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As vhost scsi device struct is large, if the device is created on a busy system, kzalloc() might fail, so this patch does a fallback to vzalloc(). As vmalloc() adds overhead on data-path, add __GFP_REPEAT to kzalloc() flags to do this fallback only when really needed. Reported-by: Dan Aloni <alonid at stratoscale.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- I put this on my vhost fixes branch, intend to merge for 3.12. Dan, could you please confirm this works for you? drivers/vhost/scsi.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertio...

As vhost scsi device struct is large, if the device is created on a busy system, kzalloc() might fail, so this patch does a fallback to vzalloc(). As vmalloc() adds overhead on data-path, add __GFP_REPEAT to kzalloc() flags to do this fallback only when really needed. Reported-by: Dan Aloni <alonid at stratoscale.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- I put this on my vhost fixes branch, intend to merge for 3.12. Dan, could you please confirm this works for you? drivers/vhost/scsi.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertio...

...ocation failed once on my development machine. > > > > Saw it would be prudent to split the bulk of it, which is the vqs array > > into separately allocated parts. sizeof(struct vhost_virtqueue) is > > currently 16816 bytes. > > > > Signed-off-by: Dan Aloni <alonid at stratoscale.com> > > This extra indirection is likely to have measureable cost though. > > net core saw a similar problem, it was fixed in patch > net: allow large number of tx queues > > So let's do it in a similar way: try to allocate with > GFP_KERNEL | _...

...ocation failed once on my development machine. > > > > Saw it would be prudent to split the bulk of it, which is the vqs array > > into separately allocated parts. sizeof(struct vhost_virtqueue) is > > currently 16816 bytes. > > > > Signed-off-by: Dan Aloni <alonid at stratoscale.com> > > This extra indirection is likely to have measureable cost though. > > net core saw a similar problem, it was fixed in patch > net: allow large number of tx queues > > So let's do it in a similar way: try to allocate with > GFP_KERNEL | _...

...ruct is large, if the device is > created on a busy system, kzalloc() might fail, so this patch does a > fallback to vzalloc(). > As vmalloc() adds overhead on data-path, add __GFP_REPEAT > to kzalloc() flags to do this fallback only when really needed. > Reported-by: Dan Aloni <alonid at stratoscale.com> > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > I put this on my vhost fixes branch, intend to merge for 3.12. > Dan, could you please confirm this works for you? > drivers/vhost/scsi.c | 41 +++++++++++++++++++++++++++-------------- &g...