On Sun, Apr 22, 2012 at 9:59 AM, Sergei Trofimovich <sly...@gmail.com> wrote: > On Sat, 21 Apr 2012 22:54:41 +0200 > Ahmet Inan <ai...@mathematik.uni-freiburg.de> wrote: > >> On Fri, Apr 13, 2012 at 3:47 PM, Josef Bacik <jo...@redhat.com> wrote: >> > On Fri, Apr 13, 2012 at 02:26:19PM +0200, Ahmet Inan wrote: >> >> On Fri, Apr 13, 2012 at 1:22 PM, Ahmet Inan >> >> <ai...@mathematik.uni-freiburg.de> wrote: >> >> > On Fri, Apr 13, 2012 at 8:49 AM, cwillu <cwi...@cwillu.com> wrote: >> >> >>> dmesg and fstab attached as requested. >> >> >> >> >> >> Need dmesg after you've hit alt-sysrq-w a couple times during the slow >> >> >> period. >> >> > >> >> > here. >> >> > >> >> > i guess i should also increase dmesg history size next time. >> >> > other than the slow boot, everything seems normal after 10-20minutes. >> >> > >> >> > fyi: the space_cache option is not really helping with those >> >> > twenty computers. the one thing i observed is, that sometimes >> >> > they reboot fast and only to reboot slow again after that. >> >> >> >> sorry for spaming the list with my dmesg files, >> >> please tell me, how i could do better. >> >> >> >> here a more complete dmesg. >> > >> > Hrm so you are getting blocked task warnings just trying to mount the >> > filesystem, so either your disk is really really really slow or there's >> > something bigger going on. Let me think about this some and I'll get back >> > to >> > you. >> >> Josef, i finally found out something: >> >> btrfs in kernel => fast boot >> btrfs as module => very slow boot >> >> and here see the results: >> http://aam.mathematik.uni-freiburg.de/IAM/homepages/ainan/bootchart_btrfs_in_kernel.png >> >> this is much, much better! >> >> I dont understand why btrfs as a module performs that bad on rotating disk. >> On SSD i had no issues and also i never used space_cache before. > > There is a suspiction that putting space_cache (or anything else) to fstab > for rootfs > does not get applied due to a bug: > > http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg16039.html
Thats right. space_cache only got enabled for real, after ive set the option in the boot argument once. Even if it looks like it gets enabled in dmesg via /etc/fstab, the next boot without space_cache doesnt show space_cache enabled. But this is another problem i will look into later. At the moment the biggest problem is having btrfs as a module. > Do all of your affected computers run 3.4.0-rc kernels? They run vanilla/linux-3.3.2 with btrfs/for-linus. The unaffected computers have <= vanilla/linux-3.2.9 with btrfs/for-linus from 2 months ago or so. Ahmet -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
