On 12/27/06, hemen.kapadia@xxxxxxx <hemen.kapadia@xxxxxxx> wrote: >> Will the up() method of the semaphore execute a waiting process in the >> semaphore queue each time it is executed (assuming that there are waiting >> processes in the queue) or only when the new value of the semaphore is >> greater than or equal to 0 ? >>think about how semaphores are designed ... every up() should wake up a process Precisely, as I thought it shoudl work. However i got confused when I read the following in "Understanding the Linux Kernel Book" "The up( ) method increments the value of the semaphore and, ***if its new value is greater than or equal to 0***, reactivates one or more processes in the semaphore list." That If seems to indicate that the job is picked from the queve only if the condition is TRUE, which is immaterial in reality. Thanks Mike. if you look at the implementation you see: up() calls __up_wakeup() __up_wakeup() calls __up() __up() calls wake_up() -mike =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
