From: Mel Gorman <mgorman@xxxxxxx> Date: Mon, 14 May 2012 11:56:04 +0100 > On Fri, May 11, 2012 at 01:10:34AM -0400, David Miller wrote: >> From: Mel Gorman <mgorman@xxxxxxx> >> Date: Thu, 10 May 2012 14:54:14 +0100 >> >> > It could happen that all !SOCK_MEMALLOC sockets have buffered so >> > much data that we're over the global rmem limit. This will prevent >> > SOCK_MEMALLOC buffers from receiving data, which will prevent userspace >> > from running, which is needed to reduce the buffered data. >> > >> > Fix this by exempting the SOCK_MEMALLOC sockets from the rmem limit. >> > >> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> >> > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> >> >> This introduces an invariant which I am not so sure is enforced. >> >> With this change it is absolutely required that once a socket >> becomes SOCK_MEMALLOC it must never _ever_ lose that attribute. >> > > This is effectively true. In the NFS case, the flag is cleared on > swapoff after all the entries have been paged in. In the NBD case, > SOCK_MEMALLOC is left set until the socket is destroyed. I'll update the > changelog. Bugs happen, you need to find a way to assert that nobody every does this. Because if a bug is introduced which makes this happen, it will otherwise be very difficult to debug. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>