On Thu, 2007-02-22 at 10:16 +0100, Peter Zijlstra wrote:

On Wed, 2007-02-21 at 16:53 +0100, Arjan van de Ven wrote:

quoted

quoted

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..

would something like this:

#define PF_PUSH(tsk, pflags, mask)		\
do {						\
	(pflags) = ((tsk)->flags) & (mask);	\
} while (0)


#define PF_POP(tsk, pflags, mask)		\
do {						\
	((tsk)->flags &= ~(mask);		\
	((tsk)->flags |= (pflags);		\
} while (0)

be useful, or shall I just open code it in various places?

technically all you need is __get_bit and __set_bit() right?
(well a set_bit which sets to a value, not to always-1)

more generic name at least ;)

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
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