Mercurial > hg > nginx-quic
view src/os/unix/ngx_freebsd_init.c @ 4667:d05ab8793a69 stable-1.2
Merge of r4622, r4623: balancing changes.
*) Upstream: smooth weighted round-robin balancing.
For edge case weights like { 5, 1, 1 } we now produce { a, a, b, a, c, a, a }
sequence instead of { c, b, a, a, a, a, a } produced previously.
Algorithm is as follows: on each peer selection we increase current_weight
of each eligible peer by its weight, select peer with greatest current_weight
and reduce its current_weight by total number of weight points distributed
among peers.
In case of { 5, 1, 1 } weights this gives the following sequence of
current_weight's:
a b c
0 0 0 (initial state)
5 1 1 (a selected)
-2 1 1
3 2 2 (a selected)
-4 2 2
1 3 3 (b selected)
1 -4 3
6 -3 4 (a selected)
-1 -3 4
4 -2 5 (c selected)
4 -2 -2
9 -1 -1 (a selected)
2 -1 -1
7 0 0 (a selected)
0 0 0
To preserve weight reduction in case of failures the effective_weight
variable was introduced, which usually matches peer's weight, but is
reduced temporarily on peer failures.
This change also fixes loop with backup servers and proxy_next_upstream
http_404 (ticket #47), and skipping alive upstreams in some cases if there
are multiple dead ones (ticket #64).
*) Upstream: fixed ip_hash rebalancing with the "down" flag.
Due to weight being set to 0 for down peers, order of peers after sorting
wasn't the same as without the "down" flag (with down peers at the end),
resulting in client rebalancing for clients on other servers. The only
rebalancing which should happen after adding "down" to a server is one
for clients on the server.
The problem was introduced in r1377 (which fixed endless loop by setting
weight to 0 for down servers). The loop is no longer possible with new
smooth algorithm, so preserving original weight is safe.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 04 Jun 2012 11:21:58 +0000 |
parents | d620f497c50f |
children | f329a1d2127b |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> /* FreeBSD 3.0 at least */ char ngx_freebsd_kern_ostype[16]; char ngx_freebsd_kern_osrelease[128]; int ngx_freebsd_kern_osreldate; int ngx_freebsd_hw_ncpu; int ngx_freebsd_kern_ipc_somaxconn; u_long ngx_freebsd_net_inet_tcp_sendspace; /* FreeBSD 4.9 */ int ngx_freebsd_machdep_hlt_logical_cpus; ngx_uint_t ngx_freebsd_sendfile_nbytes_bug; ngx_uint_t ngx_freebsd_use_tcp_nopush; ngx_uint_t ngx_debug_malloc; static ngx_os_io_t ngx_freebsd_io = { ngx_unix_recv, ngx_readv_chain, ngx_udp_unix_recv, ngx_unix_send, #if (NGX_HAVE_SENDFILE) ngx_freebsd_sendfile_chain, NGX_IO_SENDFILE #else ngx_writev_chain, 0 #endif }; typedef struct { char *name; void *value; size_t size; ngx_uint_t exists; } sysctl_t; sysctl_t sysctls[] = { { "hw.ncpu", &ngx_freebsd_hw_ncpu, sizeof(ngx_freebsd_hw_ncpu), 0 }, { "machdep.hlt_logical_cpus", &ngx_freebsd_machdep_hlt_logical_cpus, sizeof(ngx_freebsd_machdep_hlt_logical_cpus), 0 }, { "net.inet.tcp.sendspace", &ngx_freebsd_net_inet_tcp_sendspace, sizeof(ngx_freebsd_net_inet_tcp_sendspace), 0 }, { "kern.ipc.somaxconn", &ngx_freebsd_kern_ipc_somaxconn, sizeof(ngx_freebsd_kern_ipc_somaxconn), 0 }, { NULL, NULL, 0, 0 } }; void ngx_debug_init() { #if (NGX_DEBUG_MALLOC) #if __FreeBSD_version >= 500014 _malloc_options = "J"; #else malloc_options = "J"; #endif ngx_debug_malloc = 1; #else char *mo; mo = getenv("MALLOC_OPTIONS"); if (mo && ngx_strchr(mo, 'J')) { ngx_debug_malloc = 1; } #endif } ngx_int_t ngx_os_specific_init(ngx_log_t *log) { int version; size_t size; ngx_err_t err; ngx_uint_t i; size = sizeof(ngx_freebsd_kern_ostype); if (sysctlbyname("kern.ostype", ngx_freebsd_kern_ostype, &size, NULL, 0) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sysctlbyname(kern.ostype) failed"); if (ngx_errno != NGX_ENOMEM) { return NGX_ERROR; } ngx_freebsd_kern_ostype[size - 1] = '\0'; } size = sizeof(ngx_freebsd_kern_osrelease); if (sysctlbyname("kern.osrelease", ngx_freebsd_kern_osrelease, &size, NULL, 0) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sysctlbyname(kern.osrelease) failed"); if (ngx_errno != NGX_ENOMEM) { return NGX_ERROR; } ngx_freebsd_kern_osrelease[size - 1] = '\0'; } size = sizeof(int); if (sysctlbyname("kern.osreldate", &ngx_freebsd_kern_osreldate, &size, NULL, 0) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sysctlbyname(kern.osreldate) failed"); return NGX_ERROR; } version = ngx_freebsd_kern_osreldate; #if (NGX_HAVE_SENDFILE) /* * The determination of the sendfile() "nbytes bug" is complex enough. * There are two sendfile() syscalls: a new #393 has no bug while * an old #336 has the bug in some versions and has not in others. * Besides libc_r wrapper also emulates the bug in some versions. * There is no way to say exactly if syscall #336 in FreeBSD circa 4.6 * has the bug. We use the algorithm that is correct at least for * RELEASEs and for syscalls only (not libc_r wrapper). * * 4.6.1-RELEASE and below have the bug * 4.6.2-RELEASE and above have the new syscall * * We detect the new sendfile() syscall available at the compile time * to allow an old binary to run correctly on an updated FreeBSD system. */ #if (__FreeBSD__ == 4 && __FreeBSD_version >= 460102) \ || __FreeBSD_version == 460002 || __FreeBSD_version >= 500039 /* a new syscall without the bug */ ngx_freebsd_sendfile_nbytes_bug = 0; #else /* an old syscall that may have the bug */ ngx_freebsd_sendfile_nbytes_bug = 1; #endif #endif /* NGX_HAVE_SENDFILE */ if ((version < 500000 && version >= 440003) || version >= 500017) { ngx_freebsd_use_tcp_nopush = 1; } for (i = 0; sysctls[i].name; i++) { size = sysctls[i].size; if (sysctlbyname(sysctls[i].name, sysctls[i].value, &size, NULL, 0) == 0) { sysctls[i].exists = 1; continue; } err = ngx_errno; if (err == NGX_ENOENT) { continue; } ngx_log_error(NGX_LOG_ALERT, log, err, "sysctlbyname(%s) failed", sysctls[i].name); return NGX_ERROR; } if (ngx_freebsd_machdep_hlt_logical_cpus) { ngx_ncpu = ngx_freebsd_hw_ncpu / 2; } else { ngx_ncpu = ngx_freebsd_hw_ncpu; } if (version < 600008 && ngx_freebsd_kern_ipc_somaxconn > 32767) { ngx_log_error(NGX_LOG_ALERT, log, 0, "sysctl kern.ipc.somaxconn must be less than 32768"); return NGX_ERROR; } ngx_tcp_nodelay_and_tcp_nopush = 1; ngx_os_io = ngx_freebsd_io; return NGX_OK; } void ngx_os_specific_status(ngx_log_t *log) { u_long value; ngx_uint_t i; ngx_log_error(NGX_LOG_NOTICE, log, 0, "OS: %s %s", ngx_freebsd_kern_ostype, ngx_freebsd_kern_osrelease); #ifdef __DragonFly_version ngx_log_error(NGX_LOG_NOTICE, log, 0, "kern.osreldate: %d, built on %d", ngx_freebsd_kern_osreldate, __DragonFly_version); #else ngx_log_error(NGX_LOG_NOTICE, log, 0, "kern.osreldate: %d, built on %d", ngx_freebsd_kern_osreldate, __FreeBSD_version); #endif for (i = 0; sysctls[i].name; i++) { if (sysctls[i].exists) { if (sysctls[i].size == sizeof(long)) { value = *(long *) sysctls[i].value; } else { value = *(int *) sysctls[i].value; } ngx_log_error(NGX_LOG_NOTICE, log, 0, "%s: %l", sysctls[i].name, value); } } }