On Thursday 30 October 2014 02:02 PM, Rock Lee wrote:
Hi, everyone
I am implementing a simple driver to experiment with wait queue.Two or more read processes block until a write process changes a flag and call wake_up_interruptible().I expect that a write process will only wake up one read process.However, once a write process calls wake_up_interruptible() , all the read processes are awaken. How can I wake up one process from the wait queue?
You can use exclusive wait queues, which wakes up only one process from the queue. Although the general idea that is followed is: all the process are woken up once the resource is made available. And then the access to that resource is guarded by a lock, which in turn allows only one process to access the resource. Rest of the processes are pushed backed to sleep(or busy wait). ------------------------------------------------------------------------------------------------------------------------------- [ C-DAC is on facebook. Kindly follow us on the following url: https://www.facebook.com/CDACINDIA ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. ------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------- [ C-DAC is on Social-Media too. Kindly follow us at: Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. -------------------------------------------------------------------------------------------------------------------------------