Messages in this thread | | | Date | Thu, 23 Jan 2014 21:48:29 -0800 | From | Matt Wilson <> | Subject | Re: [PATCH v6] xen/grant-table: Avoid m2p_override during mapping |
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On Thu, Jan 23, 2014 at 09:23:44PM +0000, Zoltan Kiss wrote: > The grant mapping API does m2p_override unnecessarily: only gntdev needs it, > for blkback and future netback patches it just cause a lock contention, as > those pages never go to userspace. Therefore this series does the following: > - the original functions were renamed to __gnttab_[un]map_refs, with a new > parameter m2p_override > - based on m2p_override either they follow the original behaviour, or just set > the private flag and call set_phys_to_machine > - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with > m2p_override false > - a new function gnttab_[un]map_refs_userspace provides the old behaviour > > It also removes a stray space from page.h and change ret to 0 if > XENFEAT_auto_translated_physmap, as that is the only possible return value > there. > > v2: > - move the storing of the old mfn in page->index to gnttab_map_refs > - move the function header update to a separate patch > > v3: > - a new approach to retain old behaviour where it needed > - squash the patches into one > > v4: > - move out the common bits from m2p* functions, and pass pfn/mfn as parameter > - clear page->private before doing anything with the page, so m2p_find_override > won't race with this > > v5: > - change return value handling in __gnttab_[un]map_refs > - remove a stray space in page.h > - add detail why ret = 0 now at some places > > v6: > - don't pass pfn to m2p* functions, just get it locally > > Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> > Suggested-by: David Vrabel <david.vrabel@citrix.com>
Apologies for coming in late on this thread. I'm quite behind on xen-devel mail that isn't CC: to me.
It seems to have been forgotten that Anthony and I proposed a similar change last November.
https://lkml.kernel.org/r/1384307336-5328-1-git-send-email-anthony@codemonkey.ws
Or am I misunderstanding the change?
--msw
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