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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-04-30 00:54:36 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 08:29:50 -0700 |
commit | a42dde04152750426cc620fd277e80fffae2f65a (patch) | |
tree | 98cdf246280c59e0bf044ae6d2c229fc27b73203 /mm | |
parent | 189d3c4a94ef19fca2a71a6a336e9fda900e25e7 (diff) | |
download | linux-a42dde04152750426cc620fd277e80fffae2f65a.tar.bz2 |
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 'mm')
-rw-r--r-- | mm/backing-dev.c | 21 | ||||
-rw-r--r-- | mm/page-writeback.c | 41 |
2 files changed, 56 insertions, 6 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 4967fb176e53..08361b6aad50 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -73,6 +73,24 @@ static ssize_t min_ratio_store(struct device *dev, } BDI_SHOW(min_ratio, bdi->min_ratio) +static ssize_t max_ratio_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + char *end; + unsigned int ratio; + ssize_t ret = -EINVAL; + + ratio = simple_strtoul(buf, &end, 10); + if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { + ret = bdi_set_max_ratio(bdi, ratio); + if (!ret) + ret = count; + } + return ret; +} +BDI_SHOW(max_ratio, bdi->max_ratio) + #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) static struct device_attribute bdi_dev_attrs[] = { @@ -82,6 +100,7 @@ static struct device_attribute bdi_dev_attrs[] = { __ATTR_RO(dirty_kb), __ATTR_RO(bdi_dirty_kb), __ATTR_RW(min_ratio), + __ATTR_RW(max_ratio), __ATTR_NULL, }; @@ -147,6 +166,8 @@ int bdi_init(struct backing_dev_info *bdi) bdi->dev = NULL; bdi->min_ratio = 0; + bdi->max_ratio = 100; + bdi->max_prop_frac = PROP_FRAC_BASE; for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 4ac077f4269c..2a9942f5387c 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -164,7 +164,8 @@ int dirty_ratio_handler(struct ctl_table *table, int write, */ static inline void __bdi_writeout_inc(struct backing_dev_info *bdi) { - __prop_inc_percpu(&vm_completions, &bdi->completions); + __prop_inc_percpu_max(&vm_completions, &bdi->completions, + bdi->max_prop_frac); } static inline void task_dirty_inc(struct task_struct *tsk) @@ -254,16 +255,42 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) unsigned long flags; spin_lock_irqsave(&bdi_lock, flags); - min_ratio -= bdi->min_ratio; - if (bdi_min_ratio + min_ratio < 100) { - bdi_min_ratio += min_ratio; - bdi->min_ratio += min_ratio; - } else + if (min_ratio > bdi->max_ratio) { ret = -EINVAL; + } else { + min_ratio -= bdi->min_ratio; + if (bdi_min_ratio + min_ratio < 100) { + bdi_min_ratio += min_ratio; + bdi->min_ratio += min_ratio; + } else { + ret = -EINVAL; + } + } + spin_unlock_irqrestore(&bdi_lock, flags); + + return ret; +} + +int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) +{ + unsigned long flags; + int ret = 0; + + if (max_ratio > 100) + return -EINVAL; + + spin_lock_irqsave(&bdi_lock, flags); + if (bdi->min_ratio > max_ratio) { + ret = -EINVAL; + } else { + bdi->max_ratio = max_ratio; + bdi->max_prop_frac = (PROP_FRAC_BASE * max_ratio) / 100; + } spin_unlock_irqrestore(&bdi_lock, flags); return ret; } +EXPORT_SYMBOL(bdi_set_max_ratio); /* * Work out the current dirty-memory clamping and background writeout @@ -365,6 +392,8 @@ get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty, bdi_dirty *= numerator; do_div(bdi_dirty, denominator); bdi_dirty += (dirty * bdi->min_ratio) / 100; + if (bdi_dirty > (dirty * bdi->max_ratio) / 100) + bdi_dirty = dirty * bdi->max_ratio / 100; *pbdi_dirty = bdi_dirty; clip_bdi_dirty_limit(bdi, dirty, pbdi_dirty); |