On Wed, Jun 20, 2012 at 02:04:52PM +0200, Eric Dumazet wrote: > On Wed, 2012-06-20 at 12:44 +0100, Mel Gorman wrote: > > Commit [bad43ca8: net: introduce skb_try_coalesce()] introduced an > > optimisation to coalesce skbs to reduce memory usage and cache line > > misses. In the case where the socket is used for swapping this can result > > in a warning like the following. > > > > [ 110.476565] nbd0: page allocation failure: order:0, mode:0x20 > > [ 110.476568] Pid: 2714, comm: nbd0 Not tainted 3.5.0-rc2-swapnbd-v12r2-slab #3 > > [ 110.476569] Call Trace: > > [ 110.476573] [<ffffffff811042d3>] warn_alloc_failed+0xf3/0x160 > > [ 110.476578] [<ffffffff81107c92>] __alloc_pages_nodemask+0x6e2/0x930 > > > > <SNIP > > > > > This makes absolutely no sense to me. > > This patch changes input path, while your stack trace is about output > path and a packet being fragmented. > The intention was to avoid any coalescing in the input path due to avoid packets that "were held back due to TCP_CORK or attempt at coalescing tiny packet". I recognise that it is clumsy and will take the approach instead of having __tcp_push_pending_frames() use sk_gfp_atomic() in the output path. Thanks. -- Mel Gorman SUSE Labs -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>