| Message ID | 20231212143250.677668-1-f.ebner@proxmox.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | qemu_init: increase NOFILE soft limit on POSIX | expand |
On Tue, Dec 12, 2023 at 03:32:50PM +0100, Fiona Ebner wrote: > In many configurations, e.g. multiple vNICs with multiple queues or > with many Ceph OSDs, the default soft limit of 1024 is not enough. > QEMU is supposed to work fine with file descriptors >= 1024 and does > not use select() on POSIX. Bump the soft limit to the allowed hard > limit to avoid issues with the aforementioned configurations. > > Of course the limit could be raised from the outside, but the man page > of systemd.exec states about 'LimitNOFILE=': > > > Don't use. > > [...] > > Typically applications should increase their soft limit to the hard > > limit on their own, if they are OK with working with file > > descriptors above 1023, > > Buglink: https://bugzilla.proxmox.com/show_bug.cgi?id=4507 > Signed-off-by: Fiona Ebner <f.ebner@proxmox.com> > --- > include/sysemu/os-posix.h | 1 + > include/sysemu/os-win32.h | 5 +++++ > os-posix.c | 18 ++++++++++++++++++ > system/vl.c | 2 ++ > 4 files changed, 26 insertions(+) > > diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h > index dff32ae185..b881ac6c6f 100644 > --- a/include/sysemu/os-posix.h > +++ b/include/sysemu/os-posix.h > @@ -51,6 +51,7 @@ bool is_daemonized(void); > void os_daemonize(void); > bool os_set_runas(const char *user_id); > void os_set_chroot(const char *path); > +void os_setup_limits(void); > void os_setup_post(void); > int os_mlock(void); > > diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h > index 1047d260cb..106f155037 100644 > --- a/include/sysemu/os-win32.h > +++ b/include/sysemu/os-win32.h > @@ -128,6 +128,11 @@ static inline int os_mlock(void) > return -ENOSYS; > } > > +void os_setup_limits(void) > +{ > + return; > +} > + > #define fsync _commit > > #if !defined(lseek) > diff --git a/os-posix.c b/os-posix.c > index 52ef6990ff..eb55473140 100644 > --- a/os-posix.c > +++ b/os-posix.c > @@ -24,6 +24,7 @@ > */ > > #include "qemu/osdep.h" > +#include <sys/resource.h> > #include <sys/wait.h> > #include <pwd.h> > #include <grp.h> > @@ -256,6 +257,23 @@ void os_daemonize(void) > } > } > > +void os_setup_limits(void) > +{ > + struct rlimit nofile; > + > + if (getrlimit(RLIMIT_NOFILE, &nofile) < 0) { > + warn_report("unable to query NOFILE limit: %s", strerror(errno)); > + return; > + } > + I'd suggest to return here, if cur == max, to avoid the redundant setrlimit call. This will avoid a needless warning message if someone used a strict seccomp filter to block setrlimit, and had raisd NOFILE before QEMU was execd > + nofile.rlim_cur = nofile.rlim_max; > + > + if (setrlimit(RLIMIT_NOFILE, &nofile) < 0) { > + warn_report("unable to set NOFILE limit: %s", strerror(errno)); > + return; > + } > +} > + > void os_setup_post(void) > { > int fd = 0; > diff --git a/system/vl.c b/system/vl.c > index 2bcd9efb9a..6f42f37200 100644 > --- a/system/vl.c > +++ b/system/vl.c > @@ -2774,6 +2774,8 @@ void qemu_init(int argc, char **argv) > error_init(argv[0]); > qemu_init_exec_dir(argv[0]); > > + os_setup_limits(); > + > qemu_init_arch_modules(); > > qemu_init_subsystems(); > -- > 2.39.2 > > > With regards, Daniel
diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h index dff32ae185..b881ac6c6f 100644 --- a/include/sysemu/os-posix.h +++ b/include/sysemu/os-posix.h @@ -51,6 +51,7 @@ bool is_daemonized(void); void os_daemonize(void); bool os_set_runas(const char *user_id); void os_set_chroot(const char *path); +void os_setup_limits(void); void os_setup_post(void); int os_mlock(void); diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h index 1047d260cb..106f155037 100644 --- a/include/sysemu/os-win32.h +++ b/include/sysemu/os-win32.h @@ -128,6 +128,11 @@ static inline int os_mlock(void) return -ENOSYS; } +void os_setup_limits(void) +{ + return; +} + #define fsync _commit #if !defined(lseek) diff --git a/os-posix.c b/os-posix.c index 52ef6990ff..eb55473140 100644 --- a/os-posix.c +++ b/os-posix.c @@ -24,6 +24,7 @@ */ #include "qemu/osdep.h" +#include <sys/resource.h> #include <sys/wait.h> #include <pwd.h> #include <grp.h> @@ -256,6 +257,23 @@ void os_daemonize(void) } } +void os_setup_limits(void) +{ + struct rlimit nofile; + + if (getrlimit(RLIMIT_NOFILE, &nofile) < 0) { + warn_report("unable to query NOFILE limit: %s", strerror(errno)); + return; + } + + nofile.rlim_cur = nofile.rlim_max; + + if (setrlimit(RLIMIT_NOFILE, &nofile) < 0) { + warn_report("unable to set NOFILE limit: %s", strerror(errno)); + return; + } +} + void os_setup_post(void) { int fd = 0; diff --git a/system/vl.c b/system/vl.c index 2bcd9efb9a..6f42f37200 100644 --- a/system/vl.c +++ b/system/vl.c @@ -2774,6 +2774,8 @@ void qemu_init(int argc, char **argv) error_init(argv[0]); qemu_init_exec_dir(argv[0]); + os_setup_limits(); + qemu_init_arch_modules(); qemu_init_subsystems();