On Wed, Jul 3, 2024 at 4:40 AM Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > Sorry for the late reply. I'll try to read this version/discussion > when I have time... yes, I have already promised this before, sorry :/ > > On 07/01, Andrii Nakryiko wrote: > > > > There is no task_struct passed into get_user_pages_remote() anymore, > > drop the parts of comment mentioning NULL tsk, it's just confusing at > > this point. > > Agreed. > > > @@ -2030,10 +2030,8 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr) > > goto out; > > > > /* > > - * The NULL 'tsk' here ensures that any faults that occur here > > - * will not be accounted to the task. 'mm' *is* current->mm, > > - * but we treat this as a 'remote' access since it is > > - * essentially a kernel access to the memory. > > + * 'mm' *is* current->mm, but we treat this as a 'remote' access since > > + * it is essentially a kernel access to the memory. > > */ > > result = get_user_pages_remote(mm, vaddr, 1, FOLL_FORCE, &page, NULL); > > OK, this makes it less confusing, so > > Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx> > > > --------------------------------------------------------------------- > but it still looks confusing to me. This code used to pass tsk = NULL > only to avoid tsk->maj/min_flt++ in faultin_page(). > > But today mm_account_fault() increments these counters without checking > FAULT_FLAG_REMOTE, mm == current->mm, so it seems it would be better to > just use get_user_pages() and remove this comment? I don't know, it was a drive-by cleanup which I'm starting to regret already :) > > Oleg. >
