luo980/libuv
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

linux: read load average from /proc/loadavg

Browse Source 
It was reported that uv_loadavg() reports the wrong values inside an
lxc container.

Libuv calls sysinfo(2) but that isn't intercepted by lxc. /proc/loadavg
however is because /proc is a FUSE fs inside the container.

This commit makes libuv try /proc/loadavg first and fall back to
sysinfo(2) in case /proc isn't mounted.

This commit is very similar to commit 3a1be725 ("linux: read free/total
memory from /proc/meminfo") from April 2019.

Fixes: https://github.com/nodejs/node/issues/33791
PR-URL: https://github.com/libuv/libuv/pull/2876
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
This commit is contained in:
Ben Noordhuis 2020-06-12 12:15:38 +02:00
parent 1a89003635
commit 1c22b44380
3 changed files with 21 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
CMakeLists.txt
View File

@ -192,8 +192,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Android")
src/unix/pthread-fixes.c
src/unix/random-getentropy.c
src/unix/random-getrandom.c
src/unix/random-sysctl-linux.c
src/unix/sysinfo-loadavg.c)
src/unix/random-sysctl-linux.c)
endif()
if(APPLE OR CMAKE_SYSTEM_NAME MATCHES "Android|Linux|OS390")
@ -237,8 +236,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
src/unix/linux-syscalls.c
src/unix/procfs-exepath.c
src/unix/random-getrandom.c
src/unix/random-sysctl-linux.c
src/unix/sysinfo-loadavg.c)
src/unix/random-sysctl-linux.c)
endif()
if(CMAKE_SYSTEM_NAME STREQUAL "NetBSD")

6
Makefile.am
View File

@ -386,8 +386,7 @@ libuv_la_SOURCES += src/unix/android-ifaddrs.c \
src/unix/procfs-exepath.c \
src/unix/pthread-fixes.c \
src/unix/random-getrandom.c \
src/unix/random-sysctl-linux.c \
src/unix/sysinfo-loadavg.c
src/unix/random-sysctl-linux.c
endif
if CYGWIN
@ -468,8 +467,7 @@ libuv_la_SOURCES += src/unix/linux-core.c \
src/unix/procfs-exepath.c \
src/unix/proctitle.c \
src/unix/random-getrandom.c \
src/unix/random-sysctl-linux.c \
src/unix/sysinfo-loadavg.c
src/unix/random-sysctl-linux.c
test_run_tests_LDFLAGS += -lutil
endif

17
src/unix/linux-core.c
View File

@ -1084,3 +1084,20 @@ uint64_t uv_get_constrained_memory(void) {
*/
return uv__read_cgroups_uint64("memory", "memory.limit_in_bytes");
}
void uv_loadavg(double avg[3]) {
struct sysinfo info;
char buf[128]; /* Large enough to hold all of /proc/loadavg. */
if (0 == uv__slurp("/proc/loadavg", buf, sizeof(buf)))
if (3 == sscanf(buf, "%lf %lf %lf", &avg[0], &avg[1], &avg[2]))
return;
if (sysinfo(&info) < 0)
return;
avg[0] = (double) info.loads[0] / 65536.0;
avg[1] = (double) info.loads[1] / 65536.0;
avg[2] = (double) info.loads[2] / 65536.0;
}