vm: retire pa_lock
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Authored by alc on Mon, Jun 9, 9:16 PM.

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markj
kib

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rG797020a76406: vm: retire vm_page_lock()

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alc created this revision.Mon, Jun 9, 9:16 PM

Herald added subscribers: linuxkpi, emaste. · View Herald TranscriptMon, Jun 9, 9:16 PM

alc requested review of this revision.Mon, Jun 9, 9:16 PM

alc added inline comments.Mon, Jun 9, 9:19 PM

sys/compat/linuxkpi/common/include/linux/highmem.h
82–83	This seems highly suspect, and warrants investigation.

markj added inline comments.Mon, Jun 9, 9:19 PM

sys/compat/linuxkpi/common/include/linux/highmem.h
84	This is a hack that I don't understand, but the change is probably ok.
sys/compat/linuxkpi/common/include/linux/mm.h
417	These are used by drm-kmod. I believe changing them to vm_page_tryxbusy() and vm_page_xunbusy() would be correct. I can test such a change.

alc added inline comments.Mon, Jun 9, 9:22 PM

sys/compat/linuxkpi/common/include/linux/mm.h
406–418	Is the out-of-tree i915kms driver that you mentioned using these?

markj added inline comments.Mon, Jun 9, 9:29 PM

sys/compat/linuxkpi/common/include/linux/mm.h
406–418	Yes, here: https://github.com/freebsd/drm-kmod/blob/master/drivers/gpu/drm/i915/gem/i915_gem_userptr.c#L209 It's more correct to use the busy lock there. I'm not convinced that that code is sane at all in any case, but now I'm not sure that the userptr code gets compiled in at all. All of this file is conditionally defined based on whether CONFIG_MMU_NOTIFIER is configured, and I can't see any evidence that it is.

Use busy style synchronization in linux emulation.

Delete more unused declarations from vm_page.h.

markj accepted this revision.Tue, Jun 10, 2:18 PM

markj added inline comments.

sys/compat/linuxkpi/common/include/linux/mm.h
406–418	That code isn't compiled indeed, so we could drop these wrappers as well.

This revision is now accepted and ready to land.Tue, Jun 10, 2:18 PM

Can we remove PA_LOCK_COUNT too? There is one use in a powerpc64 pmap to size the PV lock array, but substituting MAXCPU there would be more consistent with other platforms and would also avoid changing the size of the array.

Retire PA_LOCK_COUNT.

This revision now requires review to proceed.Tue, Jun 10, 5:44 PM

Herald added a subscriber: jhibbits. · View Herald TranscriptTue, Jun 10, 5:44 PM

markj accepted this revision.Tue, Jun 10, 6:08 PM

This revision is now accepted and ready to land.Tue, Jun 10, 6:08 PM

alc added a reviewer: kib.Tue, Jun 10, 7:17 PM

kib accepted this revision.Wed, Jun 11, 3:06 AM

Closed by commit rG797020a76406: vm: retire vm_page_lock() (authored by alc). · Explain WhyWed, Jun 11, 8:22 PM

This revision was automatically updated to reflect the committed changes.

alc added a commit: rG797020a76406: vm: retire vm_page_lock().

Herald added a subscriber: imp. · View Herald TranscriptWed, Jun 11, 8:22 PM