The patch titled
mm: fix proc_dointvec_userhz_jiffies "breakage"
has been added to the -mm tree. Its filename is
mm-fix-proc_dointvec_userhz_jiffies-breakage.patch
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------------------------------------------------------
Subject: mm: fix proc_dointvec_userhz_jiffies "breakage"
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=9838
On i386, HZ=1000, jiffies_to_clock_t() converts time in a somewhat strange
way from the user's point of view:
# echo 500 >/proc/sys/vm/dirty_writeback_centisecs
# cat /proc/sys/vm/dirty_writeback_centisecs
499
So, we have 5000 jiffies converted to only 499 clock ticks and reported
back.
TICK_NSEC = 999848
ACTHZ = 256039
Keeping in-kernel variable in units passed from userspace will fix issue
of course, but this probably won't be right for every sysctl.
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/writeback.h | 4 ++--
kernel/sysctl.c | 2 +-
mm/page-writeback.c | 18 +++++++++---------
3 files changed, 12 insertions(+), 12 deletions(-)
diff -puN include/linux/writeback.h~mm-fix-proc_dointvec_userhz_jiffies-breakage include/linux/writeback.h
--- a/include/linux/writeback.h~mm-fix-proc_dointvec_userhz_jiffies-breakage
+++ a/include/linux/writeback.h
@@ -109,8 +109,8 @@ extern int dirty_background_ratio;
extern unsigned long dirty_background_bytes;
extern int vm_dirty_ratio;
extern unsigned long vm_dirty_bytes;
-extern int dirty_writeback_interval;
-extern int dirty_expire_interval;
+extern unsigned int dirty_writeback_interval;
+extern unsigned int dirty_expire_interval;
extern int vm_highmem_is_dirtyable;
extern int block_dump;
extern int laptop_mode;
diff -puN kernel/sysctl.c~mm-fix-proc_dointvec_userhz_jiffies-breakage kernel/sysctl.c
--- a/kernel/sysctl.c~mm-fix-proc_dointvec_userhz_jiffies-breakage
+++ a/kernel/sysctl.c
@@ -1044,7 +1044,7 @@ static struct ctl_table vm_table[] = {
.data = &dirty_expire_interval,
.maxlen = sizeof(dirty_expire_interval),
.mode = 0644,
- .proc_handler = &proc_dointvec_userhz_jiffies,
+ .proc_handler = &proc_dointvec,
},
{
.ctl_name = VM_NR_PDFLUSH_THREADS,
diff -puN mm/page-writeback.c~mm-fix-proc_dointvec_userhz_jiffies-breakage mm/page-writeback.c
--- a/mm/page-writeback.c~mm-fix-proc_dointvec_userhz_jiffies-breakage
+++ a/mm/page-writeback.c
@@ -92,14 +92,14 @@ int vm_dirty_ratio = 10;
unsigned long vm_dirty_bytes;
/*
- * The interval between `kupdate'-style writebacks, in jiffies
+ * The interval between `kupdate'-style writebacks
*/
-int dirty_writeback_interval = 5 * HZ;
+unsigned int dirty_writeback_interval = 5 * 100; /* sentiseconds */
/*
- * The longest number of jiffies for which data is allowed to remain dirty
+ * The longest time for which data is allowed to remain dirty
*/
-int dirty_expire_interval = 30 * HZ;
+unsigned int dirty_expire_interval = 30 * 100; /* sentiseconds */
/*
* Flag that makes the machine dump writes/reads and block dirtyings.
@@ -770,9 +770,9 @@ static void wb_kupdate(unsigned long arg
sync_supers();
- oldest_jif = jiffies - dirty_expire_interval;
+ oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval);
start_jif = jiffies;
- next_jif = start_jif + dirty_writeback_interval;
+ next_jif = start_jif + msecs_to_jiffies(dirty_writeback_interval * 10);
nr_to_write = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS) +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
@@ -801,9 +801,9 @@ 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_userhz_jiffies(table, write, file, buffer, length, ppos);
+ proc_dointvec(table, write, file, buffer, length, ppos);
if (dirty_writeback_interval)
- mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
+ mod_timer(&wb_timer, jiffies + msecs_to_jiffies(dirty_writeback_interval * 10));
else
del_timer(&wb_timer);
return 0;
@@ -905,7 +905,7 @@ void __init page_writeback_init(void)
{
int shift;
- mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
+ mod_timer(&wb_timer, jiffies + msecs_to_jiffies(dirty_writeback_interval * 10));
writeback_set_ratelimit();
register_cpu_notifier(&ratelimit_nb);
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
origin.patch
xtensa-fix-compilation-somewhat.patch
devpts-remove-graffiti.patch
linux-next.patch
proc-tty-add-struct-tty_operations-proc_fops.patch
proc-tty-switch-cyclades-to-proc_fops.patch
proc-tty-switch-ip2-to-proc_fops.patch
proc-tty-switch-istallion-to-proc_fops.patch
proc-tty-switch-synclink_cs-to-proc_fops.patch
proc-tty-switch-stallion-to-proc_fops.patch
proc-tty-switch-synclink-to-proc_fops.patch
proc-tty-switch-synclink_gt-to-proc_fops.patch
proc-tty-switch-synclinkmp-to-proc_fops.patch
proc-tty-switch-sdio_uart-to-proc_fops.patch
proc-tty-switch-serial_core-to-proc_fops.patch
proc-tty-switch-usb-serial-to-proc_fops.patch
proc-tty-switch-ircomm-to-proc_fops.patch
proc-tty-switch-amiserial-to-proc_fops.patch
proc-tty-switch-ia64-simserial-to-proc_fops.patch
proc-tty-switch-xtensa-iss-console-to-proc_fops.patch
proc-tty-remove-struct-tty_operations-read_proc.patch
memdup_user-introduce.patch
mm-fix-proc_dointvec_userhz_jiffies-breakage.patch
softirq-introduce-statistics-for-softirq.patch
proc-export-statistics-for-softirq-to-proc.patch
proc-export-statistics-for-softirq-to-proc-fix.patch
proc-update-document-for-proc-softirqs-and-proc-stat.patch
proc_sysctl-use-config_proc_sysctl-around-ipc-and-utsname-proc_handlers.patch
namespaces-move-proc_net_get_sb-to-a-generic-fs-superc-helper.patch
namespaces-move-proc_net_get_sb-to-a-generic-fs-superc-helper-fix.patch
namespaces-mqueue-ns-move-mqueue_mnt-into-struct-ipc_namespace.patch
namespaces-ipc-namespaces-implement-support-for-posix-msqueues.patch
namespaces-ipc-namespaces-implement-support-for-posix-msqueues-initialize-init_ipc_nscount-to-1.patch
namespaces-mqueue-namespace-adapt-sysctl.patch
namespaces-mqueue-namespace-adapt-sysctl-update.patch
namespaces-mqueue-namespace-adapt-sysctl-update-fix.patch
--
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