The socket receive buffer turned out to be too small for real world systems. Use the same size as udevd to be on the safe side. As this is just a limit and the memory is not allocated by the kernel until really needed there is actually no memory wasted.
Signed-off-by: Jan Klötzke <j...@kloetzke.net> --- util-linux/mdev.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/util-linux/mdev.c b/util-linux/mdev.c index 207a112c1..4e3299d22 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -1155,9 +1155,21 @@ static void initial_scan(char *temp) #if ENABLE_FEATURE_MDEV_DAEMON -/* uevent applet uses 16k buffer, and mmaps it before every read */ -# define BUFFER_SIZE (2 * 1024) -# define RCVBUF (2 * 1024 * 1024) +/* + * The kernel (as of v5.4) will pass up to 32 environment variables with a + * total of 2kiB on each event. On top of that the action string and device + * path are added. Using a 3kiB buffer for the event should suffice in any + * case. + * + * As far as the socket receive buffer size is concerned 2MiB proved to be too + * small (see [1]). Udevd seems to use a whooping 128MiB. The socket receive + * buffer size is just a resource limit. The buffers are allocated lazily so + * the memory is not wasted. + * + * [1] http://lists.busybox.net/pipermail/busybox/2019-December/087665.html + */ +# define BUFFER_SIZE (3 * 1024) +# define RCVBUF (128 * 1024 * 1024) # define MAX_ENV 32 static void daemon_loop(char *temp, int fd) -- 2.20.1 _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
