On Thu, 2006-09-14 at 16:03 -0500, Mike Christie wrote: > 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).
D'0h again, I'd forgotten I'd used it there too. hit refresh :-) - 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
