Re: [PATCH 03/29] mm: allow PF_MEMALLOC from softirq context

From: Arjan van de Ven
Date: Wed Feb 21 2007 - 10:54:34 EST



> Index: linux-2.6-git/kernel/softirq.c
> ===================================================================
> --- linux-2.6-git.orig/kernel/softirq.c 2006-12-14 10:02:18.000000000 +0100
> +++ linux-2.6-git/kernel/softirq.c 2006-12-14 10:02:52.000000000 +0100
> @@ -209,6 +209,8 @@ asmlinkage void __do_softirq(void)
> __u32 pending;
> int max_restart = MAX_SOFTIRQ_RESTART;
> int cpu;
> + unsigned long pflags = current->flags;
> + current->flags &= ~PF_MEMALLOC;
>
> pending = local_softirq_pending();
> account_system_vtime(current);
> @@ -247,6 +249,7 @@ restart:
>
> account_system_vtime(current);
> _local_bh_enable();
> + current->flags = pflags;

this wipes out all the flags in one go.... evil.
What if something just selected this process for OOM killing? you nuke
that flag here again. Would be nicer if only the PF_MEMALLOC bit got
inherited in the restore path..




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