Mike Christie wrote: > Peter Zijlstra wrote: >> On Thu, 2006-09-14 at 14:22 -0500, Mike Christie wrote: >>> Peter Zijlstra wrote: >>>> On Wed, 2006-09-13 at 15:50 -0500, Mike Christie wrote: >>>>> Peter Zijlstra wrote: >>>>>> Implement sht->swapdev() for iSCSI. This method takes care of reserving >>>>>> the extra memory needed and marking all relevant sockets with SOCK_VMIO. >>>>>> >>>>>> When used for swapping, TCP socket creation is done under GFP_MEMALLOC >>>>>> and >>>>>> the TCP connect is done with SOCK_VMIO to ensure their success. Also the >>>>>> netlink userspace interface is marked SOCK_VMIO, this will ensure that >>>>>> even >>>>>> under pressure we can still communicate with the daemon (which runs as >>>>>> mlockall() and needs no additional memory to operate). >>>>>> >>>>>> Netlink requests are handled under the new PF_MEM_NOWAIT when a swapper >>>>>> is >>>>>> present. This ensures that the netlink socket will not block. User-space >>>>>> will >>>>>> need to retry failed requests. >>>>>> >>>>>> The TCP receive path is handled under PF_MEMALLOC for SOCK_VMIO sockets. >>>>>> This makes sure we do not block the critical socket, and that we do not >>>>>> fail to process incomming data. >>>>>> >>>>>> Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]> >>>>>> CC: Mike Christie <[EMAIL PROTECTED]> >>>>>> --- >>>>>> drivers/scsi/iscsi_tcp.c | 103 >>>>>> +++++++++++++++++++++++++++++++----- >>>>>> drivers/scsi/scsi_transport_iscsi.c | 23 +++++++- >>>>>> include/scsi/libiscsi.h | 1 >>>>>> include/scsi/scsi_transport_iscsi.h | 2 >>>>>> 4 files changed, 113 insertions(+), 16 deletions(-) >>>>>> >>>>>> Index: linux-2.6/drivers/scsi/iscsi_tcp.c >>>>>> =================================================================== >>>>>> --- linux-2.6.orig/drivers/scsi/iscsi_tcp.c >>>>>> +++ linux-2.6/drivers/scsi/iscsi_tcp.c >>>>>> @@ -42,6 +42,7 @@ >>>>>> #include <scsi/scsi_host.h> >>>>>> #include <scsi/scsi.h> >>>>>> #include <scsi/scsi_transport_iscsi.h> >>>>>> +#include <scsi/scsi_device.h> >>>>>> >>>>>> #include "iscsi_tcp.h" >>>>>> >>>>>> @@ -845,9 +846,13 @@ iscsi_tcp_data_recv(read_descriptor_t *r >>>>>> int rc; >>>>>> struct iscsi_conn *conn = rd_desc->arg.data; >>>>>> struct iscsi_tcp_conn *tcp_conn = conn->dd_data; >>>>>> - int processed; >>>>>> + int processed = 0; >>>>>> char pad[ISCSI_PAD_LEN]; >>>>>> struct scatterlist sg; >>>>>> + unsigned long pflags = current->flags; >>>>>> + >>>>>> + if (sk_has_vmio(tcp_conn->sock->sk)) >>>>>> + current->flags |= PF_MEMALLOC; >>>>>> >>>>> Is this too late or not needed or what is it for? This function gets run >>>>> from the network layer's softirq and at this point we have a skbuff with >>>>> data that we want to process. The iscsi layer also does not allocate >>>>> memory for read or write IO in this path. >>>> 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 >> > > You are drowning me in patches :) I did not see that one. I was still > commenting on this patch :) > > The new patch looks ok. >
Oh, I think you need a sock_put to go with netlink lookup (lookup does a hold). - 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
