Mercurial > hg > nginx
view auto/endianness @ 6080:4296627f385a stable-1.6
Core: fixed a race resulting in extra sem_post()'s.
The mtx->wait counter was not decremented if we were able to obtain the lock
right after incrementing it. This resulted in unneeded sem_post() calls,
eventually leading to EOVERFLOW errors being logged, "sem_post() failed
while wake shmtx (75: Value too large for defined data type)".
To close the race, mtx->wait is now decremented if we obtain the lock right
after incrementing it in ngx_shmtx_lock(). The result can become -1 if a
concurrent ngx_shmtx_unlock() decrements mtx->wait before the added code does.
However, that only leads to one extra iteration in the next call of
ngx_shmtx_lock().
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 04 Feb 2015 16:22:43 +0300 |
parents | 434548349838 |
children | 7ec809b579d7 |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. echo $ngx_n "checking for system byte ordering ...$ngx_c" echo >> $NGX_ERR echo "checking for system byte ordering" >> $NGX_ERR cat << END > $NGX_AUTOTEST.c int main() { int i = 0x11223344; char *p; p = (char *) &i; if (*p == 0x44) return 0; return 1; } END ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \ -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs" eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1" if [ -x $NGX_AUTOTEST ]; then if $NGX_AUTOTEST >/dev/null 2>&1; then echo " little endian" have=NGX_HAVE_LITTLE_ENDIAN . auto/have else echo " big endian" fi rm -rf $NGX_AUTOTEST* else rm -rf $NGX_AUTOTEST* echo echo "$0: error: cannot detect system byte ordering" exit 1 fi