Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes: > On Mon, Jun 15, 2020 at 3:16 PM Peter Xu <peterx@xxxxxxxxxx> wrote: >> This series tries to address all of them by introducing mm_fault_accounting() >> first, so that we move all the page fault accounting into the common code base, >> then call it properly from arch pf handlers just like handle_mm_fault(). > > Hmm. > > So having looked at this a bit more, I'd actually like to go even > further, and just get rid of the per-architecture code _entirely_. <snip> > One detail worth noting: I do wonder if we should put the > > perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); > > just in the arch code at the top of the fault handling, and consider > it entirely unrelated to the major/minor fault handling. The > major/minor faults fundamnetally are about successes. But the plain > PERF_COUNT_SW_PAGE_FAULTS could be about things that fail, including > things that never even get to this point at all. Yeah I think we should keep it in the arch code at roughly the top. If it's moved to the end you could have a process spinning taking bad page faults (and fixing them up), and see no sign of it from the perf page fault counters. cheers
