| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
The affected CPU table (cpu_vuln_blacklist) marks Alderlake and Raptorlake
P-only parts affected by RFDS. This is not true because only E-cores are
affected by RFDS. With the current family/model matching it is not possible
to differentiate the unaffected parts, as the affected and unaffected
hybrid variants have the same model number.
Add a cpu-type match as well for such parts so as to exclude P-only parts
being marked as affected.
Note, family/model and cpu-type enumeration could be inaccurate in
virtualized environments. In a guest affected status is decided by RFDS_NO
and RFDS_CLEAR bits exposed by VMMs.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-5-e8514dcaaff2@linux.intel.com
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
The page allocator groups requests by migratetype to stave off
fragmentation. However, in practice this is routinely defeated by the
fact that it gives up *before* invoking reclaim and compaction - which may
well produce suitable pages. As a result, fragmentation of physical
memory is a common ongoing process in many load scenarios.
Fragmentation deteriorates compaction's ability to produce huge pages.
Depending on the lifetime of the fragmenting allocations, those effects
can be long-lasting or even permanent, requiring drastic measures like
forcible idle states or even reboots as the only reliable ways to recover
the address space for THP production.
In a kernel build test with supplemental THP pressure, the THP allocation
rate steadily declines over 15 runs:
thp_fault_alloc
61988
56474
57258
50187
52388
55409
52925
47648
43669
40621
36077
41721
36685
34641
33215
This is a hurdle in adopting THP in any environment where hosts are shared
between multiple overlapping workloads (cloud environments), and rarely
experience true idle periods. To make THP a reliable and predictable
optimization, there needs to be a stronger guarantee to avoid such
fragmentation.
Introduce defrag_mode. When enabled, reclaim/compaction is invoked to its
full extent *before* falling back. Specifically, ALLOC_NOFRAGMENT is
enforced on the allocator fastpath and the reclaiming slowpath.
For now, fallbacks are permitted to avert OOMs. There is a plan to add
defrag_mode=2 to prefer OOMs over fragmentation, but this requires
additional prep work in compaction and the reserve management to make it
ready for all possible allocation contexts.
The following test results are from a kernel build with periodic bursts of
THP allocations, over 15 runs:
vanilla defrag_mode=1
@claimer[unmovable]: 189 103
@claimer[movable]: 92 103
@claimer[reclaimable]: 207 61
@pollute[unmovable from movable]: 25 0
@pollute[unmovable from reclaimable]: 28 0
@pollute[movable from unmovable]: 38835 0
@pollute[movable from reclaimable]: 147136 0
@pollute[reclaimable from unmovable]: 178 0
@pollute[reclaimable from movable]: 33 0
@steal[unmovable from movable]: 11 0
@steal[unmovable from reclaimable]: 5 0
@steal[reclaimable from unmovable]: 107 0
@steal[reclaimable from movable]: 90 0
@steal[movable from reclaimable]: 354 0
@steal[movable from unmovable]: 130 0
Both types of polluting fallbacks are eliminated in this workload.
Interestingly, whole block conversions are reduced as well. This is
because once a block is claimed for a type, its empty space remains
available for future allocations, instead of being padded with fallbacks;
this allows the native type to group up instead of spreading out to new
blocks. The assumption in the allocator has been that pollution from
movable allocations is less harmful than from other types, since they can
be reclaimed or migrated out should the space be needed. However, since
fallbacks occur *before* reclaim/compaction is invoked, movable pollution
will still cause non-movable allocations to spread out and claim more
blocks.
Without fragmentation, THP rates hold steady with defrag_mode=1:
thp_fault_alloc
32478
20725
45045
32130
14018
21711
40791
29134
34458
45381
28305
17265
22584
28454
30850
While the downward trend is eliminated, the keen reader will of course
notice that the baseline rate is much smaller than the vanilla kernel's to
begin with. This is due to deficiencies in how reclaim and compaction are
currently driven: ALLOC_NOFRAGMENT increases the extent to which smaller
allocations are competing with THPs for pageblocks, while making no effort
themselves to reclaim or compact beyond their own request size. This
effect already exists with the current usage of ALLOC_NOFRAGMENT, but is
amplified by defrag_mode insisting on whole block stealing much more
strongly.
Subsequent patches will address defrag_mode reclaim strategy to raise the
THP success baseline above the vanilla kernel.
Link: https://lkml.kernel.org/r/20250313210647.1314586-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Document {core,ops}_filters directories on usage document.
Link: https://lkml.kernel.org/r/20250305222733.59089-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
(CONFIG_NO_PAGE_MAPCOUNT)
Everything is in place to stop using the per-page mapcounts in large
folios: the mapcount of tail pages will always be logically 0 (-1 value),
just like it currently is for hugetlb folios already, and the page
mapcount of the head page is either 0 (-1 value) or contains a page type
(e.g., hugetlb).
Maintaining _nr_pages_mapped without per-page mapcounts is impossible, so
that one also has to go with CONFIG_NO_PAGE_MAPCOUNT.
There are two remaining implications:
(1) Per-node, per-cgroup and per-lruvec stats of "NR_ANON_MAPPED"
("mapped anonymous memory") and "NR_FILE_MAPPED"
("mapped file memory"):
As soon as any page of the folio is mapped -- folio_mapped() -- we
now account the complete folio as mapped. Once the last page is
unmapped -- !folio_mapped() -- we account the complete folio as
unmapped.
This implies that ...
* "AnonPages" and "Mapped" in /proc/meminfo and
/sys/devices/system/node/*/meminfo
* cgroup v2: "anon" and "file_mapped" in "memory.stat" and
"memory.numa_stat"
* cgroup v1: "rss" and "mapped_file" in "memory.stat" and
"memory.numa_stat
... can now appear higher than before. But note that these folios do
consume that memory, simply not all pages are actually currently
mapped.
It's worth nothing that other accounting in the kernel (esp. cgroup
charging on allocation) is not affected by this change.
[why oh why is "anon" called "rss" in cgroup v1]
(2) Detecting partial mappings
Detecting whether anon THPs are partially mapped gets a bit more
unreliable. As long as a single MM maps such a large folio
("exclusively mapped"), we can reliably detect it. Especially before
fork() / after a short-lived child process quit, we will detect
partial mappings reliably, which is the common case.
In essence, if the average per-page mapcount in an anon THP is < 1,
we know for sure that we have a partial mapping.
However, as soon as multiple MMs are involved, we might miss detecting
partial mappings: this might be relevant with long-lived child
processes. If we have a fully-mapped anon folio before fork(), once
our child processes and our parent all unmap (zap/COW) the same pages
(but not the complete folio), we might not detect the partial mapping.
However, once the child processes quit we would detect the partial
mapping.
How relevant this case is in practice remains to be seen.
Swapout/migration will likely mitigate this.
In the future, RMAP walkers could check for that for that case
(e.g., when collecting access bits during reclaim) and simply flag
them for deferred-splitting.
Link: https://lkml.kernel.org/r/20250303163014.1128035-21-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
PM_MMAP_EXCLUSIVE will now be set if folio_likely_mapped_shared() is true
-- when the folio is considered "mapped shared", including when it once
was "mapped shared" but no longer is, as documented.
This might result in and under-indication of "exclusively mapped", which
is considered better than over-indicating it: under-estimating the USS
(Unique Set Size) is better than over-estimating it.
As an alternative, we could simply remove that flag with
CONFIG_NO_PAGE_MAPCOUNT completely, but there might be value to it. So,
let's keep it like that and document the behavior.
Link: https://lkml.kernel.org/r/20250303163014.1128035-18-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
For large folios, we'll return the per-page average mapcount within the
folio, whereby we round to the closest integer when calculating the
average: however, we'll always return at least 1 if the folio is mapped.
So assuming a folio with 512 pages, the average would be:
* 0 if not pages are mapped
* 1 if there are 1 .. 767 per-page mappings
* 2 if there are 767 .. 1279 per-page mappings
...
For hugetlb folios and for large folios that are fully mapped into all
address spaces, there is no change.
We'll make use of this helper in other context next.
As an alternative, we could simply return 0 for non-hugetlb large folios,
or disable this legacy interface with CONFIG_NO_PAGE_MAPCOUNT.
But the information exposed by this interface can still be valuable, and
frequently we deal with fully-mapped large folios where the average
corresponds to the actual page mapcount. So we'll leave it like this for
now and document the new behavior.
Note: this interface is likely not very relevant for performance. If ever
required, we could try doing a rather expensive rmap walk to collect
precisely how often this folio page is mapped.
Link: https://lkml.kernel.org/r/20250303163014.1128035-17-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The highuid.rst document describes a transition that is outdated and no
longer relevant. Additionally, it references filesystems (ncpfs and smbfs),
which have been removed or replaced.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Kang Taeho <kangtaeho2456@gmail.com>
Link: https://lore.kernel.org/r/20250313145650.278346-1-kangtaeho2456@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
|
|
The new option is CONFIG_NULL_TTY_DEFAULT_CONSOLE.
if enabled, and CONFIG_VT is disabled, ttynull will become the default
primary console device.
ttynull will be the only console device usually with this option enabled.
Some architectures do call add_preferred_console() which may add another
console though.
Motivation:
Many distributions ship with CONFIG_VT enabled. On tested desktop hardware
if CONFIG_VT is disabled, the default console device falls back to
/dev/ttyS0 instead of /dev/tty.
This could cause issues in user space, and hardware problems:
1. The user space issues include the case where /dev/ttyS0 is
disconnected, and the TCGETS ioctl, which some user space libraries use
as a probe to determine if a file is a tty, is called on /dev/console and
fails. Programs that call isatty() on /dev/console and get an incorrect
false value may skip expected logging to /dev/console.
2. The hardware issues include the case if a user has a science instrument
or other device connected to the /dev/ttyS0 port, and they were to upgrade
to a kernel that is disabling the CONFIG_VT option, kernel logs will then
be sent to the device connected to /dev/ttyS0 unless they edit their
kernel command line manually.
The new CONFIG_NULL_TTY_DEFAULT_CONSOLE option will give users and
distribution maintainers an option to avoid this. Disabling CONFIG_VT and
enabling CONFIG_NULL_TTY_DEFAULT_CONSOLE will ensure the default kernel
console behavior is not dependent on hardware configuration by default, and
avoid unexpected new behavior on devices connected to the /dev/ttyS0 serial
port.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Adam Simonelli <adamsimonelli@gmail.com>
Link: https://lore.kernel.org/r/20250314160749.3286153-2-adamsimonelli@gmail.com
[pmladek@suse.com: Fixed indentation of the commit message.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
|
|
Add a command line option that enables control of how many threads should
be used to allocate huge pages.
[akpm@linux-foundation.org: tidy up a comment]
Link: https://lkml.kernel.org/r/20250227-hugepage-parameter-v2-2-7db8c6dc0453@cyberus-technology.de
Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Document DAMON sysfs interface usage for DAMON sampling and aggregation
intervals auto-tuning.
Link: https://lkml.kernel.org/r/20250303221726.484227-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We currently leave the decision of whether to shutdown or reboot to
protect hardware in an emergency situation to the individual drivers.
This works out in some cases, where the driver detecting the critical
failure has inside knowledge: It binds to the system management controller
for example or is guided by hardware description that defines what to do.
In the general case, however, the driver detecting the issue can't know
what the appropriate course of action is and shouldn't be dictating the
policy of dealing with it.
Therefore, add a global hw_protection toggle that allows the user to
specify whether shutdown or reboot should be the default action when the
driver doesn't set policy.
This introduces no functional change yet as hw_protection_trigger() has no
callers, but these will be added in subsequent commits.
[arnd@arndb.de: hide unused hw_protection_attr]
Link: https://lkml.kernel.org/r/20250224141849.1546019-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-7-e1c09b090c0c@pengutronix.de
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Cc: Benson Leung <bleung@chromium.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matteo Croce <teknoraver@meta.com>
Cc: Matti Vaittinen <mazziesaccount@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rob Herring (Arm) <robh@kernel.org>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "fs/proc/task_mmu: add guard region bit to pagemap".
Currently there is no means of determining whether a given page in a
mapping range is designated a guard region (as installed via madvise()
using the MADV_GUARD_INSTALL flag).
This is generally not an issue, but in some instances users may wish to
determine whether this is the case.
This series adds this ability via /proc/$pid/pagemap, updates the
documentation and adds a self test to assert that this functions
correctly.
This patch (of 2):
Currently there is no means by which users can determine whether a given
page in memory is in fact a guard region, that is having had the
MADV_GUARD_INSTALL madvise() flag applied to it.
This is intentional, as to provide this information in VMA metadata would
contradict the intent of the feature (providing a means to change fault
behaviour at a page table level rather than a VMA level), and would
require VMA metadata operations to scan page tables, which is
unacceptable.
In many cases, users have no need to reflect and determine what regions
have been designated guard regions, as it is the user who has established
them in the first place.
But in some instances, such as monitoring software, or software that
relies upon being able to ascertain the nature of mappings within a remote
process for instance, it becomes useful to be able to determine which
pages have the guard region marker applied.
This patch makes use of an unused pagemap bit (58) to provide this
information.
This patch updates the documentation at the same time as making the change
such that the implementation of the feature and the documentation of it
are tied together.
Link: https://lkml.kernel.org/r/cover.1740139449.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/521d99c08b975fb06a1e7201e971cc24d68196d1.1740139449.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
max_comp_streams device attribute has been defunct since May 2016 when
zram switched to per-CPU compression streams, remove it.
Link: https://lkml.kernel.org/r/20250303022425.285971-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add an option to force hugetlb gigantic pages to be allocated using CMA
only (if hugetlb_cma is enabled). This avoids a fallback to allocation
from the rest of system memory if the CMA allocation fails. This makes
the size of hugetlb_cma a hard upper boundary for gigantic hugetlb page
allocations.
This is useful because, with a large CMA area, the kernel's unmovable
allocations will have less room to work with and it is undesirable for new
hugetlb gigantic page allocations to be done from that remaining area. It
will eat in to the space available for unmovable allocations, leading to
unwanted system behavior (OOMs because the kernel fails to do unmovable
allocations).
So, with this enabled, an administrator can force a hard upper bound for
runtime gigantic page allocations, and have more predictable system
behavior.
Link: https://lkml.kernel.org/r/20250228182928.2645936-26-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Convert the cmdline parameters (hugepagesz, hugepages, default_hugepagesz
and hugetlb_free_vmemmap) to early parameters.
Since parse_early_param might run before MMU setups on some platforms
(powerpc), validation of huge page sizes as specified in command line
parameters would fail. So instead, for the hstate-related values, just
record the them and parse them on demand, from hugetlb_bootmem_alloc.
The allocation of hugetlb bootmem pages is now done in
hugetlb_bootmem_alloc, which is called explicitly at the start of
mm_core_init(). core_initcall would be too late, as that happens with
memblock already torn down.
This change will allow earlier allocation and initialization of bootmem
hugetlb pages later on.
No functional change intended.
Link: https://lkml.kernel.org/r/20250228182928.2645936-8-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently, CMA manages one range of physically contiguous memory.
Creation of larger CMA areas with hugetlb_cma may run in to gaps in
physical memory, so that they are not able to allocate that contiguous
physical range from memblock when creating the CMA area.
This can happen, for example, on an AMD system with > 1TB of memory, where
there will be a gap just below the 1TB (40bit DMA) line. If you have set
aside most of memory for potential hugetlb CMA allocation,
cma_declare_contiguous_nid will fail.
hugetlb_cma doesn't need the entire area to be one physically contiguous
range. It just cares about being able to get physically contiguous chunks
of a certain size (e.g. 1G), and it is fine to have the CMA area backed
by multiple physical ranges, as long as it gets 1G contiguous allocations.
Multi-range support is implemented by introducing an array of ranges,
instead of just one big one. Each range has its own bitmap. Effectively,
the allocate and release operations work as before, just per-range. So,
instead of going through one large bitmap, they now go through a number of
smaller ones.
The maximum number of supported ranges is 8, as defined in CMA_MAX_RANGES.
Since some current users of CMA expect a CMA area to just use one
physically contiguous range, only allow for multiple ranges if a new
interface, cma_declare_contiguous_nid_multi, is used. The other
interfaces will work like before, creating only CMA areas with 1 range.
cma_declare_contiguous_nid_multi works as follows, mimicking the
default "bottom-up, above 4G" reservation approach:
0) Try cma_declare_contiguous_nid, which will use only one
region. If this succeeds, return. This makes sure that for
all the cases that currently work, the behavior remains
unchanged even if the caller switches from
cma_declare_contiguous_nid to cma_declare_contiguous_nid_multi.
1) Select the largest free memblock ranges above 4G, with
a maximum number of CMA_MAX_RANGES.
2) If we did not find at most CMA_MAX_RANGES that add
up to the total size requested, return -ENOMEM.
3) Sort the selected ranges by base address.
4) Reserve them bottom-up until we get what we wanted.
Link: https://lkml.kernel.org/r/20250228182928.2645936-3-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
DAMON sysfs usage doc is describing DAMOS filter type names and their
meanings in short. The design doc is providing the short meaning and
detailed descriptions, too. This is unnecessary duplicates and confuses
where to document new DAMOS filter types and features. Move the details
from usage to design doc.
Link: https://lkml.kernel.org/r/20250218223708.53437-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This includes both the 'hugepage_size' filter type and the min/max files
used to decide range of sizes to filter on.
Link: https://lkml.kernel.org/r/20250211124437.278873-5-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The zbud compressed pages allocator is rarely used, most users use
zsmalloc. zbud consumes much more memory (only stores 1 or 2 compressed
pages per physical page). The only advantage of zbud is a marginal
performance improvement that by no means justify the memory overhead.
Historically, zsmalloc had significantly worse latency than zbud and
z3fold but offered better memory savings. This is no longer the case as
shown by a simple recent analysis [1]. In a kernel build test on tmpfs in
a limited cgroup, zbud 2-3% less time than zsmalloc, but at the cost of
using ~32% more memory (1.5G vs 1.13G). The tradeoff does not make sense
for zbud in any practical scenario.
The only alleged advantage of zbud is not having the dependency on
CONFIG_MMU, but CONFIG_SWAP already depends on CONFIG_MMU anyway, and zbud
is only used by zswap.
Remove zbud after z3fold's removal, leaving zsmalloc as the one and only
zpool allocator. Leave the removal of the zpool API (and its associated
config options) to a followup cleanup after no more allocators show up.
Deprecating zbud for a few cycles before removing it was initially
proposed [2], like z3fold was marked as deprecated for 2 cycles [3].
However, Johannes rightfully pointed out that the 2 cycles is too short
for most downstream consumers, and z3fold was deprecated first only as a
courtesy anyway.
[1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/
[2]https://lore.kernel.org/lkml/Z5gdnSX5Lv-nfjQL@google.com/
[3]https://lore.kernel.org/lkml/20240904233343.933462-1-yosryahmed@google.com/
Link: https://lkml.kernel.org/r/20250129180633.3501650-3-yosry.ahmed@linux.dev
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We now print error messages in ext4_end_bio() when page writeback
encounters an error. If data_err=abort is set, the journal will also
be aborted in a kworker. This means that we now check all Buffer I/O
in all modes and decide whether to abort the journal based on the
data_err option. Therefore, we remove the ordered mode restriction
in the descriptions of data_err=abort and data_err=ignore.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250122110533.4116662-8-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
|
|
Ammend missing "install" operation keyword after "apt-get", and fix
"build-essentials" to "build-essential".
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250306030708.8133-1-richard120310@gmail.com
|
|
pnp_remove_card() is currently unused, it has been since it was
added in 2003's BKrev: 3e6d3f19XSmESWEZnNEReEJOJW5SOw
pnp_unregister_protocol() is currently unused, it has been since
it was added in 2002's BKrev: 3df0cf6d4FVUKndhbfxjL7pksw5PGA
Remove them, and pnp_remove_card_device() and __pnp_remove_device()
which are now no longer used.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250307214936.74504-1-linux@treblig.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
As explained in the commit 76f969e8948d8 ("cgroup: cgroup v2 freezer"),
the original freezer is imperfect, some users may unwittingly rely on it
when there exists the alternative of v2. Print a message when it happens
and explain that in the docs.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
The concept of per-memcg swappiness has never landed well in memcg for
cgroup v2. Add a message to users who use it on v1 hierarchy.
Decreased swappiness transforms to memory.swap.max=0 whereas
increased swappiness transforms into active memory.reclaim operation.
Link: https://lore.kernel.org/r/1577252208-32419-1-git-send-email-teawater@gmail.com/
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- Use the specified $(LD) when building userprogs with Clang
- Pass the correct target triple when compile-testing UAPI headers
with Clang
- Fix pacman-pkg build error with KBUILD_OUTPUT
* tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT
docs: Kconfig: fix defconfig description
kbuild: hdrcheck: fix cross build with clang
kbuild: userprogs: use correct lld when linking through clang
|
|
Requesting a fwctl scope of access that includes mutating device debug
data will cause the kernel to be tainted. Changing the device operation
through things in the debug scope may cause the device to malfunction in
undefined ways. This should be reflected in the TAINT flags to help any
debuggers understand that something has been done.
Link: https://patch.msgid.link/r/4-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
|
|
controllers
The cgroup v2 cpu controller has a limitation that if
CONFIG_RT_GROUP_SCHED is enabled, the cpu controller can be enabled only
if all the realtime processes are in the root cgroup. The other
controllers have no such restriction. They can be used for the resource
control of realtime processes irrespective of whether
CONFIG_RT_GROUP_SCHED is enabled or not.
Signed-off-by: Shashank Balaji <shashank.mahadasyam@sony.com>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Commit 2a86f6612164 ("kbuild: use KBUILD_DEFCONFIG as the fallback
for DEFCONFIG_LIST") removed arch/$ARCH/defconfig; however,
the document has not been updated to reflect this change yet.
Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Change the default value of spectre v2 in user mode to respect the
CONFIG_MITIGATION_SPECTRE_V2 config option.
Currently, user mode spectre v2 is set to auto
(SPECTRE_V2_USER_CMD_AUTO) by default, even if
CONFIG_MITIGATION_SPECTRE_V2 is disabled.
Set the spectre_v2 value to auto (SPECTRE_V2_USER_CMD_AUTO) if the
Spectre v2 config (CONFIG_MITIGATION_SPECTRE_V2) is enabled, otherwise
set the value to none (SPECTRE_V2_USER_CMD_NONE).
Important to say the command line argument "spectre_v2_user" overwrites
the default value in both cases.
When CONFIG_MITIGATION_SPECTRE_V2 is not set, users have the flexibility
to opt-in for specific mitigations independently. In this scenario,
setting spectre_v2= will not enable spectre_v2_user=, and command line
options spectre_v2_user and spectre_v2 are independent when
CONFIG_MITIGATION_SPECTRE_V2=n.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Kaplan <David.Kaplan@amd.com>
Link: https://lore.kernel.org/r/20241031-x86_bugs_last_v2-v2-2-b7ff1dab840e@debian.org
|
|
HARDENED_USERCOPY defaults to on if enabled at compile time. Allow
hardened_usercopy= default to be set at compile time similar to
init_on_alloc= and init_on_free=. The intent is that hardening
options that can be disabled at runtime can set their default at
build time.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20250123221115.19722-3-mgorman@techsingularity.net
Signed-off-by: Kees Cook <kees@kernel.org>
|
|
With the maximum amount of RAM now 4GB, there is very little point
to still have PTE pages in highmem. Drop this for simplification.
The only other architecture supporting HIGHPTE is 32-bit arm, and
once that feature is removed as well, the highpte logic can be
dropped from common code as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250226213714.4040853-8-arnd@kernel.org
|
|
HIGHMEM64G support was added in linux-2.3.25 to support (then)
high-end Pentium Pro and Pentium III Xeon servers with more than 4GB of
addressing, NUMA and PCI-X slots started appearing.
I have found no evidence of this ever being used in regular dual-socket
servers or consumer devices, all the users seem obsolete these days,
even by i386 standards:
- Support for NUMA servers (NUMA-Q, IBM x440, unisys) was already
removed ten years ago.
- 4+ socket non-NUMA servers based on Intel 450GX/450NX, HP F8 and
ServerWorks ServerSet/GrandChampion could theoretically still work
with 8GB, but these were exceptionally rare even 20 years ago and
would have usually been equipped with than the maximum amount of
RAM.
- Some SKUs of the Celeron D from 2004 had 64-bit mode fused off but
could still work in a Socket 775 mainboard designed for the later
Core 2 Duo and 8GB. Apparently most BIOSes at the time only allowed
64-bit CPUs.
- The rare Xeon LV "Sossaman" came on a few motherboards with
registered DDR2 memory support up to 16GB.
- In the early days of x86-64 hardware, there was sometimes the need
to run a 32-bit kernel to work around bugs in the hardware drivers,
or in the syscall emulation for 32-bit userspace. This likely still
works but there should never be a need for this any more.
PAE mode is still required to get access to the 'NX' bit on Atom
'Pentium M' and 'Core Duo' CPUs.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250226213714.4040853-6-arnd@kernel.org
|
|
The x86-32 kernel used to support multiple platforms with more than eight
logical CPUs, from the 1999-2003 timeframe: Sequent NUMA-Q, IBM Summit,
Unisys ES7000 and HP F8. Support for all except the latter was dropped
back in 2014, leaving only the F8 based DL740 and DL760 G2 machines in
this catery, with up to eight single-core Socket-603 Xeon-MP processors
with hyperthreading.
Like the already removed machines, the HP F8 servers at the time cost
upwards of $100k in typical configurations, but were quickly obsoleted
by their 64-bit Socket-604 cousins and the AMD Opteron.
Earlier servers with up to 8 Pentium Pro or Xeon processors remain
fully supported as they had no hyperthreading. Similarly, the more
common 4-socket Xeon-MP machines with hyperthreading using Intel
or ServerWorks chipsets continue to work without this, and all the
multi-core Xeon processors also run 64-bit kernels.
While the "bigsmp" support can also be used to run on later 64-bit
machines (including VM guests), it seems best to discourage that
and get any remaining users to update their kernels to 64-bit builds
on these. As a side-effect of this, there is also no more need to
support NUMA configurations on 32-bit x86, as all true 32-bit
NUMA platforms are already gone.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250226213714.4040853-3-arnd@kernel.org
|
|
Remove a reference to CBE_CPUFREQ_SPU_GOVERNOR which has been removed.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241218105523.416573-20-mpe@ellerman.id.au
|
|
Add support for
CPUID Fn8000_0021_EAX[31] (SRSO_MSR_FIX). If this bit is 1, it
indicates that software may use MSR BP_CFG[BpSpecReduce] to mitigate
SRSO.
Enable BpSpecReduce to mitigate SRSO across guest/host boundaries.
Switch back to enabling the bit when virtualization is enabled and to
clear the bit when virtualization is disabled because using a MSR slot
would clear the bit when the guest is exited and any training the guest
has done, would potentially influence the host kernel when execution
enters the kernel and hasn't VMRUN the guest yet.
More detail on the public thread in Link below.
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: ht |
