I am having a PCIe device , it asserts two types if Tx interrupts i.e. TX Queue count interrupt & TX Queue timer interrupt.
TX Queue count interrupt related to “TX Queue count register” : No. of TXQ transactions to move from host before asserting TX Queue count interrupt TX Queue timer interrupt related to “TX Queue timer register”: Time out value in uSec. The timeout covers the case where a burst of transactions are sent but not enough to trigger the count interrupt. I am getting lot many TX Queue timer interrupts for larger write requests and the current driver implementation is calling complete() API in both TX Queue count & timer interrupts. Here “x->done > 0” because of multiple TX Queue timer interrupts. Yes I agree with you. I need to correct driver write() function. Thanks, Naveen On Fri, Mar 6, 2015 at 2:18 PM, Michal Hocko <mho...@suse.cz> wrote: > On Fri 06-03-15 14:04:53, Naveen Kumar Parna wrote: >> Thanks Michal. >> >> Now I am clearing x->done to zero before >> wait_for_completion_interruptible_timeout. > > You shouldn't touch this internal thing. Why would you want that > anyway? If x->done > 0 then there has been something completed. > >> On Thu, Mar 5, 2015 at 6:53 PM, Michal Hocko <mho...@suse.cz> wrote: >> > On Wed 04-03-15 18:46:43, Naveen Kumar Parna wrote: >> >> Hello, >> >> >> >> I have a question regarding the synchronization mechanism between >> >> wait_for_completion_interruptible_timeout() & complete(). I used >> >> complete() API in the ISR Tx interrupt path and >> >> wait_for_completion_interruptible_timeout() in struct file_operations >> >> .write method. >> >> >> >> Let assume a scenario in which Tx interrupt occurred and ISR called >> >> complete() API before any process actually blocked at write method on >> >> wait_for_completion_interruptible_timeout(). >> >> >> >> After a few milli seconds, a process called write() API. Does it gets >> >> blocked on wait_for_completion_interruptible_timeout() for completion >> >> of a specific task to be signaled from new Tx interrupt? >> > >> > No, see do_wait_for_common resp. complete and x->done handling. >> > >> > -- >> > Michal Hocko >> > SUSE Labs > > -- > Michal Hocko > SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
