Messages in this thread | | | Date | Mon, 28 Aug 2006 19:00:03 +0400 | From | Oleg Nesterov <> | Subject | Re: [PATCH -mm] select_bad_process: cleanup 'releasing' check |
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On 08/28, Nick Piggin wrote: > > On Sun, Aug 27, 2006 at 10:25:38PM +0400, Oleg Nesterov wrote: > > > > - releasing = test_tsk_thread_flag(p, TIF_MEMDIE) || > > - p->flags & PF_EXITING; > > - if (releasing) { > > - if (p->flags & PF_EXITING && p == current) { > > - chosen = p; > > - *ppoints = ULONG_MAX; > > - break; > > - } > > - return ERR_PTR(-1UL); > > - } > > + if ((p->flags & PF_EXITING) && p == current) { > > + chosen = p; > > + *ppoints = ULONG_MAX; > > + break; > > + } > > + if ((p->flags & PF_EXITING) || > > + test_tsk_thread_flag(p, TIF_MEMDIE)) > > + return ERR_PTR(-1UL); > > + > > Hmm, actually I think I spot a bug in the original logic: we don't want > to have more than 1 task with TIF_MEMDIE at once, becaues that gives it > access to memory reserves (but I saw it first in the new formulation, so > maybe that does suggest it is more readable ;) > > What I think should be done is the check for TIF_MEMDIE (and return -1) > first, and then the PF_EXITING test. At which point, if current is found to > be exiting, it should be chosen but not break... that way a subsequent MEMDIE > or EXITING task has the chance to trigger the -1 return.
Aha! The logic looked somewhat strange to me, but ...
> Anyway, if you don't want to do all that, I will when my hand gets better.
I have little understanding of this magic, i'd better not to try to fix it.
> Otherwise the 3 patches you sent look good, they could all have an > > Acked-by: Nick Piggin <npiggin@suse.de>
Thanks!
Oleg.
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