On 06/05/2019 04:53 PM, Matthew Wilcox wrote: > On Wed, Jun 05, 2019 at 09:19:22PM +1000, Michael Ellerman wrote: >> Anshuman Khandual <anshuman.khandual@xxxxxxx> writes: >>> Similar notify_page_fault() definitions are being used by architectures >>> duplicating much of the same code. This attempts to unify them into a >>> single implementation, generalize it and then move it to a common place. >>> kprobes_built_in() can detect CONFIG_KPROBES, hence notify_page_fault() >>> need not be wrapped again within CONFIG_KPROBES. Trap number argument can >>> now contain upto an 'unsigned int' accommodating all possible platforms. >> ... >> >> You've changed several of the architectures from something like above, >> where it disables preemption around the call into the below: >> >> >> Which skips everything if we're preemptible. Is that an equivalent >> change? If so can you please explain why in more detail. > > See the discussion in v1 of this patch, which you were cc'd on. > > I agree the description here completely fails to mention why the change. > It should mention commit a980c0ef9f6d8c. I will update the commit message to include an explanation for this new preempt behavior in the generic definition.