A pile of small fixes:
- don't quote terms like vanilla, mainline, and stable, unless in they
occur in places where readers new to the kernel might see them for the
first time
- make people rule out that vendor patches are interfering if they face
a regression in a stable or longterm kernel they saw in a vendor
kernel for the first time
- s/bugs/issues/ in a selected spots
- exchange two headlines that got mixed up somehow
- add a few links to some of the steps in the guide
- Greg mentioned sending reports to the stable mailing list is
sufficient, so remove the "CC stable maintainers" bits
- fix a few typos and mistakes in the text, with a few very small
improvements along the way
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/07bca15d8465b8e234537feb8841dd2ff20243bc.1617113469.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Make the TLDR a bit shorter while improving it at the same time by going
straight to the aspects readers are more interested it. The change makes
the process especially more straight-forward for people that hit a
regression in a stable or longterm kernel. Due to the changes the TLDR
now also matches the step by step guide better.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/762ccd7735315d2fdaa79612fccc1f474881118b.1617113469.git.linux@leemhuis.info
[ jc: fixed transposed _` as noted by Thorsten ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Remove the WIP and two FIXME notes in the text to make it official, as
it's now considered fully ready for consumption. To make sure this
step is okay for people the intent of this change and the latest version
of the text were posted to ksummit-discuss; nobody complained, thus
lets move ahead.
Add a footer to point out people can contact Thorsten directly in case
they find something to improve in the text.
Dear reporting-bugs.rst, I'm sorry to tell you, but that makes you fully
obsolete and we thus have to let you go now. Thank you very much for
your service, you in one form or another have been around for a long
time. I'm sure over the years you got read a lot and helped quite a few
people. But it's time to retire now. Rest in peace.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Harry Wei <harryxiyou@gmail.com>
CC: Alex Shi <alex.shi@linux.alibaba.com>
CC: Federico Vaga <federico.vaga@vaga.pv.it>
CC: Greg KH <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/49c674c2d304d87e6259063580fda05267e8c348.1617113469.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
There could be a scenario where we define some region
in normal memory and use them store to logs which is later
retrieved by bootloader during warm reset.
In this scenario, we wanted to treat this memory as normal
cacheable memory instead of default behaviour which
is an overhead. Making it cacheable could improve
performance.
This commit gives control to change mem_type from Device
tree, and also documents the value for normal memory.
Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/1616438537-13719-1-git-send-email-mojha@codeaurora.org
First of all one of the parameter missed 'mockup' in its name,
Second, the semantics of the integer pairs depends on the sign
of the base (the first value in the pair).
Update documentation to reflect the real code behaviour.
Fixes: 2fd1abe99e ("Documentation: gpio: add documentation for gpio-mockup")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
netdev_unregister_timeout_secs=0 can lead to printing the
"waiting for dev to become free" message every jiffy.
This is too frequent and unnecessary.
Set the min value to 1 second.
Also fix the merge issue introduced by
"net: make unregister netdev warning timeout configurable":
it changed "refcnt != 1" to "refcnt".
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Fixes: 5aa3afe107 ("net: make unregister netdev warning timeout configurable")
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we're about to start using the blockgc workqueue to dispose of
inactivated inodes, strip the "block" prefix from the name; now it's
merely the general garbage collection (gc) workqueue.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Provide a shorter and easier process for users that deal with
regressions in stable and longterm kernels, as those should be reported
quickly.
To realize this in the least-confusing way and without having steps
multiple times in different places, split the 'search for existing
reports' into two. That has the additinal benefit that users will search
for them quickly when going through the step by step guide and thus will
save them trouble if the find reports.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
CC: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/d934c15e536bceeff5c40a126930ddf803548e08.1616181657.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
netdev_wait_allrefs() issues a warning if refcount does not drop to 0
after 10 seconds. While 10 second wait generally should not happen
under normal workload in normal environment, it seems to fire falsely
very often during fuzzing and/or in qemu emulation (~10x slower).
At least it's not possible to understand if it's really a false
positive or not. Automated testing generally bumps all timeouts
to very high values to avoid flake failures.
Add net.core.netdev_unregister_timeout_secs sysctl to make
the timeout configurable for automated testing systems.
Lowering the timeout may also be useful for e.g. manual bisection.
The default value matches the current behavior.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=211877
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
In converting intel-iommu over to the common IOMMU DMA ops, it quietly
lost the functionality of its "forcedac" option. Since this is a handy
thing both for testing and for performance optimisation on certain
platforms, reimplement it under the common IOMMU parameter namespace.
For the sake of fixing the inadvertent breakage of the Intel-specific
parameter, remove the dmar_forcedac remnants and hook it up as an alias
while documenting the transition to the new common parameter.
Fixes: c588072bba ("iommu/vt-d: Convert intel iommu driver to the iommu ops")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/7eece8e0ea7bfbe2cd0e30789e0d46df573af9b0.1614961776.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Loadpin cmdline interface "enabled" has been renamed to "enforce"
for a long time, but the User Description Document was not updated.
(Meaning unchanged)
And kernel_read_file* were moved from linux/fs.h to its own
linux/kernel_read_file.h include file. So update that change here.
Signed-off-by: Jiele zhao <unclexiaole@gmail.com>
Link: https://lore.kernel.org/r/20210308020358.102836-1-unclexiaole@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The Cyclades driver was orphaned by commit d459883e6c (MAINTAINERS:
remove two dead e-mail) 13 years ago. Noone stepped up to take care of
them and to fix all the issues the driver has.
On the top of that, there is no way to obtain the firmware for Z cards
from the vendor as cyclades.com ceased to exist.
So it's time to drop the driver with all its traces.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The riscv [rv32_]defconfig enabled CONFIG_MEMTEST,
but memtest feature is not supported in RISCV.
Add early_memtest() to support for memtest.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
The single-argument variant of kfree_rcu() is currently not
tested by any member of the rcutoture test suite. This
commit therefore adds rcuscale code to test it. This
testing is controlled by two new boolean module parameters,
kfree_rcu_test_single and kfree_rcu_test_double. If one
is set and the other not, only the corresponding variant
is tested, otherwise both are tested, with the variant to
be tested determined randomly on each invocation.
Both of these module parameters are initialized to false,
so setting either to true will test only that variant.
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
With the core bitmap support now accepting "N" as a placeholder for
the end of the bitmap, "all" can be represented as "0-N" and has the
advantage of not being specific to RCU (or any other subsystem).
So deprecate the use of "all" by removing documentation references
to it. The support itself needs to remain for now, since we don't
know how many people out there are using it currently, but since it
is in an __init area anyway, it isn't worth losing sleep over.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
While this is done for all bitmaps, the original use case in mind was
for CPU masks and cpulist_parse() as described below.
It seems that a common configuration is to use the 1st couple cores for
housekeeping tasks. This tends to leave the remaining ones to form a
pool of similarly configured cores to take on the real workload of
interest to the user.
So on machine A - with 32 cores, it could be 0-3 for "system" and then
4-31 being used in boot args like nohz_full=, or rcu_nocbs= as part of
setting up the worker pool of CPUs.
But then newer machine B is added, and it has 48 cores, and so while
the 0-3 part remains unchanged, the pool setup cpu list becomes 4-47.
Multiple deployment becomes easier when we can just simply replace 31
and 47 with "N" and let the system substitute in the actual number at
boot; a number that it knows better than we do.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Yury Norov <yury.norov@gmail.com> # move it from CPU code
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
After dropping all of the code using ACPI_PCI_COMPONENT drop the
definition of it too and update the documentation to remove all
ACPI_PCI_COMPONENT references from it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Replace placeholder text about decoding stack traces with a section that
properly describes what a typical user should do these days. To make
it works for them, add a paragraph in an earlier section to ensure
people build their kernels with everything that's needed to decode stack
traces later.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Qais Yousef <qais.yousef@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20210215172857.382285-1-linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
In order to help identifying problems with IPI handling and remote
function execution add some more data to IPI debugging code.
There have been multiple reports of CPUs looping long times (many
seconds) in smp_call_function_many() waiting for another CPU executing
a function like tlb flushing. Most of these reports have been for
cases where the kernel was running as a guest on top of KVM or Xen
(there are rumours of that happening under VMWare, too, and even on
bare metal).
Finding the root cause hasn't been successful yet, even after more than
2 years of chasing this bug by different developers.
Commit:
35feb60474 ("kernel/smp: Provide CSD lock timeout diagnostics")
tried to address this by adding some debug code and by issuing another
IPI when a hang was detected. This helped mitigating the problem
(the repeated IPI unlocks the hang), but the root cause is still unknown.
Current available data suggests that either an IPI wasn't sent when it
should have been, or that the IPI didn't result in the target CPU
executing the queued function (due to the IPI not reaching the CPU,
the IPI handler not being called, or the handler not seeing the queued
request).
Try to add more diagnostic data by introducing a global atomic counter
which is being incremented when doing critical operations (before and
after queueing a new request, when sending an IPI, and when dequeueing
a request). The counter value is stored in percpu variables which can
be printed out when a hang is detected.
The data of the last event (consisting of sequence counter, source
CPU, target CPU, and event type) is stored in a global variable. When
a new event is to be traced, the data of the last event is stored in
the event related percpu location and the global data is updated with
the new event's data. This allows to track two events in one data
location: one by the value of the event data (the event before the
current one), and one by the location itself (the current event).
A typical printout with a detected hang will look like this:
csd: Detected non-responsive CSD lock (#1) on CPU#1, waiting 5000000003 ns for CPU#06 scf_handler_1+0x0/0x50(0xffffa2a881bb1410).
csd: CSD lock (#1) handling prior scf_handler_1+0x0/0x50(0xffffa2a8813823c0) request.
csd: cnt(00008cc): ffff->0000 dequeue (src cpu 0 == empty)
csd: cnt(00008cd): ffff->0006 idle
csd: cnt(0003668): 0001->0006 queue
csd: cnt(0003669): 0001->0006 ipi
csd: cnt(0003e0f): 0007->000a queue
csd: cnt(0003e10): 0001->ffff ping
csd: cnt(0003e71): 0003->0000 ping
csd: cnt(0003e72): ffff->0006 gotipi
csd: cnt(0003e73): ffff->0006 handle
csd: cnt(0003e74): ffff->0006 dequeue (src cpu 0 == empty)
csd: cnt(0003e7f): 0004->0006 ping
csd: cnt(0003e80): 0001->ffff pinged
csd: cnt(0003eb2): 0005->0001 noipi
csd: cnt(0003eb3): 0001->0006 queue
csd: cnt(0003eb4): 0001->0006 noipi
csd: cnt now: 0003f00
The idea is to print only relevant entries. Those are all events which
are associated with the hang (so sender side events for the source CPU
of the hanging request, and receiver side events for the target CPU),
and the related events just before those (for adding data needed to
identify a possible race). Printing all available data would be
possible, but this would add large amounts of data printed on larger
configurations.
Signed-off-by: Juergen Gross <jgross@suse.com>
[ Minor readability edits. Breaks col80 but is far more readable. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20210301101336.7797-4-jgross@suse.com
Currently CSD lock debugging can be switched on and off via a kernel
config option only. Unfortunately there is at least one problem with
CSD lock handling pending for about 2 years now, which has been seen
in different environments (mostly when running virtualized under KVM
or Xen, at least once on bare metal). Multiple attempts to catch this
issue have finally led to introduction of CSD lock debug code, but
this code is not in use in most distros as it has some impact on
performance.
In order to be able to ship kernels with CONFIG_CSD_LOCK_WAIT_DEBUG
enabled even for production use, add a boot parameter for switching
the debug functionality on. This will reduce any performance impact
of the debug coding to a bare minimum when not being used.
Signed-off-by: Juergen Gross <jgross@suse.com>
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210301101336.7797-2-jgross@suse.com
Pull more xfs updates from Darrick Wong:
"The most notable fix here prevents premature reuse of freed metadata
blocks, and adding the ability to detect accidental nested
transactions, which are not allowed here.
- Restore a disused sysctl control knob that was inadvertently
dropped during the merge window to avoid fstests regressions.
- Don't speculatively release freed blocks from the busy list until
we're actually allocating them, which fixes a rare log recovery
regression.
- Don't nest transactions when scanning for free space.
- Add an idiot^Wmaintainer light to detect nested transactions. ;)"
* tag 'xfs-5.12-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: use current->journal_info for detecting transaction recursion
xfs: don't nest transactions when scanning for eofblocks
xfs: don't reuse busy extents on extent trim
xfs: restore speculative_cow_prealloc_lifetime sysctl
Pull documentation fixes from Jonathan Corbet:
"A handful of late-arriving documentation fixes, nothing all that
notable"
* tag 'docs-5.12-2' of git://git.lwn.net/linux:
docs: proc.rst: fix indentation warning
Documentation: cgroup-v2: fix path to example BPF program
docs: powerpc: Fix tables in syscall64-abi.rst
Documentation: features: refresh feature list
Documentation: features: remove c6x references
docs: ABI: testing: ima_policy: Fixed missing bracket
Fix unaesthetic indentation
scripts: kernel-doc: fix array element capture in pointer-to-func parsing
doc: use KCFLAGS instead of EXTRA_CFLAGS to pass flags from command line
Documentation: proc.rst: add more about the 6 fields in loadavg
Pull cifs updates from Steve French:
- improvements to mode bit conversion, chmod and chown when using
cifsacl mount option
- two new mount options for controlling attribute caching
- improvements to crediting and reconnect, improved debugging
- reconnect fix
- add SMB3.1.1 dialect to default dialects for vers=3
* tag '5.12-smb3-part1' of git://git.samba.org/sfrench/cifs-2.6: (27 commits)
cifs: update internal version number
cifs: use discard iterator to discard unneeded network data more efficiently
cifs: introduce helper for finding referral server to improve DFS target resolution
cifs: check all path components in resolved dfs target
cifs: fix DFS failover
cifs: fix nodfs mount option
cifs: fix handling of escaped ',' in the password mount argument
cifs: Add new parameter "acregmax" for distinct file and directory metadata timeout
cifs: convert revalidate of directories to using directory metadata cache timeout
cifs: Add new mount parameter "acdirmax" to allow caching directory metadata
cifs: If a corrupted DACL is returned by the server, bail out.
cifs: minor simplification to smb2_is_network_name_deleted
TCON Reconnect during STATUS_NETWORK_NAME_DELETED
cifs: cleanup a few le16 vs. le32 uses in cifsacl.c
cifs: Change SIDs in ACEs while transferring file ownership.
cifs: Retain old ACEs when converting between mode bits and ACL.
cifs: Fix cifsacl ACE mask for group and others.
cifs: clarify hostname vs ip address in /proc/fs/cifs/DebugData
cifs: change confusing field serverName (to ip_addr)
cifs: Fix inconsistent IS_ERR and PTR_ERR
...
Add a kernel parameter stack_depot_disable to disable stack depot. So
that stack hash table doesn't consume any memory when stack depot is
disabled.
The use case is CONFIG_PAGE_OWNER without page_owner=on. Without this
patch, stackdepot will consume the memory for the hashtable. By default,
it's 8M which is never trivial.
With this option, in CONFIG_PAGE_OWNER configured system, page_owner=off,
stack_depot_disable in kernel command line, we could save the wasted
memory for the hashtable.
[akpm@linux-foundation.org: fix CONFIG_STACKDEPOT=n build]
Link: https://lkml.kernel.org/r/1611749198-24316-2-git-send-email-vjitta@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yogesh Lal <ylal@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No need to store the value for each and every memory block, as we can
easily query the value at runtime. Reshuffle the members to optimize the
memory layout. Also, let's clarify what the interface once was used for
and why it's legacy nowadays.
"phys_device" was used on s390x in older versions of lsmem[2]/chmem[3],
back when they were still part of s390x-tools. They were later replaced
by the variants in linux-utils. For example, RHEL6 and RHEL7 contain
lsmem/chmem from s390-utils. RHEL8 switched to versions from util-linux
on s390x [4].
"phys_device" was added with sysfs support for memory hotplug in commit
3947be1969 ("[PATCH] memory hotplug: sysfs and add/remove functions") in
2005. It always returned 0.
s390x started returning something != 0 on some setups (if sclp.rzm is set
by HW) in 2010 via commit 57b552ba0b ("memory hotplug/s390: set
phys_device").
For s390x, it allowed for identifying which memory block devices belong to
the same storage increment (RZM). Only if all memory block devices
comprising a single storage increment were offline, the memory could
actually be removed in the hypervisor.
Since commit e5d709bb5f ("s390/memory hotplug: provide
memory_block_size_bytes() function") in 2013 a memory block device spans
at least one storage increment - which is why the interface isn't really
helpful/used anymore (except by old lsmem/chmem tools).
There were once RFC patches to make use of "phys_device" in ACPI context;
however, the underlying problem could be solved using different interfaces
[1].
[1] https://patchwork.kernel.org/patch/2163871/
[2] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/lsmem
[3] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/chmem
[4] https://bugzilla.redhat.com/show_bug.cgi?id=1504134
Link: https://lkml.kernel.org/r/20210201181347.13262-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Tom Rix <trix@redhat.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
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 small subsystems and some of MM.
172 patches.
Subsystems affected by this patch series: hexagon, scripts, ntfs,
ocfs2, vfs, and mm (slab-generic, slab, slub, debug, pagecache, swap,
memcg, pagemap, mprotect, mremap, page-reporting, vmalloc, kasan,
pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
mempolicy, oom-kill, hugetlbfs, and migration)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (172 commits)
mm/migrate: remove unneeded semicolons
hugetlbfs: remove unneeded return value of hugetlb_vmtruncate()
hugetlbfs: fix some comment typos
hugetlbfs: correct some obsolete comments about inode i_mutex
hugetlbfs: make hugepage size conversion more readable
hugetlbfs: remove meaningless variable avoid_reserve
hugetlbfs: correct obsolete function name in hugetlbfs_read_iter()
hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fs
hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr()
hugetlbfs: remove special hugetlbfs_set_page_dirty()
mm/hugetlb: change hugetlb_reserve_pages() to type bool
mm, oom: fix a comment in dump_task()
mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk()
numa balancing: migrate on fault among multiple bound nodes
mm, compaction: make fast_isolate_freepages() stay within zone
mm/compaction: fix misbehaviors of fast_find_migrateblock()
mm/compaction: correct deferral logic for proactive compaction
mm/compaction: remove duplicated VM_BUG_ON_PAGE !PageLocked
mm/compaction: remove rcu_read_lock during page compaction
z3fold: simplify the zhdr initialization code in init_z3fold_page()
...
I went to go add a new RECLAIM_* mode for the zone_reclaim_mode sysctl.
Like a good kernel developer, I also went to go update the
documentation. I noticed that the bits in the documentation didn't
match the bits in the #defines.
The VM never explicitly checks the RECLAIM_ZONE bit. The bit is,
however implicitly checked when checking 'node_reclaim_mode==0'. The
RECLAIM_ZONE #define was removed in a cleanup. That, by itself is fine.
But, when the bit was removed (bit 0) the _other_ bit locations also got
changed. That's not OK because the bit values are documented to mean
one specific thing. Users surely do not expect the meaning to change
from kernel to kernel.
The end result is that if someone had a script that did:
sysctl vm.zone_reclaim_mode=1
it would have gone from enabling node reclaim for clean unmapped pages
to writing out pages during node reclaim after the commit in question.
That's not great.
Put the bits back the way they were and add a comment so something like
this is a bit harder to do again. Update the documentation to make it
clear that the first bit is ignored.
Link: https://lkml.kernel.org/r/20210219172555.FF0CDF23@viggo.jf.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Fixes: 648b5cf368 ("mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE")
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds swapcache stat for the cgroup v2. The swapcache
represents the memory that is accounted against both the memory and the
swap limit of the cgroup. The main motivation behind exposing the
swapcache stat is for enabling users to gracefully migrate from cgroup
v1's memsw counter to cgroup v2's memory and swap counters.
Cgroup v1's memsw limit allows users to limit the memory+swap usage of a
workload but without control on the exact proportion of memory and swap.
Cgroup v2 provides separate limits for memory and swap which enables more
control on the exact usage of memory and swap individually for the
workload.
With some little subtleties, the v1's memsw limit can be switched with the
sum of the v2's memory and swap limits. However the alternative for memsw
usage is not yet available in cgroup v2. Exposing per-cgroup swapcache
stat enables that alternative. Adding the memory usage and swap usage and
subtracting the swapcache will approximate the memsw usage. This will
help in the transparent migration of the workloads depending on memsw
usage and limit to v2' memory and swap counters.
The reasons these applications are still interested in this approximate
memsw usage are: (1) these applications are not really interested in two
separate memory and swap usage metrics. A single usage metric is more
simple to use and reason about for them.
(2) The memsw usage metric hides the underlying system's swap setup from
the applications. Applications with multiple instances running in a
datacenter with heterogeneous systems (some have swap and some don't) will
keep seeing a consistent view of their usage.
[akpm@linux-foundation.org: fix CONFIG_SWAP=n build]
Link: https://lkml.kernel.org/r/20210108155813.2914586-3-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Simple Firmware Interface (SFI) support removal from Rafael Wysocki:
"Drop support for depercated platforms using SFI, drop the entire
support for SFI that has been long deprecated too and make some
janitorial changes on top of that (Andy Shevchenko)"
* tag 'sfi-removal-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
x86/platform/intel-mid: Update Copyright year and drop file names
x86/platform/intel-mid: Remove unused header inclusion in intel-mid.h
x86/platform/intel-mid: Drop unused __intel_mid_cpu_chip and Co.
x86/platform/intel-mid: Get rid of intel_scu_ipc_legacy.h
x86/PCI: Describe @reg for type1_access_ok()
x86/PCI: Get rid of custom x86 model comparison
sfi: Remove framework for deprecated firmware
cpufreq: sfi-cpufreq: Remove driver for deprecated firmware
media: atomisp: Remove unused header
mfd: intel_msic: Remove driver for deprecated platform
x86/apb_timer: Remove driver for deprecated platform
x86/platform/intel-mid: Remove unused leftovers (vRTC)
x86/platform/intel-mid: Remove unused leftovers (msic)
x86/platform/intel-mid: Remove unused leftovers (msic_thermal)
x86/platform/intel-mid: Remove unused leftovers (msic_power_btn)
x86/platform/intel-mid: Remove unused leftovers (msic_gpio)
x86/platform/intel-mid: Remove unused leftovers (msic_battery)
x86/platform/intel-mid: Remove unused leftovers (msic_ocd)
x86/platform/intel-mid: Remove unused leftovers (msic_audio)
platform/x86: intel_scu_wdt: Drop mistakenly added const
