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view auto/os/linux @ 7281:bd6563e81cea
Limit req: improved handling of negative times.
Negative times can appear since workers only update time on an event
loop iteration start. If a worker was blocked for a long time during
an event loop iteration, it is possible that another worker already
updated the time stored in the node. As such, time since last update
of the node (ms) will be negative.
Previous code used ngx_abs(ms) in the calculations. That is, negative
times were effectively treated as positive ones. As a result, it was
not possible to maintain high request rates, where the same node can be
updated multiple times from during an event loop iteration.
In particular, this affected setups with many SSL handshakes, see
http://mailman.nginx.org/pipermail/nginx/2018-May/056291.html.
Fix is to only update the last update time stored in the node if the
new time is larger than previously stored one. If a future time is
stored in the node, we preserve this time as is.
To prevent breaking things on platforms without monotonic time available
if system time is updated backwards, a safety limit of 60 seconds is
used. If the time stored in the node is more than 60 seconds in the future,
we assume that the time was changed backwards and update lr->last
to the current time.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 30 May 2018 15:40:34 +0300 |
parents | 7f28b61c92f0 |
children | f7e79596baf2 |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. have=NGX_LINUX . auto/have_headers CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $LINUX_DEPS" CORE_SRCS="$UNIX_SRCS $LINUX_SRCS" ngx_spacer=' ' cc_aux_flags="$CC_AUX_FLAGS" CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64" # Linux kernel version version=$((`uname -r \ | sed -n -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/ \ \1*256*256+\2*256+\3/p' \ -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/\1*256*256+\2*256/p'`)) version=${version:-0} # posix_fadvise64() had been implemented in 2.5.60 if [ $version -lt 132412 ]; then have=NGX_HAVE_POSIX_FADVISE . auto/nohave fi # epoll, EPOLLET version ngx_feature="epoll" ngx_feature_name="NGX_HAVE_EPOLL" ngx_feature_run=yes ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLOUT|EPOLLET; ee.data.ptr = NULL; (void) ee; efd = epoll_create(100); if (efd == -1) return 1;" . auto/feature if [ $ngx_found = yes ]; then have=NGX_HAVE_CLEAR_EVENT . auto/have CORE_SRCS="$CORE_SRCS $EPOLL_SRCS" EVENT_MODULES="$EVENT_MODULES $EPOLL_MODULE" EVENT_FOUND=YES # EPOLLRDHUP appeared in Linux 2.6.17, glibc 2.8 ngx_feature="EPOLLRDHUP" ngx_feature_name="NGX_HAVE_EPOLLRDHUP" ngx_feature_run=no ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0, fd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLRDHUP|EPOLLET; ee.data.ptr = NULL; epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)" . auto/feature # EPOLLEXCLUSIVE appeared in Linux 4.5, glibc 2.24 ngx_feature="EPOLLEXCLUSIVE" ngx_feature_name="NGX_HAVE_EPOLLEXCLUSIVE" ngx_feature_run=no ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0, fd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLEXCLUSIVE; ee.data.ptr = NULL; epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)" . auto/feature fi # O_PATH and AT_EMPTY_PATH were introduced in 2.6.39, glibc 2.14 ngx_feature="O_PATH" ngx_feature_name="NGX_HAVE_O_PATH" ngx_feature_run=no ngx_feature_incs="#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int fd; struct stat sb; fd = openat(AT_FDCWD, \".\", O_PATH|O_DIRECTORY|O_NOFOLLOW); if (fstatat(fd, \"\", &sb, AT_EMPTY_PATH) != 0) return 1" . auto/feature # sendfile() CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE" ngx_feature="sendfile()" ngx_feature_name="NGX_HAVE_SENDFILE" ngx_feature_run=yes ngx_feature_incs="#include <sys/sendfile.h> #include <errno.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int s = 0, fd = 1; ssize_t n; off_t off = 0; n = sendfile(s, fd, &off, 1); if (n == -1 && errno == ENOSYS) return 1" . auto/feature if [ $ngx_found = yes ]; then CORE_SRCS="$CORE_SRCS $LINUX_SENDFILE_SRCS" fi # sendfile64() CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64" ngx_feature="sendfile64()" ngx_feature_name="NGX_HAVE_SENDFILE64" ngx_feature_run=yes ngx_feature_incs="#include <sys/sendfile.h> #include <errno.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int s = 0, fd = 1; ssize_t n; off_t off = 0; n = sendfile(s, fd, &off, 1); if (n == -1 && errno == ENOSYS) return 1" . auto/feature ngx_include="sys/prctl.h"; . auto/include # prctl(PR_SET_DUMPABLE) ngx_feature="prctl(PR_SET_DUMPABLE)" ngx_feature_name="NGX_HAVE_PR_SET_DUMPABLE" ngx_feature_run=yes ngx_feature_incs="#include <sys/prctl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) return 1" . auto/feature # prctl(PR_SET_KEEPCAPS) ngx_feature="prctl(PR_SET_KEEPCAPS)" ngx_feature_name="NGX_HAVE_PR_SET_KEEPCAPS" ngx_feature_run=yes ngx_feature_incs="#include <sys/prctl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) return 1" . auto/feature # capabilities ngx_feature="capabilities" ngx_feature_name="NGX_HAVE_CAPABILITIES" ngx_feature_run=no ngx_feature_incs="#include <linux/capability.h> #include <sys/syscall.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="struct __user_cap_data_struct data; struct __user_cap_header_struct header; header.version = _LINUX_CAPABILITY_VERSION_1; data.effective = CAP_TO_MASK(CAP_NET_RAW); data.permitted = 0; (void) SYS_capset" . auto/feature # crypt_r() ngx_feature="crypt_r()" ngx_feature_name="NGX_HAVE_GNU_CRYPT_R" ngx_feature_run=no ngx_feature_incs="#include <crypt.h>" ngx_feature_path= ngx_feature_libs=-lcrypt ngx_feature_test="struct crypt_data cd; crypt_r(\"key\", \"salt\", &cd);" . auto/feature ngx_include="sys/vfs.h"; . auto/include CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"