Thank you sirs. But in fact, I don't alloc/free for every packet. I did exactly as what you said---reuse. I am a little confused why GFP_ATOMIC can work but GFP_KERNEL will cause the system to panic. Does it because that GFP_KERNEL can sleep in kmalloc, then ip_xmit_queue will be held or something? But anyway, GFP_ATOMIC works perfectly. On Thu, Jan 2, 2014 at 1:15 AM, Mulyadi Santosa <mulyadi.santosa@gmail.com>wrote:
On Thu, Jan 2, 2014 at 12:41 PM, <Valdis.Kletnieks@vt.edu> wrote:
On Thu, 02 Jan 2014 12:12:49 +0700, Mulyadi Santosa said:
Other than what others have said, IMHO it is better to avoid such rapid alloc/free, assuming your code fragment is running on every packet reception/sending.
Instead, I suggest to allocate the memory before the ip_queue_xmit and use-reuse it inside ip_queue_xmit.
Be careful with re-entrancy issues - you'll want a separate instance of memory for all possible concurrent callers of ip_queue_xmit (you may need one per active interface, because you can e transmitting packets on multiple interfaces at the same time).
Ah yes, you're correct Valdis. Thanks for note.
-- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com