Messages in this thread |  | | Date | Mon, 30 Dec 2013 17:58:47 +0000 | From | Zoltan Kiss <> | Subject | Re: [Xen-devel] [PATCH net-next v2 2/9] xen-netback: Change TX path from grant copy to mapping |
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On 17/12/13 21:49, Konrad Rzeszutek Wilk wrote: > On Thu, Dec 12, 2013 at 11:48:10PM +0000, Zoltan Kiss wrote: >> @@ -485,6 +520,22 @@ void xenvif_disconnect(struct xenvif *vif) >> >> void xenvif_free(struct xenvif *vif) >> { >> + int i, unmap_timeout = 0; >> + >> + for (i = 0; i < MAX_PENDING_REQS; ++i) { >> + if (vif->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) { >> + i = 0; >> + unmap_timeout++; >> + msleep(1000); > > You don't want to use schedule() and a wakeup here to allow other threads > to do their work? Yep, schedule_timeout() would be nicer indeed
> >> + if (unmap_timeout > 9 && >> + net_ratelimit()) >> + netdev_err(vif->dev, >> + "Page still granted! Index: %x\n", i); >> + } >> + } >> + >> + free_xenballooned_pages(MAX_PENDING_REQS, vif->mmap_pages); > > How about just stashing those pages on a 'I can't free them' list that will > keep them forever. And if that list gets truly large then switch back to > grant_copy? But then what would you answer to the guest? You can't shoot the shared ring until there is an outstanding slot. On the other hand, doing a copy would just move the memory leak into the backend, which could be problematic if a guest figures out how to make a packet which can get stucked somewhere in the backend.
Zoli
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