Re: [libvirt] [PATCH RFC 32/32] Add nomatch filters when enumerating udev devices

Filter out some subsystems we are not interested in. --- After the netdev cleanups, this speeds up the driver initialization from 18 ms to 13 ms, which is percentually a lot, but neligible in absolute times. This patch uses a negative filter because I could not find an exhaustive list of possible subsystems. A positive filter could be applied to udev_monitor as well. src/node_device/node_device_udev.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c index b46fec6..2e86230 100644 --- a/src/node_device/node_device_udev.c +++ b/src/node_device/node_device_udev.c @@ -1167,13 +1167,34 @@ static int udevProcessDeviceListEntry(struct udev *udev, }

+const char *subsystem_blacklist[] = { + "acpi", "tty", "vc", "i2c", +}; + +static int udevEnumerateAddMatches(struct udev_enumerate *udev_enumerate) +{ + size_t i; + + for (i = 0; i < ARRAY_CARDINALITY(subsystem_blacklist); i++) { + const char *s = subsystem_blacklist[i]; + if (udev_enumerate_add_nomatch_subsystem(udev_enumerate, s) < 0) { + virReportSystemError(errno, "%s", _("failed to add susbsystem filter")); + return -1;

+ } + } + return 0; +} + + static int udevEnumerateDevices(struct udev *udev) { struct udev_enumerate *udev_enumerate = NULL; struct udev_list_entry *list_entry = NULL; - int ret = 0; + int ret = -1; udev_enumerate = udev_enumerate_new(udev); + if (udevEnumerateAddMatches(udev_enumerate) < 0) + goto cleanup; ret = udev_enumerate_scan_devices(udev_enumerate); if (ret != 0) {