Messages in this thread | | | Date | Thu, 13 Jul 2006 18:18:35 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Convert idr's internal locking to _irqsave variant |
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On Thu, 13 Jul 2006 18:08:17 -0700 Roland Dreier <rdreier@cisco.com> wrote:
> > Good point, a try-again loop would work. Do we really need the caller to > > maintain a cache? I suspect something like > > > > drat: > > if (idr_pre_get(GFP_KERNEL) == ENOMEM) > > give_up(); > > spin_lock(); > > ret = idr_get_new(); > > spin_unlock(); > > if (ret == ENOMEM) > > goto drat; > > > > would do it. > > The problem (for my tiny brain at least) is that I don't know where > idr_pre_get() can put the memory it allocates if there's no lock in > the idr structure -- how do you maintain internal consistency if no > locks are held when filling the cache?
argh. Aren't you supposed to be on vacation or something?
> Having the caller hold a chunk of memory in a stack variable was the > trick I came up with to get around that.
Yes, that certainly works. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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