Commit Graph

13 Commits

Author SHA1 Message Date
Linus Torvalds
ee2fe81cdc Merge tag 'docs-6.18' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
 "It has been a relatively busy cycle in docsland, with changes all
  over:

   - Bring the kernel memory-model docs into the Sphinx build in the
     "literal include" mode.

   - Lots of build-infrastructure work, further cleaning up long-term
     kernel-doc technical debt. The sphinx-pre-install tool has been
     converted to Python and updated for current systems.

   - A new tool to detect when documents have been moved and generate
     HTML redirects; this can be used on kernel.org (or any other site
     hosting the rendered docs) to avoid breaking links.

   - Automated processing of the YAML files describing the netlink
     protocol.

   - A significant update of the maintainer's PGP guide.

  ... and a seemingly endless series of typo fixes, build-problem fixes,
  etc"

* tag 'docs-6.18' of git://git.lwn.net/linux: (193 commits)
  Documentation/features: Update feature lists for 6.17-rc7
  docs: remove cdomain.py
  Documentation/process: submitting-patches: fix typo in "were do"
  docs: dev-tools/lkmm: Fix typo of missing file extension
  Documentation: trace: histogram: Convert ftrace docs cross-reference
  Documentation: trace: histogram-design: Wrap introductory note in note:: directive
  Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram
  Documentation: trace: histogram-design: Trim trailing vertices in diagram explanation text
  Documentation: trace: histogram: Fix histogram trigger subsection number order
  docs: driver-api: fix spelling of "buses".
  Documentation: fbcon: Use admonition directives
  Documentation: fbcon: Reindent 8th step of attach/detach/unload
  Documentation: fbcon: Add boot options and attach/detach/unload section headings
  docs: filesystems: sysfs: add remaining top level sysfs directory descriptions
  docs: filesystems: sysfs: clarify symlink destinations in dev and bus/devices descriptions
  docs: filesystems: sysfs: remove top level sysfs net directory
  docs: maintainer: Fix ambiguous subheading formatting
  docs: kdoc: a few more dump_typedef() tweaks
  docs: kdoc: remove redundant comment stripping in dump_typedef()
  docs: kdoc: remove some dead code in dump_typedef()
  ...
2025-10-03 17:16:13 -07:00
Yu Kuai
5ab829f197 md/md-llbitmap: introduce new lockless bitmap
Redundant data is used to enhance data fault tolerance, and the storage
method for redundant data vary depending on the RAID levels. And it's
important to maintain the consistency of redundant data.

Bitmap is used to record which data blocks have been synchronized and which
ones need to be resynchronized or recovered. Each bit in the bitmap
represents a segment of data in the array. When a bit is set, it indicates
that the multiple redundant copies of that data segment may not be
consistent. Data synchronization can be performed based on the bitmap after
power failure or readding a disk. If there is no bitmap, a full disk
synchronization is required.

Due to known performance issues with md-bitmap and the unreasonable
implementations:

 - self-managed IO submitting like filemap_write_page();
 - global spin_lock

I have decided not to continue optimizing based on the current bitmap
implementation, this new bitmap is invented without locking from IO fast
path and can be used with fast disks.

For designs and details, see the comments in drivers/md-llbitmap.c.

Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-12-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06 17:27:51 +08:00
Yu Kuai
fb8cc3b0d9 md/md-bitmap: delay registration of bitmap_ops until creating bitmap
Currently bitmap_ops is registered while allocating mddev, this is fine
when there is only one bitmap_ops.

Delay setting bitmap_ops until creating bitmap, so that user can choose
which bitmap to use before running the array.

Link: https://lore.kernel.org/linux-raid/20250721171557.34587-7-yukuai@kernel.org
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Li Nan <linan122@huawei.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
2025-09-06 17:19:19 +08:00
Yu Kuai
180b82c1c7 md/md-bitmap: add a new sysfs api bitmap_type
The api will be used by mdadm to set bitmap_type while creating new array
or assembling array, prepare to add a new bitmap.

Currently available options are:

cat /sys/block/md0/md/bitmap_type
none [bitmap]

Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-6-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06 17:19:04 +08:00
Vivek Alurkar
ddfaddc277 Fix typo in RAID arrays documentation
Changed "write-throuth" to "write-through".

Signed-off-by: Vivek Alurkar <primalkenja@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250821051622.8341-2-primalkenja@gmail.com
2025-08-29 16:29:18 -06:00
Randy Dunlap
dbeb56fe80 Documentation: admin-guide: correct spelling
Correct spelling problems for Documentation/admin-guide/ as reported
by codespell.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: dm-devel@redhat.com
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230129231053.20863-2-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-02-02 11:04:42 -07:00
Andrew Klychkov
751d5b2741 Documentation: fix multiple typos found in the admin-guide subdirectory
Fix thirty five typos in dm-integrity.rst, dm-raid.rst, dm-zoned.rst,
verity.rst, writecache.rst, tsx_async_abort.rst, md.rst, bttv.rst,
dvb_references.rst, frontend-cardlist.rst, gspca-cardlist.rst, ipu3.rst,
remote-controller.rst, mm/index.rst, numaperf.rst, userfaultfd.rst,
module-signing.rst, imx-ddr.rst, intel-speed-select.rst,
intel_pstate.rst, ramoops.rst, abi.rst, kernel.rst, vm.rst

Signed-off-by: Andrew Klychkov <andrew.a.klychkov@gmail.com>
Link: https://lore.kernel.org/r/20201204072848.GA49895@spblnx124.lan
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-12-08 10:27:56 -07:00
Sebastian Parschauer
ec164d07aa md: register new md sysfs file 'uuid' read-only
Report the UUID of the MD array in the following format:
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

This is useful if you don't want to wait for udev to identify array.
And it is also easy for script to monitor it with the format.

Signed-off-by: Sebastian Parschauer <s.parschauer@gmx.de>
[Guoqing: mention the change in md.rst]
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-08-02 23:03:51 -07:00
Alexander A. Klimov
93431e0607 Replace HTTP links with HTTPS ones: documentation
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  For each line:
    If doesn't contain `\bxmlns\b`:
      For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
        If both the HTTP and HTTPS versions
        return 200 OK and serve the same content:
          Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200526060544.25127-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-08 09:30:19 -06:00
Mariusz Dabrowski
a596d08677 raid5: set write hint for PPL
When the Partial Parity Log is enabled, circular buffer is used to store
PPL data. Each write to RAID device causes overwrite of data in this buffer
so some write_hint can be set to those request to help drives handle
garbage collection. This patch adds new sysfs attribute which can be used
to specify which write_hint should be assigned to PPL.

Acked-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2019-03-12 10:15:18 -07:00
Artur Paszkiewicz
664aed0444 md: add sysfs entries for PPL
Add 'consistency_policy' attribute for array. It indicates how the array
maintains consistency in case of unexpected shutdown.

Add 'ppl_sector' and 'ppl_size' for rdev, which describe the location
and size of the PPL space on the device. They can't be changed for
active members if the array is started and PPL is enabled, so in the
setter functions only basic checks are performed. More checks are done
in ppl_validate_rdev() when starting the log.

These attributes are writable to allow enabling PPL for external
metadata arrays and (later) to enable/disable PPL for a running array.

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16 16:55:55 -07:00
Shaohua Li
5a6265f9cd MD: add doc for raid5-cache
I'm starting document of the raid5-cache feature. Please note this is a
kernel doc instead of a mdadm manual, so I don't add the details about
how to use the feature in mdadm side.

Cc: NeilBrown <neilb@suse.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-02-13 09:17:54 -08:00
Mauro Carvalho Chehab
9d85025b04 docs-rst: create an user's manual book
Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters
on an user's manual book.

As we'll be numbering the user's manual, remove the manual
numbering from SecurityBugs.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-10-24 08:12:35 -02:00