-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 09/03/2014 12:08 PM, Oleg Nesterov wrote: > On 09/02, Oleg Nesterov wrote: >> >> The usage of TASK_DEAD in task_numa_fault() is wrong in any >> case. > > Rik, I can't understand why task_numa_fault() needs this check at > all, but "if (p->state == TASK_DEAD)" looks certainly wrong. You > could replace this check with BUG_ON(p->state == TASK_DEAD). > Perhaps you meant PF_EXITING?
I do not know why that code is in there, either. I suspect it was added after some conversation on irc, with either Peter or Mel. > And a stupid (really, I don't understand this code) question: > > /* for example, ksmd faulting in a user's mm */ if (!p->mm) > return; > > OK, but perhaps it make sense to pass "mm" as another argument and > do > > /* ksmd faulting in a user's mm, or debugger, or kthread use_mm() > caller */ if (p->mm != mm) return; I suppose that makes sense, since it would be possible for one task to cause a page fault in another task's mm, with eg. ptrace peek/poke or similar code paths. Currently the numa code could end up accounting such a fault in the wrong mm, when it would be better to not account the fault at all. This is a bit of a corner case, and probably not the highest priority thing to fix right now, but it would be fairly easy. - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUB0LQAAoJEM553pKExN6DGBEIALBBKq0N3GlzjRWBzxI361dg +Xn/C789TZFhk2tvZMNYwJgZRS7xaTRr6IfNcMZNlT9enVlXtrPj2BFiTJ1dF+bh iwr2eS8c+VVHM+lvzEyiNbrTnvgVNgECI76qsjpvuS0BiUKLh51JSTNLdHA4/CEZ yJrd+WyulTrv9dHchIO53MQ8+ttCNdzQv/1JK+L2R7vizGnnwA6FysTVQFOPLDxd ZdvdlAb16uouYQ+1skufxwftvydkbv5voDzp2kb7W0vtwp45MEmj72KPCjHvm1JV XoX6x1tdNuuZtGdY6WQvFup9ABUnMnILHaX4bkYvxxUqE6/NbfNGOC0CBO41IjE= =NFQx -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/