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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
arch A pile of x86 fixes: 2020-05-31 10:45:11 -07:00
block Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT" 2020-05-28 13:20:39 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto gcc-10: avoid shadowing standard library 'free()' in crypto 2020-05-09 15:58:04 -07:00
Documentation checkpatch/coding-style: deprecate 80-column warning 2020-05-31 11:00:42 -07:00
drivers ubi: Select fastmap anchor PEBs considering wear level rules 2020-06-02 22:53:05 +02:00
fs Cache tiering and cap handling fixups, both marked for stable. 2020-05-29 13:59:54 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-31 10:16:53 -07:00
init A single fix for early boot crashes of kernels built with gcc10 and 2020-05-17 11:08:29 -07:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-14 10:00:35 -07:00
kernel A single scheduler fix preventing a crash in NUMA balancing. The 2020-05-31 10:43:17 -07:00
lib vsprintf: don't obfuscate NULL and error pointers 2020-05-19 11:35:38 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm,thp: stop leaking unreleased file pages 2020-05-28 11:35:40 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-31 10:16:53 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-15 13:10:06 -07:00
scripts checkpatch/coding-style: deprecate 80-column warning 2020-05-31 11:00:42 -07:00
security Merge branch 'for-5.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2020-05-27 10:58:19 -07:00
sound sound fixes for 5.7 (rc8 or final) 2020-05-29 13:31:01 -07:00
tools A pile of x86 fixes: 2020-05-31 10:45:11 -07:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: Introduce kvm_make_all_cpus_request_except() 2020-05-08 07:44:32 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-04-18 13:49:33 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
.mailmap i2c: use my kernel.org address from now on 2020-05-05 16:29:09 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2020-05-23 11:21:47 -07:00
Makefile Linux 5.7 2020-05-31 16:49:15 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.