Patchwork UBI: Change the default percentage of reserved PEB

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Submitter Richard Genoud
Date June 29, 2012, 6:57 a.m.
Message ID <1340953061-15728-1-git-send-email-richard.genoud@gmail.com>
Download mbox | patch
Permalink /patch/168006/
State Accepted
Commit 54de1f1c44c3522dbdc2201be1f65e733526de51
Headers show

Comments

Richard Genoud - June 29, 2012, 6:57 a.m.
The actual value (1%) is too low for actual NAND devices, a huge
majority of device has 2% maximum bad blocks (SLC or MLC).
(Actually it's 20 blocks on a 1024 blocks device, 40/2048...)

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
---
 drivers/mtd/ubi/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
Artem Bityutskiy - June 29, 2012, 1:51 p.m.
On Fri, 2012-06-29 at 08:57 +0200, Richard Genoud wrote:
> The actual value (1%) is too low for actual NAND devices, a huge
> majority of device has 2% maximum bad blocks (SLC or MLC).
> (Actually it's 20 blocks on a 1024 blocks device, 40/2048...)
> 
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>

Thanks. But I'd like to wait a bit - Shmulik's point is fair and the
current way UBI reserves PEBs is probably not the right thing to do. If
we are going to change it, I'd like to have this patch to go together
with that change. Just because it is better to change the default
behavior once, than 2 times, to possibly upset/surprise users less
times :-)
Artem Bityutskiy - July 16, 2012, 6:31 a.m.
On Fri, 2012-06-29 at 16:51 +0300, Artem Bityutskiy wrote:
> On Fri, 2012-06-29 at 08:57 +0200, Richard Genoud wrote:
> > The actual value (1%) is too low for actual NAND devices, a huge
> > majority of device has 2% maximum bad blocks (SLC or MLC).
> > (Actually it's 20 blocks on a 1024 blocks device, 40/2048...)
> > 
> > Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> 
> Thanks. But I'd like to wait a bit - Shmulik's point is fair and the
> current way UBI reserves PEBs is probably not the right thing to do. If
> we are going to change it, I'd like to have this patch to go together
> with that change. Just because it is better to change the default
> behavior once, than 2 times, to possibly upset/surprise users less
> times :-)

Pushed to linux-ubi.git, thanks!

Patch

diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 738ee8d..ea4b95b 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -29,7 +29,7 @@  config MTD_UBI_WL_THRESHOLD
 
 config MTD_UBI_BEB_RESERVE
 	int "Percentage of reserved eraseblocks for bad eraseblocks handling"
-	default 1
+	default 2
 	range 0 25
 	help
 	  If the MTD device admits of bad eraseblocks (e.g. NAND flash), UBI