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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-04-30 00:54:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:50 -0700
commita42dde04152750426cc620fd277e80fffae2f65a (patch)
tree98cdf246280c59e0bf044ae6d2c229fc27b73203 /include/linux
parent189d3c4a94ef19fca2a71a6a336e9fda900e25e7 (diff)
downloadop-kernel-dev-a42dde04152750426cc620fd277e80fffae2f65a.zip
op-kernel-dev-a42dde04152750426cc620fd277e80fffae2f65a.tar.gz
mm: bdi: allow setting a maximum for the bdi dirty limit
Add "max_ratio" to /sys/class/bdi. This indicates the maximum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in max_ratio_store(). - export bdi_set_max_ratio() to modules - limit bdi_dirty with bdi->max_ratio - 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/linux')
-rw-r--r--include/linux/backing-dev.h2
-rw-r--r--include/linux/proportions.h13
2 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 9a89655..ad3271d 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -52,6 +52,7 @@ struct backing_dev_info {
int dirty_exceeded;
unsigned int min_ratio;
+ unsigned int max_ratio, max_prop_frac;
struct device *dev;
};
@@ -140,6 +141,7 @@ static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
}
int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
+int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
/*
* Flags in backing_dev_info::capability
diff --git a/include/linux/proportions.h b/include/linux/proportions.h
index 2c3b3ca..5afc1b2 100644
--- a/include/linux/proportions.h
+++ b/include/linux/proportions.h
@@ -78,6 +78,19 @@ void prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl)
}
/*
+ * Limit the time part in order to ensure there are some bits left for the
+ * cycle counter and fraction multiply.
+ */
+#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4)
+
+#define PROP_FRAC_SHIFT (BITS_PER_LONG - PROP_MAX_SHIFT - 1)
+#define PROP_FRAC_BASE (1UL << PROP_FRAC_SHIFT)
+
+void __prop_inc_percpu_max(struct prop_descriptor *pd,
+ struct prop_local_percpu *pl, long frac);
+
+
+/*
* ----- SINGLE ------
*/
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