Messages in this thread | | | Date | Tue, 29 Sep 2009 16:55:24 +0530 | Subject | GFP_NOWAIT and GFP_NOMEMALLOC | From | "Leonidas ." <> |
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Hi list,
I am new here, I have googled/binged enough before posting this message, in case of redundancy please point me to appropriate links/resources etc.
I want to kmalloc memory while holding spinlocks in process context, here I can't use GFP_KERNEL flag since it can sleep. Using GFP_ATOMIC guarantees that allocation will succeed by allocating from emergency pools if needed. But I dont think, I need to use emergency pool and I want to limit my memory consumption to ZONE_NORMAL without sleeping, my module is ready to handle the allocation failure if any.
Something like,
ptr = kmalloc(..., GFP_KERNEL | GFP_DONT_SLEEP );
if( !ptr ) {
/*GFP_KERNEL failed, Use GFP_ATOMIC pool*/ ptr = kmalloc(..., GFP_ATOMIC );
} /*Go ahead and do stuff*/
Is there any flag which fetches memory from GFP_KERNEL pool with a guarantee that it will not sleep?
Does GFP_NOWAIT | GFP_KERNEL guarantee that?
Is ( GFP_NOWAIT | GFP_KERNEL ) == ( GFP_ATOMIC - dont access emergency pools)?
I am a bit confused about GFP_NOWAIT and GFP_NOMEMALLOC, any pointers will be helpful.
-Leo.
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