82a7b28 100644
--- a/upgrade.c
+++ b/upgrade.c
@@ -125,13 +125,14 @@ pid_t mog_upgrade_spawn(void)
assert(dst[bytes - 1] == ',' && "not comma-terminated no listeners?");
dst[bytes - 1] = '\0'; /* kill the last comma */
+ start.envp[0] = dst;
- pid = fork();
+ pid = mog_fork_for_exec();
if (pid == 0) {
- start.envp[0] = dst;
mog_svc_upgrade_prepare();
execve(execfile, start.argv, start.envp);
- die_errno("execve %s", execfile);
+ syslog(LOG_ERR, "execve %s failed for upgrade: %m", execfile);
+ _exit(2);
} else if (pid > 0) {
mog_process_register(pid, MOG_PROC_UPGRADE);
syslog(LOG_INFO, "upgrade spawned PID:%d", pid);
@@ -143,6 +144,7 @@ out:
/* find_in_path does not malloc if output == input */
if (execfile != start.argv[0])
mog_free(execfile);
+ start.envp[0] = 0;
free(dst);
return pid;
--
EW
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