The patch titled
jffs2: force the jffs2 GC daemon to behave a bit better
has been removed from the -mm tree. Its filename was
jffs2-force-the-jffs2-gc-daemon-to-behave-a-bit-better.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: jffs2: force the jffs2 GC daemon to behave a bit better
From: Andres Salomon <dilinger@xxxxxxxxxx>
I've noticed some pretty poor behavior on OLPC machines after bootup, when
gdm/X are starting. The GCD monopolizes the scheduler (which in turns
means it gets to do more nand i/o), which results in processes taking much
much longer than they should to start.
As an example, on an OLPC machine going from OFW to a usable X (via
auto-login gdm) takes 2m 30s. The majority of this time is consumed by
the switch into graphical mode. With this patch, we cut a full 60s off of
bootup time. After bootup, things are much snappier as well.
Note that we have seen a CRC node error with this patch that causes the machine
to fail to boot, but we've also seen that problem without this patch.
Signed-off-by: Andres Salomon <dilinger@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/jffs2/background.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff -puN fs/jffs2/background.c~jffs2-force-the-jffs2-gc-daemon-to-behave-a-bit-better fs/jffs2/background.c
--- a/fs/jffs2/background.c~jffs2-force-the-jffs2-gc-daemon-to-behave-a-bit-better
+++ a/fs/jffs2/background.c
@@ -95,13 +95,17 @@ static int jffs2_garbage_collect_thread(
spin_unlock(&c->erase_completion_lock);
- /* This thread is purely an optimisation. But if it runs when
- other things could be running, it actually makes things a
- lot worse. Use yield() and put it at the back of the runqueue
- every time. Especially during boot, pulling an inode in
- with read_inode() is much preferable to having the GC thread
- get there first. */
- yield();
+ /* Problem - immediately after bootup, the GCD spends a lot
+ * of time in places like jffs2_kill_fragtree(); so much so
+ * that userspace processes (like gdm and X) are starved
+ * despite plenty of cond_resched()s and renicing. Yield()
+ * doesn't help, either (presumably because userspace and GCD
+ * are generally competing for a higher latency resource -
+ * disk).
+ * This forces the GCD to slow the hell down. Pulling an
+ * inode in with read_inode() is much preferable to having
+ * the GC thread get there first. */
+ schedule_timeout_interruptible(msecs_to_jiffies(50));
/* Put_super will send a SIGKILL and then wait on the sem.
*/
_
Patches currently in -mm which might be from dilinger@xxxxxxxxxx are
linux-next.patch
drivers-video-sgivwfbc-fix-memory-leaks-in-removal-path.patch
tdfxfb-fix-memory-leaks-in-removal-path.patch
tridentfb-fix-memory-leaks-in-removal-path.patch
vfb-fix-memory-leaks-in-removal-path.patch
skeletonfb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
sm501fb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
sstfb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
stifb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
valkyriefb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
sunxvr500-fix-cmap-memory-leaks.patch
tgafb-fix-cmap-memory-leak.patch
68328fb-fix-cmap-memory-leaks.patch
amba-clcd-fix-cmap-memory-leaks.patch
amifb-check-fb_alloc_cmap-return-value-and-handle-failure-properly.patch
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