In the dmesg of rc4, I can see svn hang in shrink_dellalloc and there's two flush-btrfs threads hang there too.
Josef, it seems you are the expert in this area. Could you take a quick look? Thanks! -----Original Message----- From: Johannes Hirte [mailto:johannes.hi...@fem.tu-ilmenau.de] Sent: Wednesday, February 23, 2011 6:27 AM To: Zhong, Xin Cc: Maria Wikström; linux-btrfs@vger.kernel.org Subject: Re: [PATCH v2]Btrfs: pwrite blocked when writing from the mmaped buffer of the same page On Friday 11 February 2011 05:39:39 Zhong, Xin wrote: > Hi, > > Could you paste the output of sysrq+t here? Thanks! Sorry for the long delay. I've attached the dmesg output of sysrq-t from 2.6.38-rc3 and rc4 as the behavior differs between both versions. With rc3 it don't need any interaction. I start 'emerge sys-devel/libgcrypt', the tasks hangs and top shows a svn process eating 100% CPU. With rc4 the system hangs too but the CPU load stays low. When I try to cancel the emerge process (ctrl c) the CPU load goes up and top shows the svn process together with a flush- btrfs task, eating the CPU.
