Messages in this thread | | | Date | Fri, 12 Jun 2009 12:07:56 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v2] slab,slub: ignore __GFP_WAIT if we're booting or suspending |
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* Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> On Fri, Jun 12, 2009 at 12:10 PM, Ingo Molnar<mingo@elte.hu> wrote: > >> @@ -1548,6 +1548,20 @@ new_slab: > >> goto load_freelist; > >> } > >> > >> + /* > >> + * Lets not wait if we're booting up or suspending even if the user > >> + * asks for it. > >> + */ > >> + if (system_state != SYSTEM_RUNNING) > >> + gfpflags &= ~__GFP_WAIT; > > > > Hiding that bug like that is not particularly clean IMO. We should > > not let system_state hacks spread like that. > > > > We emit a debug warning but dont crash, so all should be fine and > > the culprits can then be fixed, right? > > OK, lets not use system_state then and go with Ben's approach > then. Again, neither of the patches are about "hiding buggy > callers" but changing allocation policy wrt. gfp flags during boot > (and later on during suspend).
IMHO such invisible side-channels modifying the semantics of GFP flags is a bit dubious.
We could do GFP_INIT or GFP_BOOT. These can imply other useful modifiers as well: panic-on-failure for example. (this would clean up a fair amount of init code that currently checks for an panics on allocation failure.)
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