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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-04-30 00:54:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:50 -0700
commit189d3c4a94ef19fca2a71a6a336e9fda900e25e7 (patch)
tree75c0de871fe9922885a2fa073f15806d829342fa /include
parentb6f2fcbcfca9db2bd7aa24940224fcd3bbdbb8aa (diff)
mm: bdi: allow setting a minimum for the bdi dirty limit
Under normal circumstances each device is given a part of the total write-back cache that relates to its current avg writeout speed in relation to the other devices. min_ratio - allows one to assign a minimum portion of the write-back cache to a particular device. This is useful in situations where you might want to provide a minimum QoS. (One request for this feature came from flash based storage people who wanted to avoid writing out at all costs - they of course needed some pdflush hacks as well) max_ratio - allows one to assign a maximum portion of the dirty limit to a particular device. This is useful in situations where you want to avoid one device taking all or most of the write-back cache. Eg. an NFS mount that is prone to get stuck, or a FUSE mount which you don't trust to play fair. Add "min_ratio" to /sys/class/bdi. This indicates the minimum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in min_ratio_store() - document new sysfs attribute Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/backing-dev.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 6d513666d45..9a8965518d1 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -51,6 +51,8 @@ struct backing_dev_info {
struct prop_local_percpu completions;
int dirty_exceeded;
+ unsigned int min_ratio;
+
struct device *dev;
};
@@ -137,6 +139,8 @@ static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
#endif
}
+int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
+
/*
* Flags in backing_dev_info::capability
* - The first two flags control whether dirty pages will contribute to the