Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 6 Feb 2001 16:57:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 6 Feb 2001 16:57:26 -0500 Received: from colorfullife.com ([216.156.138.34]:2057 "EHLO colorfullife.com") by vger.kernel.org with ESMTP id ; Tue, 6 Feb 2001 16:57:11 -0500 Message-ID: <3A80733E.A570B6C7@colorfullife.com> Date: Tue, 06 Feb 2001 22:57:18 +0100 From: Manfred Spraul X-Mailer: Mozilla 4.75 [en] (X11; U; Linux 2.2.16-22 i586) X-Accept-Language: en MIME-Version: 1.0 To: Linus Torvalds CC: Jens Axboe , Ben LaHaise , Ingo Molnar , "Stephen C. Tweedie" , Alan Cox , Steve Lord , Linux Kernel List , kiobuf-io-devel@lists.sourceforge.net, Ingo Molnar Subject: Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > On Tue, 6 Feb 2001, Manfred Spraul wrote: > > Jens Axboe wrote: > > > > > > > Several kernel functions need a "dontblock" parameter (or a callback, or > > > > a waitqueue address, or a tq_struct pointer). > > > > > > We don't even need that, non-blocking is implicitly applied with READA. > > > > > READA just returns - I doubt that the aio functions should poll until > > there are free entries in the request queue. > > The aio functions should NOT use READA/WRITEA. They should just use the > normal operations, waiting for requests. But then you end with lots of threads blocking in get_request() Quoting Ben's mail: <<<<<<<<< > > =) This is what I'm seeing: lots of processes waiting with wchan == > __get_request_wait. With async io and a database flushing lots of io > asynchronously spread out across the disk, the NR_REQUESTS limit is hit > very quickly. > >>>>>>>>> On an io bound server the request queue is always full - waiting for the next request might take longer than the actual io. -- Manfred - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/