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kernel: backport ubifs support for dirty_writeback_interval

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These patches were queued for 4.10. For possible use cases see added:
[PATCH] ubifs: Use dirty_writeback_interval value for wbuf timer

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki 2016-12-13 09:39:33 +01:00
parent 2ca4c74279
commit d6ef917bdb
2 changed files with 148 additions and 0 deletions
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82
target/linux/generic/patches-4.4/053-0001-ubifs-Drop-softlimit-and-delta-fields-from-struct-ub.patch Normal file
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@ -0,0 +1,82 @@
From 854826c9d526fd81077742c3b000e3f7fcaef3ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 20 Sep 2016 10:36:14 +0200
Subject: [PATCH] ubifs: Drop softlimit and delta fields from struct ubifs_wbuf
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Values of these fields are set during init and never modified. They are
used (read) in a single function only. There isn't really any reason to
keep them in a struct. It only makes struct just a bit bigger without
any visible gain.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/ubifs/io.c | 18 ++++++++++--------
fs/ubifs/ubifs.h | 5 -----
2 files changed, 10 insertions(+), 13 deletions(-)
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -452,16 +452,22 @@ static enum hrtimer_restart wbuf_timer_c
*/
static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
{
+ ktime_t softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
+ unsigned long long delta;
+
+ delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
+ delta *= 1000000000ULL;
+
ubifs_assert(!hrtimer_active(&wbuf->timer));
+ ubifs_assert(delta <= ULONG_MAX);
if (wbuf->no_timer)
return;
dbg_io("set timer for jhead %s, %llu-%llu millisecs",
dbg_jhead(wbuf->jhead),
- div_u64(ktime_to_ns(wbuf->softlimit), USEC_PER_SEC),
- div_u64(ktime_to_ns(wbuf->softlimit) + wbuf->delta,
- USEC_PER_SEC));
- hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta,
+ div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),
+ div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));
+ hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,
HRTIMER_MODE_REL);
}
@@ -1059,10 +1065,6 @@ int ubifs_wbuf_init(struct ubifs_info *c
hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
wbuf->timer.function = wbuf_timer_callback_nolock;
- wbuf->softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
- wbuf->delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
- wbuf->delta *= 1000000000ULL;
- ubifs_assert(wbuf->delta <= ULONG_MAX);
return 0;
}
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -668,9 +668,6 @@ typedef int (*ubifs_lpt_scan_callback)(s
* @io_mutex: serializes write-buffer I/O
* @lock: serializes @buf, @lnum, @offs, @avail, @used, @next_ino and @inodes
* fields
- * @softlimit: soft write-buffer timeout interval
- * @delta: hard and soft timeouts delta (the timer expire interval is @softlimit
- * and @softlimit + @delta)
* @timer: write-buffer timer
* @no_timer: non-zero if this write-buffer does not have a timer
* @need_sync: non-zero if the timer expired and the wbuf needs sync'ing
@@ -699,8 +696,6 @@ struct ubifs_wbuf {
int (*sync_callback)(struct ubifs_info *c, int lnum, int free, int pad);
struct mutex io_mutex;
spinlock_t lock;
- ktime_t softlimit;
- unsigned long long delta;
struct hrtimer timer;
unsigned int no_timer:1;
unsigned int need_sync:1;

66
target/linux/generic/patches-4.4/053-0002-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch Normal file
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From 1b7fc2c0069f3864a3dda15430b7aded31c0bfcc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 20 Sep 2016 10:36:15 +0200
Subject: [PATCH] ubifs: Use dirty_writeback_interval value for wbuf timer
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Right now wbuf timer has hardcoded timeouts and there is no place for
manual adjustments. Some projects / cases many need that though. Few
file systems allow doing that by respecting dirty_writeback_interval
that can be set using sysctl (dirty_writeback_centisecs).
Lowering dirty_writeback_interval could be some way of dealing with user
space apps lacking proper fsyncs. This is definitely *not* a perfect
solution but we don't have ideal (user space) world. There were already
advanced discussions on this matter, mostly when ext4 was introduced and
it wasn't behaving as ext3. Anyway, the final decision was to add some
hacks to the ext4, as trying to fix whole user space or adding new API
was pointless.
We can't (and shouldn't?) just follow ext4. We can't e.g. sync on close
as this would cause too many commits and flash wearing. On the other
hand we still should allow some trade-off between -o sync and default
wbuf timeout. Respecting dirty_writeback_interval should allow some sane
cutomizations if used warily.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/ubifs/io.c | 8 ++++----
fs/ubifs/ubifs.h | 4 ----
2 files changed, 4 insertions(+), 8 deletions(-)
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -452,11 +452,11 @@ static enum hrtimer_restart wbuf_timer_c
*/
static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
{
- ktime_t softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
- unsigned long long delta;
+ ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
+ unsigned long long delta = dirty_writeback_interval;
- delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
- delta *= 1000000000ULL;
+ /* centi to milli, milli to nano, then 10% */
+ delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
ubifs_assert(!hrtimer_active(&wbuf->timer));
ubifs_assert(delta <= ULONG_MAX);
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -106,10 +106,6 @@
*/
#define BGT_NAME_PATTERN "ubifs_bgt%d_%d"
-/* Write-buffer synchronization timeout interval in seconds */
-#define WBUF_TIMEOUT_SOFTLIMIT 3
-#define WBUF_TIMEOUT_HARDLIMIT 5
-
/* Maximum possible inode number (only 32-bit inodes are supported now) */
#define MAX_INUM 0xFFFFFFFF