| Age | Commit message (Collapse) | Author |
|---|
|
The function for allocating and initialize a 'struct damos' object,
damon_new_scheme(), is not initializing damos->walk_completed field. Only
damos_walk_complete() is setting the field. Hence the field will be
eventually set and used correctly from second damos_walk() call for the
scheme. But the first damos_walk() could mistakenly not walk on the
regions. Actually, a common usage of DAMOS for taking an access pattern
snapshot is installing a monitoring-purpose DAMOS scheme, doing
damos_walk() to retrieve the snapshot, and then removing the scheme.
DAMON user-space tool (damo) also gets runtime snapshot in the way. Hence
the problem can continuously happen in such use cases. Initialize it
properly in the allocation function.
Link: https://lkml.kernel.org/r/20250228174450.41472-1-sj@kernel.org
Fixes: bf0eaba0ff9c ("mm/damon/core: implement damos_walk()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Filtering decisions are made in filters evaluation order. Once a decision
is made by a filter, filters that scheduled to be evaluated after the
decision-made filter should just respect it. This is the intended and
documented behavior. Since core layer-handled filters are evaluated
before operations layer-handled filters, decisions made on core layer
should respected by ops layer.
In case of reject filters, the decision is respected, since core
layer-rejected regions are not passed to ops layer. But in case of allow
filters, ops layer filters don't know if the region has passed to them
because it was allowed by core filters or just because it didn't match to
any core layer. The current wrong implementation assumes it was due to
not matched by any core filters. As a reuslt, the decision is not
respected. Pass the missing information to ops layer using a new filed in
'struct damos', and make the ops layer filters respect it.
Link: https://lkml.kernel.org/r/20250228175336.42781-1-sj@kernel.org
Fixes: 491fee286e56 ("mm/damon/core: support damos_filter->allow")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove hard-coded strings by using the str_high_low() helper function.
Link: https://lkml.kernel.org/r/20250116204216.106999-2-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
DAMON API users should set damos_filter->allow manually to use a DAMOS
allow-filter, since damos_new_filter() unsets the field always. It is
cumbersome and easy to mistake. Add an arugment for setting the field to
damos_new_filter().
Link: https://lkml.kernel.org/r/20250109175126.57878-6-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>
|
|
DAMOS filters supports allowing behavior, but the core layer's DAMOS
filters handling logic still assumes only rejecting (filtering-out)
behavior. Update the logic to aware of and respect the behavioral
decision by reading damos_filter->allow when making the decision to
exclude a region or not.
Link: https://lkml.kernel.org/r/20250109175126.57878-4-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>
|
|
DAMOS filters work as only exclusive (reject) filters. This makes it easy
to be confused, and restrictive at combining multiple filters for covering
various types of memory.
Add a field named 'allow' to damos_filter. The field will be used to
indicate whether the filter should work for inclusion or exclusion. To
keep the old behavior, set it as 'false' (work as exclusive filter) by
default, from damos_new_filter().
Following two commits will make the core and operations set layers, which
handles damos_filter objects, respect the field, respectively.
Link: https://lkml.kernel.org/r/20250109175126.57878-3-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>
|
|
damos_walk_control->walk_fn()
Total size of memory that passed DAMON operations set layer-handled DAMOS
filters per scheme is provided to DAMON core API and ABI (sysfs interface)
users. Having it per-region in non-accumulated way can provide it in
finer granularity. Provide it to damos_walk() core API users, by passing
the data to damos_walk_control->walk_fn().
Link: https://lkml.kernel.org/r/20250106193401.109161-13-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>
|
|
Implement a new per-DAMOS scheme statistic field, namely
sz_ops_filter_passed, using the changed damon_operations->apply_scheme()
interface. It counts total bytes of memory that given DAMOS action tried
to be applied, and passed the operations layer handled region-internal
filters of the scheme. DAMON API users can access it using DAMON-internal
safe access features such as damon_call() and/or damos_walk().
Link: https://lkml.kernel.org/r/20250106193401.109161-8-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>
|
|
Some DAMOS filter types including those for young page, anon page, and
belonging memcg are handled by underlying DAMON operations set
implementation, via damon_operations->apply_scheme() interface. How many
bytes of the region have passed the filter can be useful for DAMOS scheme
tuning and access pattern monitoring. Modify the interface to let the
callback implementation reports back the number if possible.
Link: https://lkml.kernel.org/r/20250106193401.109161-5-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>
|
|
Introduce a new core layer interface, damos_walk(). It aims to replace
some damon_callback usages that access DAMOS schemes applied regions of
ongoing kdamond with additional synchronizations. It receives a function
pointer and asks kdamond to invoke it for any region that it tried to
apply any DAMOS action within one scheme apply interval for every scheme
of it. The function further waits until the kdamond finishes the
invocations for every scheme, or cancels the request, and returns.
The kdamond invokes the function as requested within the main loop. If it
is deactivated by DAMOS watermarks or going out of the main loop, it marks
the request as canceled, so that damos_walk() can wakeup and return.
Link: https://lkml.kernel.org/r/20250103174400.54890-8-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>
|
|
Introduce a new DAMON core API function, damon_call(). It aims to replace
some damon_callback usages that access damon_ctx of ongoing kdamond with
additional synchronizations. It receives a function pointer, let the
parallel kdamond invokes the function, and returns after the invocation is
finished, or canceled due to some races.
kdamond invokes the function inside the main loop after sampling is done.
If it is deactivated by DAMOS watermarks or already out of the main loop,
mark the request as canceled so that damon_call() can wakeup and return.
Link: https://lkml.kernel.org/r/20250103174400.54890-4-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>
|
|
damos_set_effective_quota() checks quota contidions but there are some
duplicate checks for quota->goals inside.
This patch reduces one of if statement to simplify the esz calculation
logic by setting esz as ULONG_MAX by default.
Link: https://lkml.kernel.org/r/20241125184307.41746-1-sj@kernel.org
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
damon_commit_schemes() ignores quota goals and filters of the newly
committed schemes. This makes users confused about the behaviors.
Correctly handle those inputs.
Link: https://lkml.kernel.org/r/20241222231222.85060-3-sj@kernel.org
Fixes: 9cb3d0b9dfce ("mm/damon/core: implement DAMON context commit function")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon/core: fix memory leaks and ignored inputs from
damon_commit_ctx()".
Due to two bugs in damon_commit_targets() and damon_commit_schemes(),
which are called from damon_commit_ctx(), some user inputs can be ignored,
and some mmeory objects can be leaked. Fix those.
Note that only DAMON sysfs interface users are affected. Other DAMON core
API user modules that more focused more on simple and dedicated production
usages, including DAMON_RECLAIM and DAMON_LRU_SORT are not using the buggy
function in the way, so not affected.
This patch (of 2):
When new DAMON targets are added via damon_commit_targets(), the newly
created targets are not deallocated when updating the internal data
(damon_commit_target()) is failed. Worse yet, even if the setup is
successfully done, the new target is not linked to the context. Hence,
the new targets are always leaked regardless of the internal data setup
failure. Fix the leaks.
Link: https://lkml.kernel.org/r/20241222231222.85060-2-sj@kernel.org
Fixes: 9cb3d0b9dfce ("mm/damon/core: implement DAMON context commit function")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"A rather large update for timekeeping and timers:
- The final step to get rid of auto-rearming posix-timers
posix-timers are currently auto-rearmed by the kernel when the
signal of the timer is ignored so that the timer signal can be
delivered once the corresponding signal is unignored.
This requires to throttle the timer to prevent a DoS by small
intervals and keeps the system pointlessly out of low power states
for no value. This is a long standing non-trivial problem due to
the lock order of posix-timer lock and the sighand lock along with
life time issues as the timer and the sigqueue have different life
time rules.
Cure this by:
- Embedding the sigqueue into the timer struct to have the same
life time rules. Aside of that this also avoids the lookup of
the timer in the signal delivery and rearm path as it's just a
always valid container_of() now.
- Queuing ignored timer signals onto a seperate ignored list.
- Moving queued timer signals onto the ignored list when the
signal is switched to SIG_IGN before it could be delivered.
- Walking the ignored list when SIG_IGN is lifted and requeue the
signals to the actual signal lists. This allows the signal
delivery code to rearm the timer.
This also required to consolidate the signal delivery rules so they
are consistent across all situations. With that all self test
scenarios finally succeed.
- Core infrastructure for VFS multigrain timestamping
This is required to allow the kernel to use coarse grained time
stamps by default and switch to fine grained time stamps when inode
attributes are actively observed via getattr().
These changes have been provided to the VFS tree as well, so that
the VFS specific infrastructure could be built on top.
- Cleanup and consolidation of the sleep() infrastructure
- Move all sleep and timeout functions into one file
- Rework udelay() and ndelay() into proper documented inline
functions and replace the hardcoded magic numbers by proper
defines.
- Rework the fsleep() implementation to take the reality of the
timer wheel granularity on different HZ values into account.
Right now the boundaries are hard coded time ranges which fail
to provide the requested accuracy on different HZ settings.
- Update documentation for all sleep/timeout related functions
and fix up stale documentation links all over the place
- Fixup a few usage sites
- Rework of timekeeping and adjtimex(2) to prepare for multiple PTP
clocks
A system can have multiple PTP clocks which are participating in
seperate and independent PTP clock domains. So far the kernel only
considers the PTP clock which is based on CLOCK TAI relevant as
that's the clock which drives the timekeeping adjustments via the
various user space daemons through adjtimex(2).
The non TAI based clock domains are accessible via the file
descriptor based posix clocks, but their usability is very limited.
They can't be accessed fast as they always go all the way out to
the hardware and they cannot be utilized in the kernel itself.
As Time Sensitive Networking (TSN) gains traction it is required to
provide fast user and kernel space access to these clocks.
The approach taken is to utilize the timekeeping and adjtimex(2)
infrastructure to provide this access in a similar way how the
kernel provides access to clock MONOTONIC, REALTIME etc.
Instead of creating a duplicated infrastructure this rework
converts timekeeping and adjtimex(2) into generic functionality
which operates on pointers to data structures instead of using
static variables.
This allows to provide time accessors and adjtimex(2) functionality
for the independent PTP clocks in a subsequent step.
- Consolidate hrtimer initialization
hrtimers are set up by initializing the data structure and then
seperately setting the callback function for historical reasons.
That's an extra unnecessary step and makes Rust support less
straight forward than it should be.
Provide a new set of hrtimer_setup*() functions and convert the
core code and a few usage sites of the less frequently used
interfaces over.
The bulk of the htimer_init() to hrtimer_setup() conversion is
already prepared and scheduled for the next merge window.
- Drivers:
- Ensure that the global timekeeping clocksource is utilizing the
cluster 0 timer on MIPS multi-cluster systems.
Otherwise CPUs on different clusters use their cluster specific
clocksource which is not guaranteed to be synchronized with
other clusters.
- Mostly boring cleanups, fixes, improvements and code movement"
* tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits)
posix-timers: Fix spurious warning on double enqueue versus do_exit()
clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties
clocksource/drivers/gpx: Remove redundant casts
clocksource/drivers/timer-ti-dm: Fix child node refcount handling
dt-bindings: timer: actions,owl-timer: convert to YAML
clocksource/drivers/ralink: Add Ralink System Tick Counter driver
clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource
clocksource/drivers/timer-ti-dm: Don't fail probe if int not found
clocksource/drivers:sp804: Make user selectable
clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions
hrtimers: Delete hrtimer_init_on_stack()
alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack()
io_uring: Switch to use hrtimer_setup_on_stack()
sched/idle: Switch to use hrtimer_setup_on_stack()
hrtimers: Delete hrtimer_init_sleeper_on_stack()
wait: Switch to use hrtimer_setup_sleeper_on_stack()
timers: Switch to use hrtimer_setup_sleeper_on_stack()
net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack()
futex: Switch to use hrtimer_setup_sleeper_on_stack()
fs/aio: Switch to use hrtimer_setup_sleeper_on_stack()
...
|
|
damon_feed_loop_next_input() is inefficient and fragile to overflows.
Specifically, 'score_goal_diff_bp' calculation can overflow when 'score'
is high. The calculation is actually unnecessary at all because 'goal' is
a constant of value 10,000. Calculation of 'compensation' is again
fragile to overflow. Final calculation of return value for under-achiving
case is again fragile to overflow when the current score is
under-achieving the target.
Add two corner cases handling at the beginning of the function to make the
body easier to read, and rewrite the body of the function to avoid
overflows and the unnecessary bp value calcuation.
Link: https://lkml.kernel.org/r/20241031161203.47751-1-sj@kernel.org
Fixes: 9294a037c015 ("mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/944f3d5b-9177-48e7-8ec9-7f1331a3fea3@roeck-us.net
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: <stable@vger.kernel.org> [6.8.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
DAMON's logics to determine if this is the time to apply damos schemes
assumes next_apply_sis is always set larger than current
passed_sample_intervals. And therefore assume continuously incrementing
passed_sample_intervals will make it reaches to the next_apply_sis in
future. The logic hence does apply the scheme and update next_apply_sis
only if passed_sample_intervals is same to next_apply_sis.
If Schemes apply interval is set as zero, however, next_apply_sis is set
same to current passed_sample_intervals, respectively. And
passed_sample_intervals is incremented before doing the next_apply_sis
check. Hence, next_apply_sis becomes larger than next_apply_sis, and the
logic says it is not the time to apply schemes and update next_apply_sis.
In other words, DAMON stops applying schemes until passed_sample_intervals
overflows.
Based on the documents and the common sense, a reasonable behavior for
such inputs would be applying the schemes for every sampling interval.
Handle the case by removing the assumption.
Link: https://lkml.kernel.org/r/20241031183757.49610-3-sj@kernel.org
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.7.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon/core: fix handling of zero non-sampling intervals".
DAMON's internal intervals accounting logic is not correctly handling
non-sampling intervals of zero values for a wrong assumption. This could
cause unexpected monitoring behavior, and even result in infinite hang of
DAMON sysfs interface user threads in case of zero aggregation interval.
Fix those by updating the intervals accounting logic. For details of the
root case and solutions, please refer to commit messages of fixes.
This patch (of 2):
DAMON's logics to determine if this is the time to do aggregation and ops
update assumes next_{aggregation,ops_update}_sis are always set larger
than current passed_sample_intervals. And therefore it further assumes
continuously incrementing passed_sample_intervals every sampling interval
will make it reaches to the next_{aggregation,ops_update}_sis in future.
The logic therefore make the action and update
next_{aggregation,ops_updaste}_sis only if passed_sample_intervals is same
to the counts, respectively.
If Aggregation interval or Ops update interval are zero, however,
next_aggregation_sis or next_ops_update_sis are set same to current
passed_sample_intervals, respectively. And passed_sample_intervals is
incremented before doing the next_{aggregation,ops_update}_sis check.
Hence, passed_sample_intervals becomes larger than
next_{aggregation,ops_update}_sis, and the logic says it is not the time
to do the action and update next_{aggregation,ops_update}_sis forever,
until an overflow happens. In other words, DAMON stops doing aggregations
or ops updates effectively forever, and users cannot get monitoring
results.
Based on the documents and the common sense, a reasonable behavior for
such inputs is doing an aggregation and an ops update for every sampling
interval. Handle the case by removing the assumption.
Note that this could incur particular real issue for DAMON sysfs interface
users, in case of zero Aggregation interval. When user starts DAMON with
zero Aggregation interval and asks online DAMON parameter tuning via DAMON
sysfs interface, the request is handled by the aggregation callback.
Until the callback finishes the work, the user who requested the online
tuning just waits. Hence, the user will be stuck until the
passed_sample_intervals overflows.
Link: https://lkml.kernel.org/r/20241031183757.49610-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20241031183757.49610-2-sj@kernel.org
Fixes: 4472edf63d66 ("mm/damon/core: use number of passed access sampling as a timer")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.7.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The upper bound for usleep_range_idle() was taken from the outdated
documentation. As a recommondation for the upper bound of usleep_range()
depends on HZ configuration it is not possible to hard code it.
Use the define "USLEEP_RANGE_UPPER_BOUND" instead.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-8-dc8b907cb62f@linutronix.de
|
|
usleep_idle_range() is a variant of usleep_range(). Both are using
usleep_range_state() as a base. To be able to find all the related
functions in one go, rename it usleep_idle_range() to usleep_range_idle().
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-4-dc8b907cb62f@linutronix.de
|
|
aggr_interval is zero
The aggregation interval of test purpose damon_attrs for
damon_test_nr_accesses_to_accesses_bp() becomes zero on 32 bit
architecture, since size of int and long types are same. As a result,
damon_nr_accesses_to_accesses_bp() call with the test data triggers
divide-by-zero exception. damon_nr_accesses_to_accesses_bp() shouldn't
be called with such data, and the non-test code avoids that by checking
the case on damon_update_monitoring_results(). Skip the test code in
the case, and add an explicit caution of the case on the comment for the
test target function.
Link: https://lkml.kernel.org/r/20240905162423.74053-1-sj@kernel.org
Fixes: 5e06ad590096 ("mm/damon/core-test: test max_nr_accesses overflow caused divide-by-zero")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/c771b962-a58f-435b-89e4-1211a9323181@roeck-us.net
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
with per-context one
Replace the usage of per-quota region priorities histogram buffer with the
per-context one. After this change, the per-quota histogram is not used
by anyone, and hence it is ready to be removed.
Link: https://lkml.kernel.org/r/20240826042323.87025-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "replace per-quota region priorities histogram buffer with
per-context one".
Each DAMOS quota (struct damos_quota) maintains a histogram for total
regions size per its prioritization score. DAMOS calcultes minimum
prioritization score of regions that are ok to apply the DAMOS action to
while respecting the quota. The histogram is constructed only for the
calculation of the minimum score in damos_adjust_quota() for each quota
which called by kdamond_fn().
Hence, there is no real reason to have per-quota histogram. Only
per-kdamond histogram is needed, since parallel kdamonds could have races
otherwise. The current implementation is only wasting the memory, and can
easily cause unintended stack usage[1].
So, introducing a per-kdamond histogram and replacing the per-quota one
with it would be the right solution for the issue. However, supporting
multiple DAMON contexts per kdamond is still an ongoing work[2] without a
clear estimated time of arrival. Meanwhile, per-context histogram could
be an effective and straightforward solution having no blocker. Let's fix
the problem first in the way.
This patch (of 4):
Introduce per-context buffer for region priority scores-total size
histogram. Same to the per-quota one (->histogram of struct damos_quota),
the new buffer is hidden from DAMON API users by being defined as a
private field of DAMON context structure. It is dynamically allocated and
de-allocated at the beginning and ending of the execution of the kdamond
by kdamond_fn() itself.
[1] commit 0742cadf5e4c ("mm/damon/lru_sort: adjust local variable to dynamic allocation")
[2] https://lore.kernel.org/20240531122320.909060-1-yorha.op@gmail.com
Link: https://lkml.kernel.org/r/20240826042323.87025-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826042323.87025-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There was a discussion about better places for kunit test code[1] and test
file name suffix[2]. Folowwing the conclusion, move kunit tests for DAMON
to mm/damon/tests/ subdirectory and rename those.
[1] https://lore.kernel.org/CABVgOS=pUdWb6NDHszuwb1HYws4a1-b1UmN=i8U_ED7HbDT0mg@mail.gmail.com
[2] https://lore.kernel.org/CABVgOSmKwPq7JEpHfS6sbOwsR0B-DBDk_JP-ZD9s9ZizvpUjbQ@mail.gmail.com
Link: https://lkml.kernel.org/r/20240827030336.7930-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
crashes from deferred split racing folio migration", needed by "mm:
migrate: split folio_migrate_mapping()".
|
|
DAMON keeps the number of regions under max_nr_regions by skipping regions
split operations when doing so can make the number higher than the limit.
It works well for preventing violation of the limit. But, if somehow the
violation happens, it cannot recovery well depending on the situation. In
detail, if the real number of regions having different access pattern is
higher than the limit, the mechanism cannot reduce the number below the
limit. In such a case, the system could suffer from high monitoring
overhead of DAMON.
The violation can actually happen. For an example, the user could reduce
max_nr_regions while DAMON is running, to be lower than the current number
of regions. Fix the problem by repeating the merge operations with
increasing aggressiveness in kdamond_merge_regions() for the case, until
the limit is met.
[sj@kernel.org: increase regions merge aggressiveness while respecting min_nr_regions]
Link: https://lkml.kernel.org/r/20240626164753.46270-1-sj@kernel.org
[sj@kernel.org: ensure max threshold attempt for max_nr_regions violation]
Link: https://lkml.kernel.org/r/20240627163153.75969-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240624175814.89611-1-sj@kernel.org
Fixes: b9a6ac4e4ede ("mm/damon: adaptively adjust regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Implement functions for supporting online DAMON context level parameters
update. The function receives two DAMON context structs. One is the
struct that currently being used by a kdamond and therefore to be updated.
The other one contains the parameters to be applied to the first one.
The function applies the new parameters to the destination struct while
keeping/updating the internal status and operation results. The function
should be called from DAMON context-update-safe place, like DAMON
callbacks.
Link: https://lkml.kernel.org/r/20240618181809.82078-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: introduce DAMON parameters online commit function".
DAMON context struct (damon_ctx) contains user requests (parameters),
internal status, and operation results. For flexible usages, DAMON API
users are encouraged to manually manipulate the struct. That works well
for simple use cases. However, it has turned out that it is not that
simple at least for online parameters udpate. It is easy to forget
properly maintaining internal status and operation results. Also, such
manual manipulation for online tuning is implemented multiple times on
DAMON API users including DAMON sysfs interface, DAMON_RECLAIM and
DAMON_LRU_SORT. As a result, we have multiple sources of bugs for same
problem. Actually we found and fixed a few bugs from online parameter
updating of DAMON API users.
Implement a function for online DAMON parameters update in core layer, and
replace DAMON API users' manual manipulation code for the use case. The
core layer function could still have bugs, but this change reduces the
source of bugs for the problem to one place.
This patch (of 12):
Implement functions for supporting online DAMOS quota goals parameters
update. The function receives two DAMOS quota structs. One is the struct
that currently being used by a kdamond and therefore to be updated. The
other one contains the parameters to be applied to the first one. The
function applies the new parameters to the destination struct while
keeping/updating the internal status. The function should be called from
parameters-update safe place, like DAMON callbacks.
Link: https://lkml.kernel.org/r/20240618181809.82078-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240618181809.82078-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patch adds target_nid under
/sys/kernel/mm/damon/admin/kdamonds/<N>/contexts/<N>/schemes/<N>/
The 'target_nid' can be used as the destination node for DAMOS actions
such as DAMOS_MIGRATE_{HOT,COLD} in the follow up patches.
[sj@kernel.org: document target_nid file]
Link: https://lkml.kernel.org/r/20240618213630.84846-3-sj@kernel.org
Link: https://lkml.kernel.org/r/20240614030010.751-4-honggyu.kim@sk.com
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Gregory Price <gregory.price@memverge.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
damos_wmark_metric_value's return value is 'unsigned long', so returning
-EINVAL as 'unsigned long' may turn out to be very different from the
expected one (using 2's complement) and treat as usual matric's value.
So, fix that, checking if returned value is not 0.
Link: https://lkml.kernel.org/r/20240506180238.53842-1-sj@kernel.org
Fixes: ee801b7dd782 ("mm/damon/schemes: activate schemes based on a watermarks mechanism")
Signed-off-by: Alex Rusuf <yorha.op@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: misc fixes and improvements".
Add miscelleneous and non-urgent fixes and improvements for DAMON code,
selftests, and documents.
This patch (of 10):
damos_quota_init_priv() function should initialize all private fields of
struct damos_quota. However, it is not initializing ->esz_bp field. This
could result in use of uninitialized variable from
damon_feed_loop_next_input() function. There is no such issue at the
moment because every caller of the function is passing damos_quota object
that already having the field zero value. But we cannot guarantee the
future, and the function is not doing what it is promising. A bug is a
bug. This fix is for preventing possible future issues.
Link: https://lkml.kernel.org/r/20240503180318.72798-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240503180318.72798-2-sj@kernel.org
Fixes: 9294a037c015 ("mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
'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>
|
|
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>
|
|
kdamond_apply_schemes() checks apply intervals of schemes and avoid
further applying any schemes if no scheme passed its apply interval.
However, the following schemes applying function, damon_do_apply_schemes()
iterates all schemes without the apply interval check. As a result, the
shortest apply interval is applied to all schemes. Fix the problem by
checking the apply interval in damon_do_apply_schemes().
Link: https://lkml.kernel.org/r/20240205201306.88562-1-sj@kernel.org
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.7.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: misc updates for 6.8".
Update comments, tests, and documents for DAMON.
This patch (of 6):
SeongJae is using his kernel.org account for DAMON development. Update
the old email addresses on the comments of DAMON source files.
Link: https://lkml.kernel.org/r/20231213190338.54146-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231213190338.54146-2-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>
|
|
|
|
The cleanup tasks of kdamond threads including reset of corresponding
DAMON context's ->kdamond field and decrease of global nr_running_ctxs
counter is supposed to be executed by kdamond_fn(). However, commit
0f91d13366a4 ("mm/damon: simplify stop mechanism") made neither
damon_start() nor damon_stop() ensure the corresponding kdamond has
started the execution of kdamond_fn().
As a result, the cleanup can be skipped if damon_stop() is called fast
enough after the previous damon_start(). Especially the skipped reset
of ->kdamond could cause a use-after-free.
Fix it by waiting for start of kdamond_fn() execution from
damon_start().
Link: https://lkml.kernel.org/r/20231208175018.63880-1-sj@kernel.org
Fixes: 0f91d13366a4 ("mm/damon: simplify stop mechanism")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: let users feed and tame/auto-tune DAMOS".
Introduce Aim-oriented Feedback-driven DAMOS Aggressiveness Auto-tuning.
It makes DAMOS self-tuned with periodic simple user feedback.
Background: DAMOS Control Difficulty
====================================
DAMOS helps users easily implement access pattern aware system operations.
However, controlling DAMOS in the wild is not that easy.
The basic way for DAMOS control is specifying the target access pattern.
In this approach, the user is assumed to well understand the access
pattern and the characteristics of the system and the workloads. Though
there are useful tools for that, it takes time and effort depending on the
complexity and the dynamicity of the system and the workloads. After all,
the access pattern consists of three ranges, namely the size, the access
rate, and the age of the regions. It means users need to tune six
parameters, which is anyway not a simple task.
One of the worst cases would be DAMOS being too aggressive like a
berserker, and therefore consuming too much system resource and making
unwanted radical system operations. To let users avoid such cases, DAMOS
allows users to set the upper-limit of the schemes' aggressiveness, namely
DAMOS quota. DAMOS further provides its best-effort under the limit by
prioritizing regions based on the access pattern of the regions. For
example, users can ask DAMOS to page out up to 100 MiB of memory regions
per second. Then DAMOS pages out regions that are not accessed for a
longer time (colder) first under the limit. This allows users to set the
target access pattern a bit naive with wider ranges, and focus on tuning
only one parameter, the quota. In other words, the number of parameters
to tune can be reduced from six to one.
Still, however, the optimum value for the quota depends on the system and
the workloads' characteristics, so not that simple. The number of
parameters to tune can also increase again if the user needs to run
multiple schemes.
Aim-oriented Feedback-driven DAMOS Aggressiveness Auto Tuning
=============================================================
Users would use DAMOS since they want to achieve something with it. They
will likely have measurable metrics representing the achievement and the
target number of the metric like SLO, and continuously measure that
anyway. While the additional cost of getting the information is nearly
zero, it could be useful for DAMOS to understand how appropriate its
current aggressiveness is set, and adjust it on its own to make the metric
value more close to the target.
Based on this idea, we introduce a new way of tuning DAMOS with nearly
zero additional effort, namely Aim-oriented Feedback-driven DAMOS
Aggressiveness Auto Tuning. It asks users to provide feedback
representing how well DAMOS is doing relative to the users' aim. Then
DAMOS adjusts its aggressiveness, specifically the quota that provides
the best effort result under the limit, based on the current level of
the aggressiveness and the users' feedback.
Implementation
==============
The implementation asks users to represent the feedback with score
numbers. The scores could be anything including user-space specific
metrics including latency and throughput of special user-space workloads,
and system metrics including free memory ratio, memory pressure stall time
(PSI), and active to inactive LRU lists size ratio. The feedback scores
and the aggressiveness of the given DAMOS scheme are assumed to be
positively proportional, though. Selecting metrics of the assumption is
the users' responsibility.
The core logic uses the below simple feedback loop algorithm to calculate
the next aggressiveness level of the scheme from the current
aggressiveness level and the current feedback (target_score and
current_score). It calculates the compensation for next aggressiveness as
a proportion of current aggressiveness and distance to the target score.
As a result, it arrives at the near-goal state in a short time using big
steps when it's far from the goal, but avoids making unnecessarily radical
changes that could turn out to be a bad decision using small steps when
its near to the goal.
f(n) = max(1, f(n - 1) * ((target_score - current_score) / target_score + 1))
Note that the compensation value becomes negative when it's over
achieving the goal. That's why the feedback metric and the
aggressiveness of the scheme should be positively proportional. The
distance-adaptive speed manipulation is simply applied.
Example Use Cases
=================
If users want to reduce the memory footprint of the system as much as
possible as long as the time spent for handling the resulting memory
pressure is within a threshold, they could use DAMOS scheme that reclaims
cold memory regions aiming for a little level of memory pressure stall
time.
If users want the active/inactive LRU lists well balanced to reduce the
performance impact due to possible future memory pressure, they could use
two schemes. The first one would be set to locate hot pages in the active
LRU list, aiming for a specific active-to-inactive LRU list size ratio,
say, 70%. The second one would be to locate cold pages in the inactive
LRU list, aiming for a specific inactive-to-active LRU list size ratio,
say, 30%. Then, DAMOS will balance the two schemes based on the goal and
feedback.
This aim-oriented auto tuning could also be useful for general
balancing-required access aware system operations such as system memory
auto scaling[3] and tiered memory management[4]. These two example usages
are not what current DAMOS implementation is already supporting, but
require additional DAMOS action developments, though.
Evaluation: subtle memory pressure aiming proactive reclamation
===============================================================
To show if the implementation works as expected, we prepare four different
system configurations on AWS i3.metal instances. The first setup
(original) runs the workload without any DAMOS scheme. The second setup
(not-tuned) runs the workload with a virtual address space-based proactive
reclamation scheme that pages out memory regions that are not accessed for
five seconds or more. The third setup (offline-tuned) runs the same
proactive reclamation DAMOS scheme, but after making it tuned for each
workload offline, using our previous user-space driven automatic tuning
approach, namely DAMOOS[1]. The fourth and final setup (AFDAA) runs the
scheme that is the same as that of 'not-tuned' setup, but aims to keep
0.5% of 'some' memory pressure stall time (PSI) for the last 10 seconds
using the aiming-oriented auto tuning.
For each setup, we run realistic workloads from PARSEC3 and SPLASH-2X
benchmark suites. For each run, we measure RSS and runtime of the
workload, and 'some' memory pressure stall time (PSI) of the system. We
repeat the runs five times and use averaged measurements.
For simple comparison of the results, we normalize the measurements to
those of 'original'. In the case of the PSI, though, the measurement for
'original' was zero, so we normalize the value to that of 'not-tuned'
scheme's result. The normalized results are shown below.
Not-tuned Offline-tuned AFDAA
RSS 0.622688178226118 0.787950678944904 0.740093483278979
runtime 1.11767826657912 1.0564674983585 1.0910833880499
PSI 1 0.727521443794069 0.308498846350299
The 'not-tuned' scheme achieves about 38.7% memory saving but incur about
11.7% runtime slowdown. The 'offline-tuned' scheme achieves about 22.2%
memory saving with about 5.5% runtime slowdown. It also achieves about
28.2% memory pressure stall time saving. AFDAA achieves about 26% memory
saving with about 9.1% runtime slowdown. It also achieves about 69.1%
memory pressure stall time saving. We repeat this test multiple times,
and get consistent results. AFDAA is now integrated in our daily DAMON
performance test setup.
Apparently the aggressiveness of 'AFDAA' setup is somewhere between those
of 'not-tuned' and 'offline-tuned' setup, since its memory saving and
runtime overhead are between those of the other two setups. Actually we
set the memory pressure stall time goal aiming for this middle
aggressiveness. The difference in the two metrics are not significant,
though. However, it shows significant saving of the memory pressure stall
time, which was the goal of the auto-tuning, over the two variants.
Hence, we conclude the automatic tuning is working as expected.
Please note that the AFDAA setup is only for the evaluation, and
therefore intentionally set a bit aggressive. It might not be
appropriate for production environments.
The test code is also available[2], so you could reproduce it on your
system and workloads.
Patches Sequence
================
The first four patches implement the core logic and user interfaces for
the auto tuning. The first patch implements the core logic for the auto
tuning, and the API for DAMOS users in the kernel space. The second
patch implements basic file operations of DAMON sysfs directories and
files that will be used for setting the goals and providing the
feedback. The third patch connects the quota goals files inputs to the
DAMOS core logic. Finally the fourth patch implements a dedicated DAMOS
sysfs command for efficiently committing the quota goals feedback.
Two patches for simple tests of the logic and interfaces follow. The
fifth patch implements the core logic unit test. The sixth patch
implements a selftest for the DAMON Sysfs interface for the goals.
Finally, three patches for documentation follows. The seventh patch
documents the design of the feature. The eighth patch updates the API
doc for the new sysfs files. The final eighth patch updates the usage
document for the features.
References
==========
[1] DAOS paper:
https://www.amazon.science/publications/daos-data-access-aware-operating-system
[2] Evaluation code:
https://github.com/damonitor/damon-tests/commit/3f884e61193f0166b8724554b6d06b0c449a712d
[3] Memory auto scaling RFC idea:
https://lore.kernel.org/damon/20231112195114.61474-1-sj@kernel.org/
[4] DAMON-based tiered memory management RFC idea:
https://lore.kernel.org/damon/20231112195602.61525-1-sj@kernel.org/
This patch (of 9)
Users can effectively control the upper-limit aggressiveness of DAMOS
schemes using the quota feature. The quota provides best result under the
limit by prioritizing regions based on the access pattern. That said,
finding the best value, which could depend on dynamic characteristics of
the system and the workloads, is still challenging.
Implement a simple feedback-driven tuning mechanism and use it for
automatic tuning of DAMOS quota. The implementation allows users to
provide the feedback by setting a feedback score returning callback
function. Then DAMOS periodically calls the function back and adjusts the
quota based on the return value of the callback and current quota value.
Note that the absolute-value based time/size quotas still work as the
maximum hard limits of the scheme's aggressiveness. The feedback-driven
auto-tuned quota is applied only if it is not exceeding the manually set
maximum limits. Same for the scheme-target access pattern and filters
like other features.
[sj@kernel.org: document get_score_arg field of struct damos_quota]
Link: https://lkml.kernel.org/r/20231204170106.60992-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Regions split function ('damon_split_region_at()') is called at the
beginning of an aggregation interval, and when DAMOS applying the actions
and charging quota. Because 'nr_accesses' fields of all regions are reset
at the beginning of each aggregation interval, and DAMOS was applying the
action at the end of each aggregation interval, there was no need to copy
the 'nr_accesses' field to the split-out region.
However, commit 42f994b71404 ("mm/damon/core: implement scheme-specific
apply interval") made DAMOS applies action on its own timing interval.
Hence, 'nr_accesses' should also copied to split-out regions, but the
commit didn't. Fix it by copying it.
Link: https://lkml.kernel.org/r/20231119171529.66863-1-sj@kernel.org
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The function '__damos_filter_out()' causes DAMON to always filter out
schemes whose filter type is anon or memcg if its matching value is set
to false.
This commit addresses the issue by ensuring that '__damos_filter_out()'
no longer applies to filters whose type is 'anon' or 'memcg'.
Link: https://lkml.kernel.org/r/1699594629-3816-1-git-send-email-hyeongtak.ji@gmail.com
Fixes: ab9bda001b681 ("mm/damon/core: introduce address range type damos filter")
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
"As usual, lots of singleton and doubleton patches all over the tree
and there's little I can say which isn't in the individual changelogs.
The lengthier patch series are
- 'kdump: use generic functions to simplify crashkernel reservation
in arch', from Baoquan He. This is mainly cleanups and
consolidation of the 'crashkernel=' kernel parameter handling
- After much discussion, David Laight's 'minmax: Relax type checks in
min() and max()' is here. Hopefully reduces some typecasting and
the use of min_t() and max_t()
- A group of patches from Oleg Nesterov which clean up and slightly
fix our handling of reads from /proc/PID/task/... and which remove
task_struct.thread_group"
* tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits)
scripts/gdb/vmalloc: disable on no-MMU
scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n
.mailmap: add address mapping for Tomeu Vizoso
mailmap: update email address for Claudiu Beznea
tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions
.mailmap: map Benjamin Poirier's address
scripts/gdb: add lx_current support for riscv
ocfs2: fix a spelling typo in comment
proc: test ProtectionKey in proc-empty-vm test
proc: fix proc-empty-vm test with vsyscall
fs/proc/base.c: remove unneeded semicolon
do_io_accounting: use sig->stats_lock
do_io_accounting: use __for_each_thread()
ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error()
ocfs2: fix a typo in a comment
scripts/show_delta: add __main__ judgement before main code
treewide: mark stuff as __ro_after_init
fs: ocfs2: check status values
proc: test /proc/${pid}/statm
compiler.h: move __is_constexpr() to compiler.h
...
|
|
When calculating the pseudo-moving access rate, DAMON divides some values
by the maximum nr_accesses. However, due to the type of the related
variables, simple division-based calculation of the divisor can return
zero. As a result, divide-by-zero is possible. Fix it by using
damon_max_nr_accesses(), which handles the case.
Note that this is a fix for a commit that not in the mainline but mm
tree.
Link: https://lkml.kernel.org/r/20231019194924.100347-6-sj@kernel.org
Fixes: ace30fb21af5 ("mm/damon/core: use pseudo-moving sum for nr_accesses_bp")
Reported-by: Jakub Acs <acsjakub@amazon.de>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When monitoring attributes are changed, DAMON updates access rate of the
monitoring results accordingly. For that, it divides some values by the
maximum nr_accesses. However, due to the type of the related variables,
simple division-based calculation of the divisor can return zero. As a
result, divide-by-zero is possible. Fix it by using
damon_max_nr_accesses(), which handles the case.
Link: https://lkml.kernel.org/r/20231019194924.100347-3-sj@kernel.org
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> [6.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
si_meminfo() will read and assign more info not just free/ram pages. For
just DAMOS_WMARK_FREE_MEM_RATE use, only get free and ram pages is ok to
save cpu.
Link: https://lkml.kernel.org/r/20230920015727.4482-1-link@vivo.com
Signed-off-by: Huan Yang <link@vivo.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add a kthread_stop_put() helper that stops a thread and puts its task
struct. Use it to replace the various instances of kthread_stop()
followed by put_task_struct().
Remove the kthread_stop_put() macro in usbip that is similar but doesn't
return the result of kthread_stop().
[agruenba@redhat.com: fix kerneldoc comment]
Link: https://lkml.kernel.org/r/20230911111730.2565537-1-agruenba@redhat.com
[akpm@linux-foundation.org: document kthread_stop_put()'s argument]
Link: https://lkml.kernel.org/r/20230907234048.2499820-1-agruenba@redhat.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
