Mike Christie wrote: > Peter Zijlstra wrote: >> On Thu, 2006-09-14 at 22:35 +0200, Peter Zijlstra wrote: >>> On Thu, 2006-09-14 at 14:22 -0500, Mike Christie wrote: >>>>> I thought I found allocations in that path, lemme search... >>>>> found this: >>>>> >>>>> iscsi_tcp_data_recv() >>>>> iscsi_data_rescv() >>>>> iscsi_complete_pdu() >>>>> __iscsi_complete_pdu() >>>>> iscsi_recv_pdu() >>>>> alloc_skb( GFP_ATOMIC); >>>>> >>>> You are right that is for the netlink interface. Could we move the >>>> PF_MEMALLOC setting and clearing to iscsi_recv_pdu and and add it to >>>> iscsi_conn_error in scsi_transport_iscsi.c so that iscsi_iser and >>>> qla4xxx will have it set when they need it. I will send a patch for this >>>> along with a way to have the netlink sock vmio set for all iscsi drivers >>>> that need it. >>> I already have such a patch, look at: >>> http://programming.kicks-ass.net/kernel-patches/vm_deadlock/current/iscsi_vmio.patch >>> >>> but what conditional do you want to use for PF_MEMALLOC, an >>> unconditional setting will be highly unpopular. >>> >>> Hmm, perhaps you could key it of sk_has_vmio(nls)... >> On second thought, not such a good idea, that will still be too course. >> You only want to force feed stuff originating from >> sk_has_vmio(iscsi_tcp_conn->sock->sk) connections, not all >> connectections as soon as there is a swapper in the system. >> > > You can move the iscsi_session->swapper field to the iscsi_cls_session > and have iscsi_swapdev take a iscsi_cls_session and set that flag. > iscsi_recv_pdu and iscsi_conn_error and all the llds can then access > this bit. > >> In order to preserve that information you need extra state, abusing this >> process flags is as good as propagating __GFP_EMERGENCY down the call >> chain with extra gfp_t arguments, perhaps even better, since it will >> make sure we catch all allocations. >>
Oh yeah, on the send side we also allocate some memory for the netlink interface if there is a connection error (iscsi_conn_failure -> iscsi_conn_error). And when that is called from the transmit side we can change the GFP_ATOMICs to GFP_NOIOs since we have process context. So I am just saying we need to set that flag in a couple more places (if you set it in iscsi_conn_error if iscsi_cls_session->swapper is set then don't worry about it), and that I need to change iscsi_conn_failure and iscsi_conn_error to take a gfp_t as an argument (or do a in_interrupt or something) so we can use GFP_NOIO in the transmit code. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
