Re: [RFC 00/29] De-stage android's sync framework
From: Gustavo Padovan
Date: Tue Jan 19 2016 - 12:52:41 EST
2016-01-19 John Harrison <John.C.Harrison@xxxxxxxxx>:
> On 19/01/2016 15:23, Gustavo Padovan wrote:
> >Hi Daniel,
> >2016-01-19 Daniel Vetter <daniel@xxxxxxxx>:
> >>On Fri, Jan 15, 2016 at 12:55:10PM -0200, Gustavo Padovan wrote:
> >>>From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> >>>This patch series de-stage the sync framework, and in order to accomplish that
> >>>a bunch of cleanups/improvements on the sync and fence were made.
> >>>The sync framework contained some abstractions around struct fence and those
> >>>were removed in the de-staging process among other changes:
> >>>Userspace visible changes
> >>> * The sw_sync file was moved from /dev/sw_sync to <debugfs>/sync/sw_sync. No
> >>> other change.
> >>>Kernel API changes
> >>> * struct sync_timeline is now struct fence_timeline
> >>> * sync_timeline_ops is now fence_timeline_ops and they now carry struct
> >>> fence as parameter instead of struct sync_pt
> >>> * a .cleanup() fence op was added to allow sync_fence to run a cleanup when
> >>> the fence_timeline is destroyed
> >>> * added fence_add_used_data() to pass a private point to struct fence. This
> >>> pointer is sent back on the .cleanup op.
> >>> * The sync timeline function were moved to be fence_timeline functions:
> >>> - sync_timeline_create() -> fence_timeline_create()
> >>> - sync_timeline_get() -> fence_timeline_get()
> >>> - sync_timeline_put() -> fence_timeline_put()
> >>> - sync_timeline_destroy() -> fence_timeline_destroy()
> >>> - sync_timeline_signal() -> fence_timeline_signal()
> >>> * sync_pt_create() was replaced be fence_create_on_timeline()
> >>>Internal changes
> >>> * fence_timeline_ops was removed in favor of direct use fence_ops
> >>> * fence default functions were created for fence_ops
> >>> * removed structs sync_pt, sw_sync_timeline and sw_sync_pt
> >>Bunch of fairly random comments all over:
> >>- include/uapi/linux/sw_sync.h imo should be dropped, it's just a private
> >> debugfs interface between fence fds and the testsuite. Since the plan is
> >> to have the testcases integrated into the kernel tree too we don't need
> >> a public header.
> >>- similar for include/linux/sw_sync.h Imo that should all be moved into
> >> sync_debug.c. Same for sw_sync.c, that should all land in sync_debug
> >> imo, and made optional with a Kconfig option. At least we should reuse
> >> CONFIG_DEBUGFS.
> >These two items sounds reasonable to me.
> I have just posted our in-progress IGT for testing i915 syncs (with a CC of
> Gustavo). It uses the sw_sync mechanisms. Can you take a quick look and see
> if it is the kind of thing you would expect us to be doing? Or is it using
> interfaces that you are planning to remove and/or make kernel only?
> I'm not sure having a kernel only test is the best way to go. Having user
> land tests like IGT would be much more versatile.
I agree with you, we should allow IGT and other test tools to access
sw_sync. include/linux/sw_sync.h can be kept private, but the uapi one
needs wil be needed for testing, unless we replicate the header file
inside IGT, but not sure if it is a good idea.