[source] kernel: backport ubifs support for dirty_writeback_interval
LEDE Commits
lede-commits at lists.infradead.org
Tue Dec 13 00:50:57 PST 2016
rmilecki pushed a commit to source.git, branch master:
https://git.lede-project.org/d6ef917bdb8890c3392dae2a9ef3dce47118c798
commit d6ef917bdb8890c3392dae2a9ef3dce47118c798
Author: Rafał Miłecki <rafal at milecki.pl>
AuthorDate: Tue Dec 13 09:39:33 2016 +0100
kernel: backport ubifs support for dirty_writeback_interval
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 at milecki.pl>
---
...softlimit-and-delta-fields-from-struct-ub.patch | 82 ++++++++++++++++++++++
...irty_writeback_interval-value-for-wbuf-ti.patch | 66 +++++++++++++++++
2 files changed, 148 insertions(+)
diff --git a/target/linux/generic/patches-4.4/053-0001-ubifs-Drop-softlimit-and-delta-fields-from-struct-ub.patch b/target/linux/generic/patches-4.4/053-0001-ubifs-Drop-softlimit-and-delta-fields-from-struct-ub.patch
new file mode 100644
index 0000000..662584c
--- /dev/null
+++ b/target/linux/generic/patches-4.4/053-0001-ubifs-Drop-softlimit-and-delta-fields-from-struct-ub.patch
@@ -0,0 +1,82 @@
+From 854826c9d526fd81077742c3b000e3f7fcaef3ce Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal at 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 at milecki.pl>
+Reviewed-by: Boris Brezillon <boris.brezillon at free-electrons.com>
+Signed-off-by: Richard Weinberger <richard at 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;
diff --git a/target/linux/generic/patches-4.4/053-0002-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch b/target/linux/generic/patches-4.4/053-0002-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch
new file mode 100644
index 0000000..9313cd5
--- /dev/null
+++ b/target/linux/generic/patches-4.4/053-0002-ubifs-Use-dirty_writeback_interval-value-for-wbuf-ti.patch
@@ -0,0 +1,66 @@
+From 1b7fc2c0069f3864a3dda15430b7aded31c0bfcc Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal at 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 at milecki.pl>
+Reviewed-by: Boris Brezillon <boris.brezillon at free-electrons.com>
+Signed-off-by: Richard Weinberger <richard at 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
+
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