linux_dsm_epyc7002/drivers/mtd
Arne Edholm 4b68bf9a69 ubi: Select fastmap anchor PEBs considering wear level rules
There is a risk that the fastmap anchor PEB is alternating between
just two PEBs, the current anchor and the previous anchor that was just
deleted. As the fastmap pools gets the first take on free PEBs, the
pools may leave no free PEBs to be selected as the new anchor,
resulting in the two PEBs alternating behaviour. If the anchor PEBs gets
a high erase count the PEBs will not be used by the pools but remain in
ubi->free, even more increasing the likelihood they will be used as
anchors.

Getting stuck using only a couple of PEBs continuously will result in an
uneven wear, eventually leading to failure.

To fix this:

- Choose the fastmap anchor when the most free PEBs are available. This is
  during rebuilding of the fastmap pools, after the unused pool PEBs are
  added to ubi->free but before the pools are populated again from the
  free PEBs. Also reserve an additional second best PEB as a candidate
  for the next time the fast map anchor is updated. If a better PEB is
  found the next time the fast map anchor is updated, the candidate is
  made available for building the pools.

- Enable anchor move within the anchor area again as it is useful for
  distributing wear.

- The anchor candidate for the next fastmap update is the most suited free
  PEB. Check this PEB's erase count during wear leveling. If the wear
  leveling limit is exceeded, the PEB is considered unsuitable for now. As
  all other non used anchor area PEBs should be even worse, free up the
  used anchor area PEB with the lowest erase count.

Signed-off-by: Arne Edholm <arne.edholm@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2020-06-02 22:53:05 +02:00
..
chips mtd: Convert fallthrough comments into statements 2020-03-30 10:14:54 +02:00
devices mtd: Convert fallthrough comments into statements 2020-03-30 10:14:54 +02:00
hyperbus mtd: hyperbus: move direct mapping setup to AM654 HBMC driver 2020-03-03 10:13:11 +05:30
lpddr mtd: Convert fallthrough comments into statements 2020-03-30 10:14:54 +02:00
maps mtd: Convert fallthrough comments into statements 2020-03-30 10:14:54 +02:00
nand mtd:rawnand: brcmnand: Fix PM resume crash 2020-05-19 10:24:49 +02:00
parsers mtd: sharpslpart: Fix unsigned comparison to zero 2020-01-21 20:00:34 +01:00
spi-nor mtd: spi-nor: Compile files in controllers/ directory 2020-04-09 22:00:13 +02:00
tests treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 326 2019-06-05 17:37:06 +02:00
ubi ubi: Select fastmap anchor PEBs considering wear level rules 2020-06-02 22:53:05 +02:00
ftl.c
inftlcore.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
inftlmount.c mtd: fix spelling mistake "BlockMultiplerBits" -> "BlockMultiplierBits" 2020-03-11 14:49:30 +01:00
Kconfig mtd: parsers: Move CMDLINE parser 2019-09-15 23:50:50 +02:00
Makefile mtd: parsers: Move CMDLINE parser 2019-09-15 23:50:50 +02:00
mtd_blkdevs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102 2019-05-24 17:39:00 +02:00
mtdblock_ro.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102 2019-05-24 17:39:00 +02:00
mtdblock.c mtd: Fix issue where write_cached_data() fails but write() still returns success 2020-03-24 23:02:30 +01:00
mtdchar.c mtd: implement proper partition handling 2020-03-11 14:49:30 +01:00
mtdconcat.c mtd: concat: Fix a comment referring to an unknown symbol 2020-01-27 17:45:31 +01:00
mtdcore.c mtd: Fix mtd not registered due to nvmem name collision 2020-05-18 22:04:07 +02:00
mtdcore.h mtd: Provide fs_context-aware mount_mtd() replacement 2019-09-05 14:34:23 -04:00
mtdoops.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
mtdpart.c mtd: implement proper partition handling 2020-03-11 14:49:30 +01:00
mtdsuper.c mtd: Kill mount_mtd() 2019-09-05 14:34:26 -04:00
mtdswap.c mtd: no need to check return value of debugfs_create functions 2019-11-14 10:57:38 +01:00
nftlcore.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
nftlmount.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
rfd_ftl.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sm_ftl.c mtd: sm_ftl: fix NULL pointer warning 2020-01-09 20:09:55 +01:00
sm_ftl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
ssfdc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00