Both recompress and writeback soon will unlock slots during processing,
which makes things too complex wrt possible race-conditions. We still
want to clear PP_SLOT in slot_free, because this is how we figure out that
slot that was selected for post-processing has been released under us and
when we start post-processing we check if slot still has PP_SLOT set. At
the same time, theoretically, we can have something like this:
CPU0 CPU1
recompress
scan slots
set PP_SLOT
unlock slot
slot_free
clear PP_SLOT
allocate PP_SLOT
writeback
scan slots
set PP_SLOT
unlock slot
select PP-slot
test PP_SLOT
So recompress will not detect that slot has been re-used and re-selected
for concurrent writeback post-processing.
Make sure that we only permit on post-processing operation at a time. So
now recompress and writeback post-processing don't race against each
other, we only need to handle slot re-use (slot_free and write), which is
handled individually by each pp operation.
Having recompress and writeback competing for the same slots is not
exactly good anyway (can't imagine anyone doing that).
Link: https://lkml.kernel.org/r/20240917021020.883356-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
recompress device attribute supports alg=NAME parameter so that we can
specify only one particular algorithm we want to perform recompression
with. However, with algo params we now can have several exactly same
secondary algorithms but each with its own params tuning (e.g. priority 1
configured to use more aggressive level, and priority 2 configured to use
a pre-trained dictionary). Support priority=NUM parameter so that we can
correctly determine which secondary algorithm we want to use.
Link: https://lkml.kernel.org/r/20240902105656.1383858-25-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This attribute is used to setup compression algorithms' parameters, so we
can tweak algorithms' characteristics. At this point only 'level' is
supported (to be extended in the future).
Each call sets up parameters for one particular algorithm, which should be
specified either by the algorithm's priority or algo name. This is
expected to be called after corresponding algorithm is selected via
comp_algorithm or recomp_algorithm.
echo "priority=0 level=1" > /sys/block/zram0/algorithm_params
or
echo "algo=zstd level=1" > /sys/block/zram0/algorithm_params
Link: https://lkml.kernel.org/r/20240902105656.1383858-16-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Moving to custom backends implementation gives us ability to have our own
minimalistic and extendable API, and algorithms tunings becomes possible.
The list of compression backends is empty at this point, we will add
backends in the followup patches.
Link: https://lkml.kernel.org/r/20240902105656.1383858-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Introduce "max_pages" param to recompress device attribute which sets an
upper limit on the number of entries (pages) zram attempts to recompress
(in this particular recompression call). S/W recompression can be quite
expensive so limiting the number of pages recompress touches can be quite
helpful.
Link: https://lkml.kernel.org/r/20240329094050.2815699-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
ZRAM_MEMORY_TRACKING enables two features:
- per-entry ac-time tracking
- debugfs interface
The latter one is the reason why memory-tracking depends on DEBUG_FS,
while the former one is used far beyond debugging these days. Namely
ac-time is used for fine grained writeback of idle entries (pages).
Move ac-time tracking under its own config option so that it can be
enabled (along with writeback) on systems without DEBUG_FS.
[senozhatsky@chromium.org: ifdef fixup, per Dmytro]
Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
While the sourceforge site for userspace NBD still exists, the code
repository moved to github several years ago. Then with a recent
patch[1], the github landing page contains just as much information as
the sourceforge page, so we might as well point to a single location
that also provides the code.
[1] https://lists.debian.org/nbd/2023/03/msg00051.html
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20230410180611.1051618-5-eblake@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove PARIDE core and high level protocols, taking care not to break
low-level drivers (used by pata_parport). Also update documentation.
Signed-off-by: Ondrej Zary <linux@zary.sk>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
The pata_parport is a libata-based replacement of the old PARIDE
subsystem - driver for parallel port IDE devices.
It uses the original paride low-level protocol drivers but does not
need the high-level drivers (pd, pcd, pf, pt, pg). The IDE devices
behind parallel port adapters are handled by the ATA layer.
This will allow paride and its high-level drivers to be removed.
Unfortunately, libata drivers cannot sleep so pata_parport claims
parport before activating the ata host and keeps it claimed (and
protocol connected) until the ata host is removed. This means that
no devices can be chained (neither other pata_parport devices nor
a printer).
paride and pata_parport are mutually exclusive because the compiled
protocol drivers are incompatible.
Tested with:
- Imation SuperDisk LS-120 and HP C4381A (EPAT)
- Freecom Parallel CD (FRPW)
- Toshiba Mobile CD-RW 2793008 w/Freecom Parallel Cable rev.903 (FRIQ)
- Backpack CD-RW 222011 and CD-RW 19350 (BPCK6)
The following bugs in low-level protocol drivers were found and will
be fixed later:
Note: EPP-32 mode is buggy in EPAT - and also in all other protocol
drivers - they don't handle non-multiple-of-4 block transfers
correctly. This causes problems with LS-120 drive.
There is also another bug in EPAT: EPP modes don't work unless a 4-bit
or 8-bit mode is used first (probably some initialization missing?).
Once the device is initialized, EPP works until power cycle.
So after device power on, you have to:
echo "parport0 epat 0" >/sys/bus/pata_parport/new_device
echo pata_parport.0 >/sys/bus/pata_parport/delete_device
echo "parport0 epat 4" >/sys/bus/pata_parport/new_device
(autoprobe will initialize correctly as it tries the slowest modes
first but you'll get the broken EPP-32 mode)
Note: EPP modes are buggy in FRPW, only modes 0 and 1 work.
Signed-off-by: Ondrej Zary <linux@zary.sk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Add a new flag to zram block state that shows if the page is
incompressible: that none of the algorithm (including secondary ones)
could compress it.
Link: https://lkml.kernel.org/r/20221109115047.2921851-14-senozhatsky@chromium.org
Suggested-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a new flag to zram block state that shows if the page was recompressed
(using alternative compression algorithm).
Link: https://lkml.kernel.org/r/20221109115047.2921851-6-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
tux logo which, I'm assured, we're going to want.
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Merge tag 'docs-5.19-2' of git://git.lwn.net/linux
Pull documentation fixes from Jonathan Corbet:
"A handful of late-arriving documentation fixes and the addition of an
SVG tux logo which, I'm assured, we're going to want"
* tag 'docs-5.19-2' of git://git.lwn.net/linux:
documentation: Format button_dev as a pointer.
docs: add SVG version of the Linux logo
docs: move Linux logo into a new `images` folder
docs: blockdev: change title to match section content
docs/conf.py: Cope with removal of language=None in Sphinx 5.0.0
This index.rst was added in commit
39443104c7 docs: blockdev: convert to ReST
It appears that the title from the RapidIO index page was copied. This
title does not match the content of this directory. Change it to match.
Signed-off-by: Joel Colledge <joel.colledge@linbit.com>
Link: https://lore.kernel.org/r/20220530142849.717-1-joel.colledge@linbit.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Today it's only possible to write back as a page, idle, or huge. A user
might want to writeback pages which are huge and idle first as these idle
pages do not require decompression and make a good first pass for
writeback.
Idle writeback specifically has the advantage that a refault is unlikely
given that the page has been swapped for some amount of time without being
refaulted.
Huge writeback has the advantage that you're guaranteed to get the maximum
benefit from a single page writeback, that is, you're reclaiming one full
page of memory. Pages which are compressed in zram being written back
result in some benefit which is always less than a page size because of
the fact that it was compressed.
The primary use of this is for minimizing refaults in situations where the
device has to be sensitive to storage endurance. On ChromeOS we have
devices with slow eMMC and repeated writes and refaults can negatively
affect performance and endurance.
Link: https://lkml.kernel.org/r/20220322215821.1196994-1-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This fixes some simple grammar errors in the documentation for zram,
specifically errors in the optional feature section of the zram
documentation.
Signed-off-by: Ethan Dye <mrtops03@gmail.com>
Link: https://lore.kernel.org/r/20220207235442.95090-1-mrtops03@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
While node-states-8.dot has two digraphs, the dot(1) command can
not properly handle multiple graphs in a DOT file and the
kernel-doc page at
https://www.kernel.org/doc/html/latest/admin-guide/blockdev/drbd/figures.html
fails to render the graphs.
It turned out that the digraph of node_states can be removed.
Quote from Joel's reflection:
On reflection, the digraph node_states can be removed entirely.
It is too basic to contain any useful information. In addition
it references "ioctl_set_state". The ioctl configuration
interface for DRBD has long been removed. In fact, it was never
in the upstream version of DRBD.
Remove node_states and rename the DOT file peer_states-8.dot.
Suggested-by: Joel Colledge <joel.colledge@linbit.com>
Acked-by: Joel Colledge <joel.colledge@linbit.com>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Link: https://lore.kernel.org/r/7df04f45-8746-e666-1a9d-a998f1ab1f91@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This change introduces an aged idle interface to the existing idle sysfs
file for zram.
When CONFIG_ZRAM_MEMORY_TRACKING is enabled the idle file now also
accepts an integer argument. This integer is the age (in seconds) of
pages to mark as idle. The idle file still supports 'all' as it always
has. This new approach allows for much more control over which pages
get marked as idle.
[bgeffon@google.com: use IS_ENABLED and cleanup comment]
Link: https://lkml.kernel.org/r/20210924161128.1508015-1-bgeffon@google.com
[bgeffon@google.com: Sergey's cleanup suggestions]
Link: https://lkml.kernel.org/r/20210929143056.13067-1-bgeffon@google.com
Link: https://lkml.kernel.org/r/20210923130115.1344361-1-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Jesse Barnes <jsbarnes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
- a few random little subsystems
- almost all of the MM patches which are staged ahead of linux-next
material. I'll trickle to post-linux-next work in as the dependents
get merged up.
Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
mm: cleanup kstrto*() usage
mm: fix fall-through warnings for Clang
mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
mm:backing-dev: use sysfs_emit in macro defining functions
mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
mm: use sysfs_emit for struct kobject * uses
mm: fix kernel-doc markups
zram: break the strict dependency from lzo
zram: add stat to gather incompressible pages since zram set up
zram: support page writeback
mm/process_vm_access: remove redundant initialization of iov_r
mm/zsmalloc.c: rework the list_add code in insert_zspage()
mm/zswap: move to use crypto_acomp API for hardware acceleration
mm/zswap: fix passing zero to 'PTR_ERR' warning
mm/zswap: make struct kernel_param_ops definitions const
userfaultfd/selftests: hint the test runner on required privilege
userfaultfd/selftests: fix retval check for userfaultfd_open()
userfaultfd/selftests: always dump something in modes
userfaultfd: selftests: make __{s,u}64 format specifiers portable
...
Currently, zram supports the stat via /sys/block/zram/mm_stat to represent
how many of incompressible pages are stored at the moment but it couldn't
show how many times incompressible pages were wrote down since zram set
up. It's also good indication to see how zram is effective in the system.
Link: https://lkml.kernel.org/r/20201130201907.1284910-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is demand to writeback specific process pages to backing store
instead of all idles pages in the system due to storage wear out concerns
and to launching latency of apps which are most of the time idle but are
critical for resume latency.
This patch extends the writeback knob to support a specific page
writeback.
Link: https://lkml.kernel.org/r/20201020190506.3758660-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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:
If not .svg:
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/20200627103111.71771-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
sysfs node for huge page writeback is writeback rather than write.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20200120102949.12132-1-zbestahu@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
All those new files I added are under GPL v2.0 license.
Add the corresponding SPDX headers to them.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
