From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WMXyo-0006hc-Lm for user-mode-linux-devel@lists.sourceforge.net; Sun, 09 Mar 2014 07:17:02 +0000 Received: from ivanoab3.miniserver.com ([89.200.143.206]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1WMXyn-00079m-5b for user-mode-linux-devel@lists.sourceforge.net; Sun, 09 Mar 2014 07:17:02 +0000 Message-ID: <531C1559.2080404@kot-begemot.co.uk> Date: Sun, 09 Mar 2014 07:16:41 +0000 From: Anton Ivanov MIME-Version: 1.0 References: <1394217468-734972-1-git-send-email-anton.ivanov@kot-begemot.co.uk> <1394217468-734972-3-git-send-email-anton.ivanov@kot-begemot.co.uk> <531BA8D0.2050307@nod.at> In-Reply-To: <531BA8D0.2050307@nod.at> List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: Re: [uml-devel] [PATCH 3/3] BUG: Inapprorpiate choice of IPC To: Richard Weinberger Cc: user-mode-linux-devel@lists.sourceforge.net Yes, that is why I resent it. My mistake when moving the commits from the main tree to a branch which was just for submission. The file.c frag is from patch-2 (the memory corruption one). Please use the resent version, it has them in the right places. Alternatively, I can resend them again off-list. A. On 08/03/14 23:33, Richard Weinberger wrote: > > Am 07.03.2014 19:37, schrieb anton.ivanov@kot-begemot.co.uk: >> From: Anton Ivanov >> >> PIPE is the wrong IPC for this type of inter-thread communication. >> >> For more details see: >> >> http://stackoverflow.com/questions/4624071/pipe-buffer-size-is-4k-or-64k >> >> The observations on that thread have been confirmed by us for UML's >> UBD driver. If you load UML with network IO and do disk IO at the same >> time the UBD IO helper thread fails to process requests fast enough. >> >> In most cases this will lead to a slowdown in disk IO as well as >> inability to execute new processes until the network load goes away. >> In some cases however it will not recover. Example - with our new high >> performance 1G+ network drivers a wget of 1G file from the network >> is a nearly guaranteed crash if it writes out to UBD. >> >> The crashes and the slowdowns are not observed with this patch - >> it switches the IPC to socket which does not have the pipe granularity >> and queue size problems. >> >> This signifies a problem with overall UBD error handling which this >> patch fails to fix. The workaround should be good enough for most >> cases. >> >> Signed-off-by: Anton Ivanov >> --- >> arch/um/drivers/ubd_kern.c | 2 +- >> arch/um/drivers/ubd_user.c | 2 +- >> arch/um/os-Linux/file.c | 2 +- >> 3 files changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c >> index 944453a..c9a5717 100644 >> --- a/arch/um/drivers/ubd_kern.c >> +++ b/arch/um/drivers/ubd_kern.c >> @@ -1291,7 +1291,7 @@ static void do_ubd_request(struct request_queue *q) >> n = os_write_file(thread_fd, &io_req, >> sizeof(struct io_thread_req *)); >> if(n != sizeof(struct io_thread_req *)){ >> - if(n != -EAGAIN) >> + if(!((n == -EAGAIN) || (n == -ENOBUFS))) >> printk("write to io thread failed, " >> "errno = %d\n", -n); >> else if(list_empty(&dev->restart)) >> diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c >> index 007b94d..f1f84a4 100644 >> --- a/arch/um/drivers/ubd_user.c >> +++ b/arch/um/drivers/ubd_user.c >> @@ -32,7 +32,7 @@ int start_io_thread(unsigned long sp, int *fd_out) >> { >> int pid, fds[2], err; >> >> - err = os_pipe(fds, 1, 1); >> + err = socketpair(AF_UNIX, SOCK_STREAM, 0, (int *) &fds); >> if(err < 0){ >> printk("start_io_thread - os_pipe failed, err = %d\n", -err); >> goto out; >> diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c >> index c879b12..a4f0e65 100644 >> --- a/arch/um/os-Linux/file.c >> +++ b/arch/um/os-Linux/file.c >> @@ -240,7 +240,7 @@ void os_close_file(int fd) >> int os_fsync_file(int fd) >> { >> if (fsync(fd) < 0) >> - return -errno >> + return -errno; > Huh? > I think this does not belong to the patch. > > The other drivers look good. Thanks a lot for pushing this work upstream! > We are already at -rc5. I'll send the patches to Linus within the next merge window > and mark them for stable. > > Thanks, > //richard > -- "If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Paul Neal "Red" Adair A. R. Ivanov E-mail: anton.ivanov@kot-begemot.co.uk ------------------------------------------------------------------------------ Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce. With Perforce, you get hassle-free workflows. Merge that actually works. Faster operations. Version large binaries. Built-in WAN optimization and the freedom to use Git, Perforce or both. Make the move to Perforce. http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel