> On Nov 13, 2015, at 16:41, Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> wrote: > >> >> Instead of the condition, we could have: >> >> __entry->pfn = page ? page_to_pfn(page) : -1; >> >> >> But if there's no reason to do the tracepoint if page is NULL, then >> this patch is fine. I'm just throwing out this idea. >> > we trace only if page is valid > > --- linux-next/mm/huge_memory.c Fri Nov 13 16:00:22 2015 > +++ b/mm/huge_memory.c Fri Nov 13 16:26:19 2015 > @@ -1987,7 +1987,8 @@ static int __collapse_huge_page_isolate( > > out: > release_pte_pages(pte, _pte); > - trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, > + if (page) > + trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, > referenced, writable, result); > return 0; > } > — > my V4 patch move if (!page) into trace function, so that we don’t need call page_to_fn() if the trace if disabled . more efficient . Thanks -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href