On Wed, May 18, 2016 at 12:29 PM, Neil Horman <nhor...@tuxdriver.com> wrote: > On Wed, May 18, 2016 at 10:57:21AM -0700, Alexander Duyck wrote: >> On Wed, May 18, 2016 at 9:01 AM, Eric Dumazet <eric.duma...@gmail.com> wrote: >> > On Wed, 2016-05-18 at 11:25 -0400, Neil Horman wrote: >> >> Noticed an allocation failure in a network driver the other day on a 32 >> >> bit >> >> system: >> >> >> >> DMA-API: debugging out of memory - disabling >> >> bnx2fc: adapter_lookup: hba NULL >> >> lldpad: page allocation failure. order:0, mode:0x4120 >> >> Pid: 4556, comm: lldpad Not tainted 2.6.32-639.el6.i686.debug #1 >> >> Call Trace: >> >> [<c08a4086>] ? printk+0x19/0x23 >> >> [<c05166a4>] ? __alloc_pages_nodemask+0x664/0x830 >> >> [<c0649d02>] ? free_object+0x82/0xa0 >> >> [<fb4e2c9b>] ? ixgbe_alloc_rx_buffers+0x10b/0x1d0 [ixgbe] >> >> [<fb4e2fff>] ? ixgbe_configure_rx_ring+0x29f/0x420 [ixgbe] >> >> [<fb4e228c>] ? ixgbe_configure_tx_ring+0x15c/0x220 [ixgbe] >> >> [<fb4e3709>] ? ixgbe_configure+0x589/0xc00 [ixgbe] >> >> [<fb4e7be7>] ? ixgbe_open+0xa7/0x5c0 [ixgbe] >> >> [<fb503ce6>] ? ixgbe_init_interrupt_scheme+0x5b6/0x970 [ixgbe] >> >> [<fb4e8e54>] ? ixgbe_setup_tc+0x1a4/0x260 [ixgbe] >> >> [<fb505a9f>] ? ixgbe_dcbnl_set_state+0x7f/0x90 [ixgbe] >> >> [<c088d80d>] ? dcb_doit+0x10ed/0x16d0 >> >> ... >> > >> > >> > Well, maybe this call site (via ixgbe_configure_rx_ring()) should be >> > using GFP_KERNEL instead of GFP_ATOMIC. >> >> The problem is the ixgbe driver is using the same function for >> allocating memory in the softirq and in the init. As such it has to >> default to GFP_ATOMIC so that it doesn't screw up the NAPI allocation >> case. >> > > I suppose a happy medium would be to extend dev_alloc_pages to accept a gfp > argument, and then have the function itself only set __GFP_NOWARN, if ATOMIC > is > also set?
Why bother? I really think Eric's patch is the way to go. We can already pass gfp flags to __dev_alloc_pages so if we need to pass flags we can use that. Otherwise for the users of dev_alloc_page and dev_alloc_pages we can just pass GFP_ATOMIC | __GFP_NOWARN like Eric did in his example patch. - Alex
