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 think we would want to set this flag at a lower level. Something closer to where the skbuf is allocated? - 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
