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author | 2006-03-24 03:15:48 -0800 | |
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committer | 2006-03-24 07:33:20 -0800 | |
commit | f6ef943813ac3085ece7252ea101d663581219f6 (patch) | |
tree | e32d3e57ba6ae235ec1f510b16d77fe9bfa8f96e | |
parent | [PATCH] free_uid() locking improvement (diff) | |
download | linux-f6ef943813ac3085ece7252ea101d663581219f6.tar.gz linux-f6ef943813ac3085ece7252ea101d663581219f6.tar.bz2 linux-f6ef943813ac3085ece7252ea101d663581219f6.zip |
[PATCH] Represent dirty_*_centisecs as jiffies internally
Make that the internal values for:
/proc/sys/vm/dirty_writeback_centisecs
/proc/sys/vm/dirty_expire_centisecs
are stored as jiffies instead of centiseconds. Let the sysctl interface do
the conversions with full precision using clock_t_to_jiffies, instead of
doing overflow-sensitive on-the-fly conversions every time the values are
used.
Cons: apparent precision loss if HZ is not a multiple of 100, because of
conversion back and forth. This is a common problem for all sysctl values
that use proc_dointvec_userhz_jiffies. (There is only one other in-tree
use, in net/core/neighbour.c.)
Signed-off-by: Bart Samwel <bart@samwel.tk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r-- | include/linux/writeback.h | 4 | ||||
-rw-r--r-- | kernel/sysctl.c | 10 | ||||
-rw-r--r-- | mm/page-writeback.c | 24 |
3 files changed, 19 insertions, 19 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index beaef5c7a0ea..609565961494 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -88,8 +88,8 @@ void throttle_vm_writeout(void); /* These are exported to sysctl. */ extern int dirty_background_ratio; extern int vm_dirty_ratio; -extern int dirty_writeback_centisecs; -extern int dirty_expire_centisecs; +extern int dirty_writeback_interval; +extern int dirty_expire_interval; extern int block_dump; extern int laptop_mode; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 32b48e8ee36e..817ba25517eb 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -742,18 +742,18 @@ static ctl_table vm_table[] = { { .ctl_name = VM_DIRTY_WB_CS, .procname = "dirty_writeback_centisecs", - .data = &dirty_writeback_centisecs, - .maxlen = sizeof(dirty_writeback_centisecs), + .data = &dirty_writeback_interval, + .maxlen = sizeof(dirty_writeback_interval), .mode = 0644, .proc_handler = &dirty_writeback_centisecs_handler, }, { .ctl_name = VM_DIRTY_EXPIRE_CS, .procname = "dirty_expire_centisecs", - .data = &dirty_expire_centisecs, - .maxlen = sizeof(dirty_expire_centisecs), + .data = &dirty_expire_interval, + .maxlen = sizeof(dirty_expire_interval), .mode = 0644, - .proc_handler = &proc_dointvec, + .proc_handler = &proc_dointvec_userhz_jiffies, }, { .ctl_name = VM_NR_PDFLUSH_THREADS, diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 945559fb63d2..e79107991d20 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -75,12 +75,12 @@ int vm_dirty_ratio = 40; * The interval between `kupdate'-style writebacks, in centiseconds * (hundredths of a second) */ -int dirty_writeback_centisecs = 5 * 100; +int dirty_writeback_interval = 5 * HZ; /* * The longest number of centiseconds for which data is allowed to remain dirty */ -int dirty_expire_centisecs = 30 * 100; +int dirty_expire_interval = 30 * HZ; /* * Flag that makes the machine dump writes/reads and block dirtyings. @@ -380,8 +380,8 @@ static DEFINE_TIMER(laptop_mode_wb_timer, laptop_timer_fn, 0, 0); * just walks the superblock inode list, writing back any inodes which are * older than a specific point in time. * - * Try to run once per dirty_writeback_centisecs. But if a writeback event - * takes longer than a dirty_writeback_centisecs interval, then leave a + * Try to run once per dirty_writeback_interval. But if a writeback event + * takes longer than a dirty_writeback_interval interval, then leave a * one-second gap. * * older_than_this takes precedence over nr_to_write. So we'll only write back @@ -406,9 +406,9 @@ static void wb_kupdate(unsigned long arg) sync_supers(); get_writeback_state(&wbs); - oldest_jif = jiffies - (dirty_expire_centisecs * HZ) / 100; + oldest_jif = jiffies - dirty_expire_interval; start_jif = jiffies; - next_jif = start_jif + (dirty_writeback_centisecs * HZ) / 100; + next_jif = start_jif + dirty_writeback_interval; nr_to_write = wbs.nr_dirty + wbs.nr_unstable + (inodes_stat.nr_inodes - inodes_stat.nr_unused); while (nr_to_write > 0) { @@ -425,7 +425,7 @@ static void wb_kupdate(unsigned long arg) } if (time_before(next_jif, jiffies + HZ)) next_jif = jiffies + HZ; - if (dirty_writeback_centisecs) + if (dirty_writeback_interval) mod_timer(&wb_timer, next_jif); } @@ -435,11 +435,11 @@ static void wb_kupdate(unsigned long arg) int dirty_writeback_centisecs_handler(ctl_table *table, int write, struct file *file, void __user *buffer, size_t *length, loff_t *ppos) { - proc_dointvec(table, write, file, buffer, length, ppos); - if (dirty_writeback_centisecs) { + proc_dointvec_userhz_jiffies(table, write, file, buffer, length, ppos); + if (dirty_writeback_interval) { mod_timer(&wb_timer, - jiffies + (dirty_writeback_centisecs * HZ) / 100); - } else { + jiffies + dirty_writeback_interval); + } else { del_timer(&wb_timer); } return 0; @@ -544,7 +544,7 @@ void __init page_writeback_init(void) if (vm_dirty_ratio <= 0) vm_dirty_ratio = 1; } - mod_timer(&wb_timer, jiffies + (dirty_writeback_centisecs * HZ) / 100); + mod_timer(&wb_timer, jiffies + dirty_writeback_interval); set_ratelimit(); register_cpu_notifier(&ratelimit_nb); } |