Messages in this thread | | | Date | Mon, 16 Apr 2012 21:07:07 +0800 | From | Fengguang Wu <> | Subject | Re: [Lsf] [RFC] writeback and cgroup |
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On Mon, Apr 16, 2012 at 08:54:32AM -0400, Vivek Goyal wrote: > On Sat, Apr 14, 2012 at 02:25:14PM +0200, Peter Zijlstra wrote: > > On Wed, 2012-04-11 at 11:40 -0400, Vivek Goyal wrote: > > > > > > Ok, that's good to know. How would we configure this special bdi? I am > > > assuming there is no backing device visible in /sys/block/<device>/queue/? > > > Same is true for network file systems. > > > > root@twins:/usr/src/linux-2.6# awk '/nfs/ {print $3}' /proc/self/mountinfo | while read bdi ; do ls -la /sys/class/bdi/${bdi}/ ; done > > ls: cannot access /sys/class/bdi/0:20/: No such file or directory > > total 0 > > drwxr-xr-x 3 root root 0 2012-03-27 23:18 . > > drwxr-xr-x 35 root root 0 2012-03-27 23:02 .. > > -rw-r--r-- 1 root root 4096 2012-04-14 14:22 max_ratio > > -rw-r--r-- 1 root root 4096 2012-04-14 14:22 min_ratio > > drwxr-xr-x 2 root root 0 2012-04-14 14:22 power > > -rw-r--r-- 1 root root 4096 2012-04-14 14:22 read_ahead_kb > > lrwxrwxrwx 1 root root 0 2012-03-27 23:18 subsystem -> ../../../../class/bdi > > -rw-r--r-- 1 root root 4096 2012-03-27 23:18 uevent > > Ok, got it. So /proc/self/mountinfo has the information about st_dev and > one can use that to reach to associated bdi. Thanks Peter.
Vivek, I noticed these lines in cfq code
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
Why not use bdi->dev->devt? The problem is that dev_name() will return "btrfs-X" for btrfs rather than "major:minor".
Thanks, Fengguang
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