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Update DAMON usage document for the quota goal target_metric file.
[sj@kernel.org: fix a typo on the auto-tuning design reference link]
Link: https://lkml.kernel.org/r/20240221170852.55529-3-sj@kernel.org
Link: https://lkml.kernel.org/r/20240219194431.159606-18-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update DAMON ABI document for the quota goal target_metric file.
Link: https://lkml.kernel.org/r/20240219194431.159606-17-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update DAMON design doc to explain the quota goal self-tuning, which can
be used by setting the goal's metric to metrics that kernel can
self-retrieve.
Link: https://lkml.kernel.org/r/20240219194431.159606-16-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Extend DAMON sysfs interface to support the PSI-based quota auto-tuning by
adding a new file, 'target_metric' under the quota goal directory. Old
users don't get any behavioral changes since the default value of the
metric is 'user input'.
Link: https://lkml.kernel.org/r/20240219194431.159606-15-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Extend DAMOS quota goal metric with system wide memory pressure stall
time. Specifically, the system level 'some' PSI for memory is used. The
target value can be set in microseconds. DAMOS measures the increased
amount of the PSI metric in last quota_reset_interval and use the ratio of
it versus the user-specified target PSI value as the score for the
auto-tuning feedback loop.
Link: https://lkml.kernel.org/r/20240219194431.159606-14-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMOS quota auto-tuning asks users to assess the current tuned quota and
provide the feedback in a manual and repeated way. It allows users
generate the feedback from a source that the kernel cannot access, and
writing a script or a function for doing the manual and repeated feeding
is not a big deal. However, additional works are additional works, and it
could be more efficient if DAMOS could do the fetch itself, especially in
case of DAMON sysfs interface use case, since it can avoid the context
switches between the user-space and the kernel-space, though the overhead
would be only trivial in most cases. Also in many cases, feedbacks could
be made from kernel-accessible sources, such as PSI, CPU usage, etc. Make
the quota goal to support multiple types of metrics including such ones.
Link: https://lkml.kernel.org/r/20240219194431.159606-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMOS quota auto-tuning feature let users to set the goal by providing a
function for getting the current score of the tuned quota. It allows
flexible goal setup, but only simple user-set quota is currently being
used. As a result, the only user of the DAMOS quota auto-tuning is using
a silly void pointer casting based score value passing function. Simplify
the interface and the user code by letting user directly set the target
and the current value.
Link: https://lkml.kernel.org/r/20240219194431.159606-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMOS quota auto-tuning feature supports static signle goal and dynamic
multiple goals via DAMON kernel API, specifically via ->goal and ->goals
fields of damos_quota struct, respectively. All in-tree DAMOS kernel API
users are using only the dynamic multiple goals now. Remove the unsued
static single goal interface.
Link: https://lkml.kernel.org/r/20240219194431.159606-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON sysfs interface implements multiple quota auto-tuning goals on its
level since the DAMOS core logic was supporting only single goal. Now the
core logic supports multiple goals on its level. Update DAMON sysfs
interface to reuse the core logic and drop unnecessary duplicated multiple
goals implementation.
Link: https://lkml.kernel.org/r/20240219194431.159606-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The feedback-driven DAMOS quota auto-tuning feature allows only single
goal to the DAMON kernel API users. The API users could implement
multiple goals for the end-users on their level, and that's what DAMON
sysfs interface is doing. More DAMON kernel API users such as
DAMON_RECLAIM would need to do similar work. To reduce unnecessary future
duplciated efforts, support multiple goals from DAMOS core layer. To make
the support in minimum non-destructive change, keep the old single goal
setup interface, and add multiple goals setup. The single goal will
treated as one of the multiple goals, so old API users are not required to
make any change.
Link: https://lkml.kernel.org/r/20240219194431.159606-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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'struct damos_quota' is not small now. Split out fields for quota goal to
a separate struct for easier reading.
Link: https://lkml.kernel.org/r/20240219194431.159606-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The comments and definition of 'struct damos_quota' lists a few fields for
effective quota generation first, fields for regions prioritization under
the quota, and then remaining fields for effective quota generation.
Readers' should unnecesssarily switch their context in the middle. List
all the fields for the effective quota first, and then fields for the
prioritization for making it easier to read.
Link: https://lkml.kernel.org/r/20240219194431.159606-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update DAMON usage document for the effective quota file of the DAMON
sysfs interface.
Link: https://lkml.kernel.org/r/20240219194431.159606-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update the DAMON ABI doc for the effective_bytes sysfs file and the
kdamond state file input command for updating the content of the file.
Link: https://lkml.kernel.org/r/20240219194431.159606-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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quotas
Implement yet another kdamond 'state' file input command, namely
'update_schemes_effective_quotas'. If it is written, the
'effective_bytes' files of the kdamond will be updated to provide the
current effective size quota of each scheme in bytes.
Link: https://lkml.kernel.org/r/20240219194431.159606-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON sysfs interface allows users to set two types of quotas, namely time
quota and size quota. DAMOS converts time quota to a size quota and use
smaller one among the resulting two size quotas. The resulting effective
size quota can be helpful for debugging and analysis, but not exposed to
the user. The recently added feedback-driven quota auto-tuning is making
it even more mysterious.
Implement a DAMON sysfs interface read-only empty file, namely
'effective_bytes', under the quota goal DAMON sysfs directory. It will be
extended to expose the effective quota to the end user.
Link: https://lkml.kernel.org/r/20240219194431.159606-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/damon: let DAMOS feeds and tame/auto-tune itself".
The Aim-oriented Feedback-driven DAMOS Aggressiveness Auto-tuning
patchset[1] which has merged since commit 9294a037c015 ("mm/damon/core:
implement goal-oriented feedback-driven quota auto-tuning") made the
mechanism and the policy separated. That is, users can set a part of
DAMOS control policies without a deep understanding of the mechanism but
just their demands such as SLA.
However, users are still required to do some additional work of manually
collecting their target metric and feeding it to DAMOS. In the case of
end-users who use DAMON sysfs interface, the context switches between
user-space and kernel-space could also make it inefficient. The overhead
is supposed to be only trivial in common cases, though. Meanwhile, in
simple use cases, the target metric could be common system metrics that
the kernel can efficiently self-retrieve, such as memory pressure stall
time (PSI).
Extend DAMOS quota auto-tuning to support multiple types of metrics
including the DAMOS self-retrievable ones, and add support for memory
pressure stall time metric. Different types of metrics can be supported
in future. The auto-tuning capability is currently supported for only
users of DAMOS kernel API and DAMON sysfs interface. Extend the support
to DAMON_RECLAIM.
Patches Sequence
================
First five patches are for helping debugging and fine-tuning existing
quota control features. The first one (patch 1) exposes the effective
quota that is made with given user inputs to DAMOS kernel API users and
kernel-doc documents. Following four patches implement (patches 1, 2 and
3) and document (patches 4 and 5) a new DAMON sysfs file that exposes the
value.
Following six patches cleanup and simplify the existing DAMOS quota
auto-tuning code by improving layout of comments and data structures
(patches 6 and 7), supporting common use cases, namely multiple goals
(patches 8, 9 and 10), and simplifying the interface (patch 11).
Then six patches for the main purpose of this patchset follow. The first
three changes extend the core logic for various target metrics (patch 12),
implement memory pressure stall time-based target metric support (patch
13), and update DAMON sysfs interface to support the new target metric
(patch 14). Then, documentation updates for the features on design (patch
15), ABI (patch 16), and usage (patch 17) follow.
Last three patches add auto-tuning support on DAMON_RECLAIM. The patches
implement DAMON_RECLAIM parameters for user-feedback driven quota
auto-tuning (patch 18), memory pressure stall time-driven quota
self-tuning (patch 19), and finally update the DAMON_RECLAIM usage
document for the new parameters (patch 20).
[1] https://lore.kernel.org/all/20231130023652.50284-1-sj@kernel.org/
This patch (of 20):
DAMOS allow users to specify the quota as they want in multiple ways
including time quota, size quota, and feedback-based auto-tuning. DAMOS
makes one effective quota out of the inputs and use it at the end.
Knowing the current effective quota helps understanding DAMOS' internal
mechanism and fine-tuning quotas. DAMON kernel API users can get the
information from ->esz field of damos_quota struct, but the field is
marked as private purpose, and not kernel-doc documented. Make it public
and document.
Link: https://lkml.kernel.org/r/20240219194431.159606-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240219194431.159606-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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khugepaged scans the entire address space in the background for each
given mm, looking for opportunities to merge sequences of basic pages
into huge pages. However, when an mm is inserted to the mm_slots list,
and the MMF_DISABLE_THP flag is set later, this scanning process
becomes unnecessary for that mm and can be skipped to avoid redundant
operations, especially in scenarios with a large address space.
On an Intel Core i5 CPU, the time taken by khugepaged to scan the
address space of the process, which has been set with the
MMF_DISABLE_THP flag after being added to the mm_slots list, is as
follows (shorter is better):
VMA Count | Old | New | Change
---------------------------------------
50 | 23us | 9us | -60.9%
100 | 32us | 9us | -71.9%
200 | 44us | 9us | -79.5%
400 | 75us | 9us | -88.0%
800 | 98us | 9us | -90.8%
Once the count of VMAs for the process exceeds page_to_scan, khugepaged
needs to wait for scan_sleep_millisecs ms before scanning the next
process. IMO, unnecessary scans could actually be skipped with a very
inexpensive mm->flags check in this case.
This commit introduces a check before each scanning process to test the
MMF_DISABLE_THP flag for the given mm; if the flag is set, the scanning
process is bypassed, thereby improving the efficiency of khugepaged.
This optimization is not a correctness issue but rather an enhancement
to save expensive checks on each VMA when userspace cannot prctl itself
before spawning into the new process.
On some servers within our company, we deploy a daemon responsible for
monitoring and updating local applications. Some applications prefer
not to use THP, so the daemon calls prctl to disable THP before
fork/exec. Conversely, for other applications, the daemon calls prctl
to enable THP before fork/exec.
Ideally, the daemon should invoke prctl after the fork, but its current
implementation follows the described approach. In the Go standard
library, there is no direct encapsulation of the fork system call;
instead, fork and execve are combined into one through
syscall.ForkExec.
Link: https://lkml.kernel.org/r/20240129054551.57728-1-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add F: lines for memory management and memory cgroup include files.
Link: https://lkml.kernel.org/r/20240208055727.142387-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Nathan reported below building error:
=====
$ curl -LSso .config https://git.alpinelinux.org/aports/plain/community/linux-edge/config-edge.armv7
$ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- olddefconfig all
..
arm-linux-gnueabi-ld: arch/arm/kernel/machine_kexec.o: in function `arch_crash_save_vmcoreinfo':
machine_kexec.c:(.text+0x488): undefined reference to `vmcoreinfo_append_str'
====
On architecutres, like arm, s390, ppc, sh, function
arch_crash_save_vmcoreinfo() is located in machine_kexec.c and it can
only be compiled in when CONFIG_KEXEC_CORE=y.
That's not right because arch_crash_save_vmcoreinfo() is used to export
arch specific vmcoreinfo. CONFIG_VMCORE_INFO is supposed to control its
compiling in. However, CONFIG_VMVCORE_INFO could be independent of
CONFIG_KEXEC_CORE, e.g CONFIG_PROC_KCORE=y will select CONFIG_VMVCORE_INFO.
Or CONFIG_KEXEC/CONFIG_KEXEC_FILE is set while CONFIG_CRASH_DUMP is
not set, it will report linking error.
So, on arm, s390, ppc and sh, move arch_crash_save_vmcoreinfo out to
a new file vmcore_info.c. Let CONFIG_VMCORE_INFO decide if compiling in
arch_crash_save_vmcoreinfo().
[akpm@linux-foundation.org: remove stray newlines at eof]
Link: https://lkml.kernel.org/r/20240129135033.157195-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on loongarch with some adjustments.
Here use IS_ENABLED(CONFIG_CRASH_RESERVE) check to decide if compiling
in the crashkernel reservation code.
Link: https://lkml.kernel.org/r/20240124051254.67105-15-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on arm with some adjustments.
Here use CONFIG_CRASH_RESERVE ifdef to replace CONFIG_KEXEC ifdef.
Link: https://lkml.kernel.org/r/20240124051254.67105-14-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on risc-v with some adjustments.
Here wrap up crash dumping codes with CONFIG_CRASH_DUMP ifdeffery, and
use IS_ENABLED(CONFIG_CRASH_RESERVE) check to decide if compiling
in the crashkernel reservation code.
Link: https://lkml.kernel.org/r/20240124051254.67105-13-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on mips with some adjustments.
Here use IS_ENABLED(CONFIG_CRASH_RESERVE) check to decide if compiling
in the crashkernel reservation code.
Link: https://lkml.kernel.org/r/20240124051254.67105-12-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on SuperH with some adjustments.
Wrap up crash dumping codes with CONFIG_CRASH_DUMP ifdeffery, and use
IS_ENABLED(CONFIG_CRASH_RESERVE) check to decide if compiling in the
crashkernel reservation code.
Link: https://lkml.kernel.org/r/20240124051254.67105-11-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on s390 with some adjustments.
Here wrap up crash dumping codes with CONFIG_CRASH_DUMP ifdeffery.
Link: https://lkml.kernel.org/r/20240124051254.67105-10-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In PowerPC, the crash dumping and kexec reboot share code in
arch_kexec_locate_mem_hole(), in which struct crash_mem is used.
Here enfoce enforce KEXEC and KEXEC_FILE to select CRASH_DUMP for now.
[bhe@redhat.com: fix allnoconfig on ppc]
Link: https://lkml.kernel.org/r/ZbJwMyCpz4HDySoo@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20240124051254.67105-9-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on arm64 with some adjustments.
Here wrap up crash dumping codes with CONFIG_CRASH_DUMP ifdeffery.
[bhe@redhat.com: fix building error in generic codes]
Link: https://lkml.kernel.org/r/20240129135033.157195-2-bhe@redhat.com
Link: https://lkml.kernel.org/r/20240124051254.67105-8-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now crash codes under kernel/ folder has been split out from kexec
code, crash dumping can be separated from kexec reboot in config
items on x86 with some adjustments.
Here, also change some ifdefs or IS_ENABLED() check to more appropriate
ones, e,g
- #ifdef CONFIG_KEXEC_CORE -> #ifdef CONFIG_CRASH_DUMP
- (!IS_ENABLED(CONFIG_KEXEC_CORE)) - > (!IS_ENABLED(CONFIG_CRASH_RESERVE))
[bhe@redhat.com: don't nest CONFIG_CRASH_DUMP ifdef inside CONFIG_KEXEC_CODE ifdef scope]
Link: https://lore.kernel.org/all/SN6PR02MB4157931105FA68D72E3D3DB8D47B2@SN6PR02MB4157.namprd02.prod.outlook.com/T/#u
Link: https://lkml.kernel.org/r/20240124051254.67105-7-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
By splitting CRASH_RESERVE and VMCORE_INFO out from CRASH_CORE, cleaning
up the dependency of FA_DMUMP on CRASH_DUMP, and moving crash codes from
kexec_core.c to crash_core.c, now we can rearrange CRASH_DUMP to
depend on KEXEC_CORE, and make CRASH_DUMP select CRASH_RESERVE and
VMCORE_INFO.
KEXEC_CORE won't select CRASH_RESERVE and VMCORE_INFO any more because
KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are shared
by both kexec reboot and crash dumping.
Doing this makes codes and the corresponding config items more
logical (the right item depends on or is selected by the left item).
PROC_KCORE -----------> VMCORE_INFO
|----------> VMCORE_INFO
FA_DUMP----|
|----------> CRASH_RESERVE
---->VMCORE_INFO
/
|---->CRASH_RESERVE
KEXEC --| /|
|--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
KEXEC_FILE --| \ |
\---->CRASH_HOTPLUG
KEXEC --|
|--> KEXEC_CORE--> kexec reboot
KEXEC_FILE --|
Link: https://lkml.kernel.org/r/20240124051254.67105-6-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes
need be built in to avoid compiling error when building kexec code even
though the crash dumping functionality is not enabled. E.g
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------
After splitting out crashkernel reservation code and vmcoreinfo exporting
code, there's only crash related code left in kernel/crash_core.c. Now
move crash related codes from kexec_core.c to crash_core.c and only build it
in when CONFIG_CRASH_DUMP=y.
And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope,
or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP
ifdef in generic kernel files.
With these changes, crash_core codes are abstracted from kexec codes and
can be disabled at all if only kexec reboot feature is wanted.
Link: https://lkml.kernel.org/r/20240124051254.67105-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In kdump kernel, /proc/vmcore is an elf file mapping the crashed kernel's
old memory content. Its elf header is constructed in 1st kernel and passed
to kdump kernel via elfcorehdr_addr. Config CRASH_DUMP enables the code
of 1st kernel's old memory accessing in different architectures.
Currently, config FA_DUMP has dependency on CRASH_DUMP because fadump
needs access global variable 'elfcorehdr_addr' to judge if it's in
kdump kernel within function is_kdump_kernel(). In the current
kernel/crash_dump.c, variable 'elfcorehdr_addr' is defined, and function
setup_elfcorehdr() used to parse kernel parameter to fetch the passed
value of elfcorehdr_addr. Only for accessing elfcorehdr_addr, FA_DUMP
really doesn't have to depends on CRASH_DUMP.
To remove the dependency of FA_DUMP on CRASH_DUMP to avoid confusion,
rename kernel/crash_dump.c to kernel/elfcorehdr.c, and build it when
CONFIG_VMCORE_INFO is ebabled. With this, FA_DUMP doesn't need to depend
on CRASH_DUMP.
[bhe@redhat.com: power/fadump: make FA_DUMP select CRASH_DUMP]
Link: https://lkml.kernel.org/r/Zb8D1ASrgX0qVm9z@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20240124051254.67105-4-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now move the relevant codes into separate files:
kernel/crash_reserve.c, include/linux/crash_reserve.h.
And add config item CRASH_RESERVE to control its enabling.
And also update the old ifdeffery of CONFIG_CRASH_CORE, including of
<linux/crash_core.h> and config item dependency on CRASH_CORE
accordingly.
And also do renaming as follows:
- arch/xxx/kernel/{crash_core.c => vmcore_info.c}
because they are only related to vmcoreinfo exporting on x86, arm64,
riscv.
And also Remove config item CRASH_CORE, and rely on CONFIG_KEXEC_CORE to
decide if build in crash_core.c.
[yang.lee@linux.alibaba.com: remove duplicated include in vmcore_info.c]
Link: https://lkml.kernel.org/r/20240126005744.16561-1-yang.lee@linux.alibaba.com
Link: https://lkml.kernel.org/r/20240124051254.67105-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Split crash out from kexec and clean up related config
items", v3.
Motivation:
=============
Previously, LKP reported a building error. When investigating, it can't
be resolved reasonablly with the present messy kdump config items.
https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/
The kdump (crash dumping) related config items could causes confusions:
Firstly,
CRASH_CORE enables codes including
- crashkernel reservation;
- elfcorehdr updating;
- vmcoreinfo exporting;
- crash hotplug handling;
Now fadump of powerpc, kcore dynamic debugging and kdump all selects
CRASH_CORE, while fadump
- fadump needs crashkernel parsing, vmcoreinfo exporting, and accessing
global variable 'elfcorehdr_addr';
- kcore only needs vmcoreinfo exporting;
- kdump needs all of the current kernel/crash_core.c.
So only enabling PROC_CORE or FA_DUMP will enable CRASH_CORE, this
mislead people that we enable crash dumping, actual it's not.
Secondly,
It's not reasonable to allow KEXEC_CORE select CRASH_CORE.
Because KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are
shared by both kexec reboot and kdump. We could want kexec reboot,
but disable kdump. In that case, CRASH_CORE should not be selected.
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------
Thirdly,
It's not reasonable to allow CRASH_DUMP select KEXEC_CORE.
That could make KEXEC_CORE, CRASH_DUMP are enabled independently from
KEXEC or KEXEC_FILE. However, w/o KEXEC or KEXEC_FILE, the KEXEC_CORE
code built in doesn't make any sense because no kernel loading or
switching will happen to utilize the KEXEC_CORE code.
---------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
---------------------
In this case, what is worse, on arch sh and arm, KEXEC relies on MMU,
while CRASH_DUMP can still be enabled when !MMU, then compiling error is
seen as the lkp test robot reported in above link.
------arch/sh/Kconfig------
config ARCH_SUPPORTS_KEXEC
def_bool MMU
config ARCH_SUPPORTS_CRASH_DUMP
def_bool BROKEN_ON_SMP
---------------------------
Changes:
===========
1, split out crash_reserve.c from crash_core.c;
2, split out vmcore_infoc. from crash_core.c;
3, move crash related codes in kexec_core.c into crash_core.c;
4, remove dependency of FA_DUMP on CRASH_DUMP;
5, clean up kdump related config items;
6, wrap up crash codes in crash related ifdefs on all 8 arch-es
which support crash dumping, except of ppc;
Achievement:
===========
With above changes, I can rearrange the config item logic as below (the right
item depends on or is selected by the left item):
PROC_KCORE -----------> VMCORE_INFO
|----------> VMCORE_INFO
FA_DUMP----|
|----------> CRASH_RESERVE
---->VMCORE_INFO
/
|---->CRASH_RESERVE
KEXEC --| /|
|--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
KEXEC_FILE --| \ |
\---->CRASH_HOTPLUG
KEXEC --|
|--> KEXEC_CORE (for kexec reboot only)
KEXEC_FILE --|
Test
========
On all 8 architectures, including x86_64, arm64, s390x, sh, arm, mips,
riscv, loongarch, I did below three cases of config item setting and
building all passed. Take configs on x86_64 as exampmle here:
(1) Both CONFIG_KEXEC and KEXEC_FILE is unset, then all kexec/kdump
items are unset automatically:
# Kexec and crash features
# CONFIG_KEXEC is not set
# CONFIG_KEXEC_FILE is not set
# end of Kexec and crash features
(2) set CONFIG_KEXEC_FILE and 'make olddefconfig':
---------------
# Kexec and crash features
CONFIG_CRASH_RESERVE=y
CONFIG_VMCORE_INFO=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
CONFIG_CRASH_DUMP=y
CONFIG_CRASH_HOTPLUG=y
CONFIG_CRASH_MAX_MEMORY_RANGES=8192
# end of Kexec and crash features
---------------
(3) unset CONFIG_CRASH_DUMP in case 2 and execute 'make olddefconfig':
------------------------
# Kexec and crash features
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
# end of Kexec and crash features
------------------------
Note:
For ppc, it needs investigation to make clear how to split out crash
code in arch folder. Hope Hari and Pingfan can help have a look, see if
it's doable. Now, I make it either have both kexec and crash enabled, or
disable both of them altogether.
This patch (of 14):
Both kdump and fa_dump of ppc rely on crashkernel reservation. Move the
relevant codes into separate files: crash_reserve.c,
include/linux/crash_reserve.h.
And also add config item CRASH_RESERVE to control its enabling of the
codes. And update config items which has relationship with crashkernel
reservation.
And also change ifdeffery from CONFIG_CRASH_CORE to CONFIG_CRASH_RESERVE
when those scopes are only crashkernel reservation related.
And also rename arch/XXX/include/asm/{crash_core.h => crash_reserve.h} on
arm64, x86 and risc-v because those architectures' crash_core.h is only
related to crashkernel reservation.
[akpm@linux-foundation.org: s/CRASH_RESEERVE/CRASH_RESERVE/, per Klara Modin]
Link: https://lkml.kernel.org/r/20240124051254.67105-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20240124051254.67105-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patch tends to simplify the function in question, by removing an
extra stack "objp" variable, returning back to an early exit approach if
spin_trylock() fails or VA was not found.
Link: https://lkml.kernel.org/r/20240124180920.50725-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patch adds extra explanation of recently added vmap node layer based
on community feedback. No functional change.
Link: https://lkml.kernel.org/r/20240124180920.50725-1-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The added shrinker is used to return back current cached VAs into a global
vmap space, when a system enters into a low memory mode.
Link: https://lkml.kernel.org/r/20240102184633.748113-12-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A number of nodes which are used in the alloc/free paths is set based on
num_possible_cpus() in a system. Please note a high limit threshold
though is fixed and corresponds to 128 nodes.
For 32-bit or single core systems an access to a global vmap heap is not
balanced. Such small systems do not suffer from lock contentions due to
low number of CPUs. In such case the nr_nodes is equal to 1.
Test on AMD Ryzen Threadripper 3970X 32-Core Processor: sudo
./test_vmalloc.sh run_test_mask=7 nr_threads=64
<default perf>
94.41% 0.89% [kernel] [k] _raw_spin_lock
93.35% 93.07% [kernel] [k] native_queued_spin_lock_slowpath
76.13% 0.28% [kernel] [k] __vmalloc_node_range
72.96% 0.81% [kernel] [k] alloc_vmap_area
56.94% 0.00% [kernel] [k] __get_vm_area_node
41.95% 0.00% [kernel] [k] vmalloc
37.15% 0.01% [test_vmalloc] [k] full_fit_alloc_test
35.17% 0.00% [kernel] [k] ret_from_fork_asm
35.17% 0.00% [kernel] [k] ret_from_fork
35.17% 0.00% [kernel] [k] kthread
35.08% 0.00% [test_vmalloc] [k] test_func
34.45% 0.00% [test_vmalloc] [k] fix_size_alloc_test
28.09% 0.01% [test_vmalloc] [k] long_busy_list_alloc_test
23.53% 0.25% [kernel] [k] vfree.part.0
21.72% 0.00% [kernel] [k] remove_vm_area
20.08% 0.21% [kernel] [k] find_unlink_vmap_area
2.34% 0.61% [kernel] [k] free_vmap_area_noflush
<default perf>
vs
<patch-series perf>
82.32% 0.22% [test_vmalloc] [k] long_busy_list_alloc_test
63.36% 0.02% [kernel] [k] vmalloc
63.34% 2.64% [kernel] [k] __vmalloc_node_range
30.42% 4.46% [kernel] [k] vfree.part.0
28.98% 2.51% [kernel] [k] __alloc_pages_bulk
27.28% 0.19% [kernel] [k] __get_vm_area_node
26.13% 1.50% [kernel] [k] alloc_vmap_area
21.72% 21.67% [kernel] [k] clear_page_rep
19.51% 2.43% [kernel] [k] _raw_spin_lock
16.61% 16.51% [kernel] [k] native_queued_spin_lock_slowpath
13.40% 2.07% [kernel] [k] free_unref_page
10.62% 0.01% [kernel] [k] remove_vm_area
9.02% 8.73% [kernel] [k] insert_vmap_area
8.94% 0.00% [kernel] [k] ret_from_fork_asm
8.94% 0.00% [kernel] [k] ret_from_fork
8.94% 0.00% [kernel] [k] kthread
8.29% 0.00% [test_vmalloc] [k] test_func
7.81% 0.05% [test_vmalloc] [k] full_fit_alloc_test
5.30% 4.73% [kernel] [k] purge_vmap_node
4.47% 2.65% [kernel] [k] free_vmap_area_noflush
<patch-series perf>
confirms that a native_queued_spin_lock_slowpath goes down to
16.51% percent from 93.07%.
The throughput is ~12x higher:
urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=7 nr_threads=64
Run the test with following parameters: run_test_mask=7 nr_threads=64
Done.
Check the kernel ring buffer to see the summary.
real 10m51.271s
user 0m0.013s
sys 0m0.187s
urezki@pc638:~$
urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=7 nr_threads=64
Run the test with following parameters: run_test_mask=7 nr_threads=64
Done.
Check the kernel ring buffer to see the summary.
real 0m51.301s
user 0m0.015s
sys 0m0.040s
urezki@pc638:~$
Link: https://lkml.kernel.org/r/20240102184633.748113-11-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Allocated areas are spread among nodes, it implies that the scanning has
to be performed individually of each node in order to dump all existing
VAs.
Link: https://lkml.kernel.org/r/20240102184633.748113-10-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Extend the vread_iter() to be able to perform a sequential reading of VAs
which are spread among multiple nodes. So a data read over the /dev/kmem
correctly reflects a vmalloc memory layout.
Link: https://lkml.kernel.org/r/20240102184633.748113-9-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Invoke a kmemleak_scan_area() function only for newly allocated objects to
add a scan area within that object. There is no reason to add a same scan
area(pointer to beginning or inside the object) several times. If a VA is
obtained from the cache its scan area has already been associated.
Link: https://lkml.kernel.org/r/20240202190628.47806-1-urezki@gmail.com
Fixes: 7db166b4aa0d ("mm: vmalloc: offload free_vmap_area_lock lock")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Concurrent access to a global vmap space is a bottle-neck. We can
simulate a high contention by running a vmalloc test suite.
To address it, introduce an effective vmap node logic. Each node behaves
as independent entity. When a node is accessed it serves a request
directly(if possible) from its pool.
This model has a size based pool for requests, i.e. pools are serialized
and populated based on object size and real demand. A maximum object size
that pool can handle is set to 256 pages.
This technique reduces a pressure on the global vmap lock.
Link: https://lkml.kernel.org/r/20240102184633.748113-8-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Similar to busy VA, lazily-freed area is stored to a node it belongs to.
Such approach does not require any global locking primitive, instead an
access becomes scalable what mitigates a contention.
This patch removes a global purge-lock, global purge-tree and global purge
list.
Link: https://lkml.kernel.org/r/20240102184633.748113-7-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Earlier, vmap_area_list is exported to vmcoreinfo so that makedumpfile get
the base address of vmalloc area. Now, vmap_area_list is empty, so export
VMALLOC_START to vmcoreinfo instead, and remove vmap_area_list.
[urezki@gmail.com: fix a warning in the crash_save_vmcoreinfo_init()]
Link: https://lkml.kernel.org/r/20240111192329.449189-1-urezki@gmail.com
Link: https://lkml.kernel.org/r/20240102184633.748113-6-urezki@gmail.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Store allocated objects in a separate nodes. A va->va_start address is
converted into a correct node where it should be placed and resided. An
addr_to_node() function is used to do a proper address conversion to
determine a node that contains a VA.
Such approach balances VAs across nodes as a result an access becomes
scalable. Number of nodes in a system depends on number of CPUs.
Please note:
1. As of now allocated VAs are bound to a node-0. It means the
patch does not give any difference comparing with a current
behavior;
2. The global vmap_area_lock, vmap_area_root are removed as there
is no need in it anymore. The vmap_area_list is still kept and
is _empty_. It is exported for a kexec only;
3. The vmallocinfo and vread() have to be reworked to be able to
handle multiple nodes.
[urezki@gmail.com: mark vmap_init_free_space() with __init tag]
Link: https://lkml.kernel.org/r/20240111132628.299644-1-urezki@gmail.com
[urezki@gmail.com: fix a wrong value passed to __find_vmap_area()]
Link: https://lkml.kernel.org/r/20240111121104.180993-1-urezki@gmail.com
Link: https://lkml.kernel.org/r/20240102184633.748113-5-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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A vmap_init_free_space() is a function that setups a vmap space and is
considered as part of initialization phase. Since a main entry which is
vmalloc_init(), has been moved down in vmalloc.c it makes sense to follow
the pattern.
There is no a functional change as a result of this patch.
Link: https://lkml.kernel.org/r/20240102184633.748113-4-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This patch renames the adjust_va_to_fit_type() function to va_clip() which
is shorter and more expressive.
There is no a functional change as a result of this patch.
Link: https://lkml.kernel.org/r/20240102184633.748113-3-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Mitigate a vmap lock contention", v3.
1. Motivation
- Offload global vmap locks making it scaled to number of CPUS;
- If possible and there is an agreement, we can remove the "Per cpu kva
allocator" to make the vmap code to be more simple;
- There were complaints from XFS folk that a vmalloc might be contented
on their workloads.
2. Design(high level overview)
We introduce an effective vmap node logic. A node behaves as independent
entity to serve an allocation request directly(if possible) from its pool.
That way it bypasses a global vmap space that is protected by its own
lock.
An access to pools are serialized by CPUs. Number of nodes are equal to
number of CPUs in a system. Please note the high threshold is bound to
128 nodes.
Pools are size segregated and populated based on system demand. The
maximum alloc request that can be stored into a segregated storage is 256
pages. The lazily drain path decays a pool by 25% as a first step and as
second populates it by fresh freed VAs for reuse instead of returning them
into a global space.
When a VA is obtained(alloc path), it is stored in separate nodes. A
va->va_start address is converted into a correct node where it should be
placed and resided. Doing so we balance VAs across the nodes as a result
an access becomes scalable. The addr_to_node() function does a proper
address conversion to a correct node.
A vmap space is divided on segments with fixed size, it is 16 pages. That
way any address can be associated with a segment number. Number of
segments are equal to num_possible_cpus() but not grater then 128. The
numeration starts from 0. See below how it is converted:
static inline unsigned int
addr_to_node_id(unsigned long addr)
{
return (addr / zone_size) % nr_nodes;
}
On a free path, a VA can be easily found by converting its "va_start"
address to a certain node it resides. It is moved from "busy" data to
"lazy" data structure. Later on, as noted earlier, the lazy kworker
decays each node pool and populates it by fresh incoming VAs. Please
note, a VA is returned to a node that did an alloc request.
3. Test on AMD Ryzen Threadripper 3970X 32-Core Processor
sudo ./test_vmalloc.sh run_test_mask=7 nr_threads=64
<default perf>
94.41% 0.89% [kernel] [k] _raw_spin_lock
93.35% 93.07% [kernel] [k] native_queued_spin_lock_slowpath
76.13% 0.28% [kernel] [k] __vmalloc_node_range
72.96% 0.81% [kernel] [k] alloc_vmap_area
56.94% 0.00% [kernel] [k] __get_vm_area_node
41.95% 0.00% [kernel] [k] vmalloc
37.15% 0.01% [test_vmalloc] [k] full_fit_alloc_test
35.17% 0.00% [kernel] [k] ret_from_fork_asm
35.17% 0.00% [kernel] [k] ret_from_fork
35.17% 0.00% [kernel] [k] kthread
35.08% 0.00% [test_vmalloc] [k] test_func
34.45% 0.00% [test_vmalloc] [k] fix_size_alloc_test
28.09% 0.01% [test_vmalloc] [k] long_busy_list_alloc_test
23.53% 0.25% [kernel] [k] vfree.part.0
21.72% 0.00% [kernel] [k] remove_vm_area
20.08% 0.21% [kernel] [k] find_unlink_vmap_area
2.34% 0.61% [kernel] [k] free_vmap_area_noflush
<default perf>
vs
<patch-series perf>
82.32% 0.22% [test_vmalloc] [k] long_busy_list_alloc_test
63.36% 0.02% [kernel] [k] vmalloc
63.34% 2.64% [kernel] [k] __vmalloc_node_range
30.42% 4.46% [kernel] [k] vfree.part.0
28.98% 2.51% [kernel] [k] __alloc_pages_bulk
27.28% 0.19% [kernel] [k] __get_vm_area_node
26.13% 1.50% [kernel] [k] alloc_vmap_area
21.72% 21.67% [kernel] [k] clear_page_rep
19.51% 2.43% [kernel] [k] _raw_spin_lock
16.61% 16.51% [kernel] [k] native_queued_spin_lock_slowpath
13.40% 2.07% [kernel] [k] free_unref_page
10.62% 0.01% [kernel] [k] remove_vm_area
9.02% 8.73% [kernel] [k] insert_vmap_area
8.94% 0.00% [kernel] [k] ret_from_fork_asm
8.94% 0.00% [kernel] [k] ret_from_fork
8.94% 0.00% [kernel] [k] kthread
8.29% 0.00% [test_vmalloc] [k] test_func
7.81% 0.05% [test_vmalloc] [k] full_fit_alloc_test
5.30% 4.73% [kernel] [k] purge_vmap_node
4.47% 2.65% [kernel] [k] free_vmap_area_noflush
<patch-series perf>
confirms that a native_queued_spin_lock_slowpath goes down to
16.51% percent from 93.07%.
The throughput is ~12x higher:
urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=7 nr_threads=64
Run the test with following parameters: run_test_mask=7 nr_threads=64
Done.
Check the kernel ring buffer to see the summary.
real 10m51.271s
user 0m0.013s
sys 0m0.187s
urezki@pc638:~$
urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=7 nr_threads=64
Run the test with following parameters: run_test_mask=7 nr_threads=64
Done.
Check the kernel ring buffer to see the summary.
real 0m51.301s
user 0m0.015s
sys 0m0.040s
urezki@pc638:~$
This patch (of 11):
Currently __alloc_vmap_area() function contains an open codded logic that
finds and adjusts a VA based on allocation request.
Introduce a va_alloc() helper that adjusts found VA only. There is no a
functional change as a result of this patch.
Link: https://lkml.kernel.org/r/20240102184633.748113-1-urezki@gmail.com
Link: https://lkml.kernel.org/r/20240102184633.748113-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update page_owner documentation including the new page_owner_stacks
feature to show how it can be used.
Link: https://lkml.kernel.org/r/20240215215907.20121-8-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Marco Elver <elver@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We want to be able to filter out the stacks based on a threshold we can
can tune. By writing to 'count_threshold' file, we can adjust the
threshold value.
Link: https://lkml.kernel.org/r/20240215215907.20121-7-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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