DAMON_LRU_SORT updates 'enabled' and 'kdamond_pid' parameter values, which
represents the running status of its kdamond, when the user explicitly
requests start/stop of the kdamond. The kdamond can, however, be stopped
in events other than the explicit user request in the following three
events.
1. ctx->regions_score_histogram allocation failure at beginning of the
execution,
2. damon_commit_ctx() failure due to invalid user input, and
3. damon_commit_ctx() failure due to its internal allocation failures.
Hence, if the kdamond is stopped by the above three events, the values of
the status parameters can be stale. Users could show the stale values and
be confused. This is already bad, but the real consequence is worse.
DAMON_LRU_SORT avoids unnecessary damon_start() and damon_stop() calls
based on the 'enabled' parameter value. And the update of 'enabled'
parameter value depends on the damon_start() and damon_stop() call
results. Hence, once the kdamond has stopped by the unintentional events,
the user cannot restart the kdamond before the system reboot. For
example, the issue can be reproduced via below steps.
# cd /sys/module/damon_lru_sort/parameters
#
# # start DAMON_LRU_SORT
# echo Y > enabled
# ps -ef | grep kdamond
root 806 2 0 17:53 ? 00:00:00 [kdamond.0]
root 808 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # commit wrong input to stop kdamond withou explicit stop request
# echo 3 > addr_unit
# echo Y > commit_inputs
bash: echo: write error: Invalid argument
#
# # confirm kdamond is stopped
# ps -ef | grep kdamond
root 811 803 0 17:53 pts/4 00:00:00 grep kdamond
#
# # users casn now show stable status
# cat enabled
Y
# cat kdamond_pid
806
#
# # even after fixing the wrong parameter,
# # kdamond cannot be restarted.
# echo 1 > addr_unit
# echo Y > enabled
# ps -ef | grep kdamond
root 815 803 0 17:54 pts/4 00:00:00 grep kdamond
The problem will only rarely happen in real and common setups for the
following reasons. The allocation failures are unlikely in such setups
since those allocations are arguably too small to fail. Also sane users
on real production environments may not commit wrong input parameters.
But once it happens, the consequence is quite bad. And the bug is a bug.
The issue stems from the fact that there are multiple events that can
change the status, and following all the events is challenging.
Dynamically detect and use the fresh status for the parameters when those
are requested.
Link: https://lore.kernel.org/20260419161003.79176-3-sj@kernel.org
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Co-developed-by: Liew Rui Yan <aethernet65535@gmail.com>
Signed-off-by: Liew Rui Yan <aethernet65535@gmail.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.0.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the past, damon_set_region_biggest_system_ram_default(), which is the
core function for setting the default monitoring target region of
DAMON_LRU_SORT, didn't support addr_unit. Hence DAMON_LRU_SORT was
silently ignoring the user input for addr_unit when the user doesn't
explicitly set the monitoring target regions, and therefore the default
target region is being used. No real problem from that ignorance was
reported so far. But, the implicit rule is only making things confusing.
Also, the default target region setup function is updated to support
addr_unit. Hence there is no reason to keep ignoring it. Respect the
user-passed addr_unit for the default target monitoring region use case.
Link: https://lkml.kernel.org/r/20260311052927.93921-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Yang yingliang <yangyingliang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_find_biggest_system_ram() was not supporting addr_unit in the past.
Hence, its caller, damon_set_region_biggest_system_ram_default(), was also
not supporting addr_unit. The previous commit has updated the inner
function to support addr_unit. There is no more reason to not support
addr_unit on damon_set_region_biggest_system_ram_default(). Rather, it
makes unnecessary inconsistency on support of addr_unit. Update it to
receive addr_unit and handle it inside.
Link: https://lkml.kernel.org/r/20260311052927.93921-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Yang yingliang <yangyingliang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
'min_sz_region' field of 'struct damon_ctx' represents the minimum size of
each DAMON region for the context. 'struct damos_access_pattern' has a
field of the same name. It confuses readers and makes 'grep' less optimal
for them. Rename it to 'min_region_sz'.
Link: https://lkml.kernel.org/r/20260117175256.82826-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The macro is for the default minimum size of each DAMON region. There was
a case that a reader was confused if it is the minimum number of total
DAMON regions, which is set on damon_attrs->min_nr_regions. Make the name
more explicit.
Link: https://lkml.kernel.org/r/20260117175256.82826-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT directly uses damon_ctx->kdamond field with manual
synchronization using damon_ctx->kdamond_lock, to get the pid of the
kdamond. Use a new dedicated function for the purpose, namely
damon_kdamond_pid(), since that doesn't require manual and error-prone
synchronization.
Link: https://lkml.kernel.org/r/20260115152047.68415-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON monitoring intervals tuning was crucial for every DAMON use case.
Now there are a tuning guideline and an automated intervals tuning
feature. DAMON_LRU_SORT is still using manual control of intervals. Add
a module parameter for utilizing the auto-tuning feature with a suggested
auto-tuning parameters.
Link: https://lkml.kernel.org/r/20260113152717.70459-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Acked-by: wang lian <lianux.mm@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Doing DAMOS_LRU_[DE]PRIO with DAMOS_QUOTA_[IN]ACTIVE_MEM_BP based quota
auto-tuning can be easy and intuitive, compared to the manual
[de]prioritization target access pattern thresholds tuning. For example,
users can ask DAMON to "find hot/cold pages and activate/deactivate those
aiming 50:50 active:inactive memory size." But DAMON_LRU_SORT has no
interface to do that. Add a module parameter for setting the target
ratio.
[sj@kernel.org: add inactive mem ratio quota goal to cold_scheme]
Link: https://lkml.kernel.org/r/20260114055308.79884-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260113152717.70459-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON monitors access patterns at the region level, and hence there could
be some page level mismatches. A few hot pages could be located in cold
regions, and vice versa. Young page filters can be useful for doing
additional page level access checks before applying some DAMOS action.
DAMON_LRU_SORT is not using young page filters, though. Add a parameter
for using it.
Link: https://lkml.kernel.org/r/20260113152717.70459-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT is doing under-quota access pattern based regions
prioritization using only access frequency. Age of regions is another
useful information for distinguishing hot and cold regions. Use it for
prioritization, too.
Link: https://lkml.kernel.org/r/20260113152717.70459-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Correct minor spelling mistakes in several files under mm/damon. No
functional changes.
Link: https://lkml.kernel.org/r/20251217181216.47576-1-klourencodev@gmail.com
Signed-off-by: Kevin Lourenco <klourencodev@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: fixes for address alignment issues in
DAMON_LRU_SORT and DAMON_RECLAIM", v2.
In DAMON_LRU_SORT and DAMON_RECLAIM, damon_set_regions() will apply
DAMON_MIN_REGION as the core address alignment, and the monitoring target
address ranges would be aligned on DAMON_MIN_REGION * addr_unit. When
users 1) set addr_unit to a value larger than 1, and 2) set the monitoring
target address range as not aligned on DAMON_MIN_REGION * addr_unit, it
will cause DAMON_LRU_SORT and DAMON_RECLAIM to operate on unexpectedly
large physical address ranges.
For example, if the user sets the monitoring target address range to [4,
8) and addr_unit as 1024, the aimed monitoring target address range is [4
KiB, 8 KiB). Assuming DAMON_MIN_REGION is 4096, so resulting target
address range will be [0, 4096) in the DAMON core layer address system,
and [0, 4 MiB) in the physical address space, which is an unexpected
range.
To fix the issue, add a min_sz_region parameter to
damon_set_region_biggest_system_ram_default() and use it when calling
damon_set_regions(), replacing the direct use of DAMON_MIN_REGION.
This patch (of 2):
In DAMON_LRU_SORT, damon_set_regions() will apply DAMON_MIN_REGION as the
core address alignment, and the monitoring target address ranges would be
aligned on DAMON_MIN_REGION * addr_unit. When users 1) set addr_unit to a
value larger than 1, and 2) set the monitoring target address range as not
aligned on DAMON_MIN_REGION * addr_unit, it will cause DAMON_LRU_SORT to
operate on unexpectedly large physical address ranges.
For example, if the user sets the monitoring target address range to [4,
8) and addr_unit as 1024, the aimed monitoring target address range is [4
KiB, 8 KiB). Assuming DAMON_MIN_REGION is 4096, so resulting target
address range will be [0, 4096) in the DAMON core layer address system,
and [0, 4 MiB) in the physical address space, which is an unexpected
range.
To fix the issue, add a min_sz_region parameter to
damon_set_region_biggest_system_ram_default() and use it when calling
damon_set_regions(), replacing the direct use of DAMON_MIN_REGION.
Link: https://lkml.kernel.org/r/20251020130125.2875164-1-yanquanmin1@huawei.com
Link: https://lkml.kernel.org/r/20251020130125.2875164-2-yanquanmin1@huawei.com
Fixes: 2e0fe9245d ("mm/damon/lru_sort: support addr_unit for DAMON_LRU_SORT")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT is assuming DAMON is ready to use in module_init time, and
uses its own hack to see if it is the time. Use damon_initialized(),
which is a way for seeing if DAMON is ready to be used that is more
reliable and better to maintain instead of the hack.
Link: https://lkml.kernel.org/r/20250916033511.116366-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_apply_parameters() allocates a new DAMON context, stages
user-specified DAMON parameters on it, and commits to running DAMON
context at once, using damon_commit_ctx(). The code is, however, directly
updating the monitoring attributes of the running context. And the
attributes are over-written by later damon_commit_ctx() call. This means
that the monitoring attributes parameters are not really working. Fix the
wrong use of the parameter context.
Link: https://lkml.kernel.org/r/20250916031549.115326-1-sj@kernel.org
Fixes: a309694364 ("mm/damon/lru_sort: use damon_commit_ctx()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: <stable@vger.kernel.org> [6.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: add addr_unit for DAMON_LRU_SORT and
DAMON_RECLAIM".
In DAMON_LRU_SORT and DAMON_RECLAIM, damon_ctx is independent of the core.
Add addr_unit to these modules to support systems like ARM32 with LPAE.
This patch (of 2):
Implement a sysfs file to expose addr_unit for DAMON_LRU_SORT users.
During parameter application, use the configured addr_unit parameter to
perform the necessary initialization. Similar to the core layer, prevent
setting addr_unit to zero.
It is worth noting that when monitor_region_start and monitor_region_end
are unset (i.e., 0), their values will later be set to biggest_system_ram.
At that point, addr_unit may not be the default value 1. Although we
could divide the biggest_system_ram value by addr_unit, changing addr_unit
without setting monitor_region_start/end should be considered a user
misoperation. And biggest_system_ram is only within the 0~ULONG_MAX
range, system can clearly work correctly with addr_unit=1. Therefore, if
monitor_region_start/end are unset, always silently reset addr_unit to 1.
Link: https://lkml.kernel.org/r/20250910113221.1065764-1-yanquanmin1@huawei.com
Link: https://lkml.kernel.org/r/20250910113221.1065764-2-yanquanmin1@huawei.com
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: avoid divide-by-zero in DAMON module's parameters
application".
DAMON's RECLAIM and LRU_SORT modules perform no validation on
user-configured parameters during application, which may lead to
division-by-zero errors.
Avoid the divide-by-zero by adding validation checks when DAMON modules
attempt to apply the parameters.
This patch (of 2):
During the calculation of 'hot_thres' and 'cold_thres', either
'sample_interval' or 'aggr_interval' is used as the divisor, which may
lead to division-by-zero errors. Fix it by directly returning -EINVAL
when such a case occurs. Additionally, since 'aggr_interval' is already
required to be set no smaller than 'sample_interval' in damon_set_attrs(),
only the case where 'sample_interval' is zero needs to be checked.
Link: https://lkml.kernel.org/r/20250827115858.1186261-2-yanquanmin1@huawei.com
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org> [6.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT uses damon_callback for periodically reading and writing
DAMON internal data and parameters. Use its alternative, damon_call()
repeat mode.
Link: https://lkml.kernel.org/r/20250712195016.151108-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When the startup fails, 'enabled' parameter is not reset. As a result,
users show the parameter 'Y' while it is not really working. Fix it by
resetting 'enabled' to 'false' when the work is failed.
Link: https://lkml.kernel.org/r/20250706193207.39810-6-sj@kernel.org
Fixes: 7a034fbba3 ("mm/damon/lru_sort: enable and disable synchronously")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT contains code for handling of online DAMON parameters
update edge cases. It is no more necessary since damon_commit_ctx() takes
care of the cases. Remove the unnecessary code.
Link: https://lkml.kernel.org/r/20240618181809.82078-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT manually manipulates the DAMON context struct for online
parameters update. Since the struct contains not only input parameters
but also internal status and operation results, it is not that simple.
Indeed, we found and fixed a few bugs in the code. Now DAMON core layer
provides a function for the usage, namely damon_commit_ctx(). Replace the
manual manipulation logic with the function. The core layer function
could have its own bugs, but this change removes a source of bugs.
Link: https://lkml.kernel.org/r/20240618181809.82078-12-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>
For online parameters change, DAMON_LRU_SORT creates new schemes based on
latest values of the parameters and replaces the old schemes with the new
one. When creating it, the internal status of the quotas of the old
schemes is not preserved. As a result, charging of the quota starts from
zero after the online tuning. The data that collected to estimate the
throughput of the scheme's action is also reset, and therefore the
estimation should start from the scratch again. Because the throughput
estimation is being used to convert the time quota to the effective size
quota, this could result in temporal time quota inaccuracy. It would be
recovered over time, though. In short, the quota accuracy could be
temporarily degraded after online parameters update.
Fix the problem by checking the case and copying the internal fields for
the status.
Link: https://lkml.kernel.org/r/20240216194025.9207-3-sj@kernel.org
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [6.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When calculating the hotness threshold for lru_prio scheme of
DAMON_LRU_SORT, the module 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/20231019194924.100347-5-sj@kernel.org
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> [6.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON-based operation schemes are applied for every aggregation interval.
That was mainly because schemes were using nr_accesses, which be complete
to be used for every aggregation interval. However, the schemes are now
using nr_accesses_bp, which is updated for each sampling interval in a way
that reasonable to be used. Therefore, there is no reason to apply
schemes for each aggregation interval.
The unnecessary alignment with aggregation interval was also making some
use cases of DAMOS tricky. Quotas setting under long aggregation interval
is one such example. Suppose the aggregation interval is ten seconds, and
there is a scheme having CPU quota 100ms per 1s. The scheme will actually
uses 100ms per ten seconds, since it cannobe be applied before next
aggregation interval. The feature is working as intended, but the results
might not that intuitive for some users. This could be fixed by updating
the quota to 1s per 10s. But, in the case, the CPU usage of DAMOS could
look like spikes, and would actually make a bad effect to other
CPU-sensitive workloads.
Implement a dedicated timing interval for each DAMON-based operation
scheme, namely apply_interval. The interval will be sampling interval
aligned, and each scheme will be applied for its apply_interval. The
interval is set to 0 by default, and it means the scheme should use the
aggregation interval instead. This avoids old users getting any
behavioral difference.
Link: https://lkml.kernel.org/r/20230916020945.47296-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
strtobool() is the same as kstrtobool(). However, the latter is more used
within the kernel.
In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.
While at it, include the corresponding header file (<linux/kstrtox.h>)
Link: https://lkml.kernel.org/r/ed2b46489a513988688decb53850339cc228940c.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Writing a value to DAMON_RECLAIM's 'enabled' parameter turns on or off
DAMON in an ansychronous way. This means the parameter cannot be used to
read the current status of DAMON_RECLAIM. 'kdamond_pid' parameter should
be used instead for the purpose. The documentation is easy to be read as
it works in a synchronous way, so it is a little bit confusing. It also
makes the user space tooling dirty.
There's no real reason to have the asynchronous behavior, though. Simply
make the parameter works synchronously, rather than updating the document.
Link: https://lkml.kernel.org/r/20221025173650.90624-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Some headers that 'reclaim.c' and 'lru_sort.c' are including are
unnecessary now owing to previous cleanups and refactorings. Remove
those.
Link: https://lkml.kernel.org/r/20221026225943.100429-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM and DAMON_LRU_SORT has duplicated code for DAMON context and
target initializations. Deduplicate the part by implementing a function
for the initialization in 'modules-common.c' and using it.
Link: https://lkml.kernel.org/r/20221026225943.100429-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The bodies of damon_{reclaim,lru_sort}_apply_parameters() contain
duplicates. This commit adds a common function
damon_set_region_biggest_system_ram_default() to remove the duplicates.
Link: https://lkml.kernel.org/r/6329f00d.a70a0220.9bb29.3678SMTPIN_ADDED_BROKEN@mx.google.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no point in returning an int from damon_set_schemes(). It always
returns 0 which is meaningless for the caller, so change it to return void
directly.
Link: https://lkml.kernel.org/r/1663341635-12675-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_wmarks is only used in lru_sort.c now, change it to static.
Link: https://lkml.kernel.org/r/20220915021024.4177940-2-yangyingliang@huawei.com
Fixes: 189aa3d58206 ("mm/damon/lru_sort: use watermarks parameters generator macro")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In damon_lru_sort_new_hot_scheme() and damon_lru_sort_new_cold_scheme(),
they have so much in common, so we can combine them into a single
function, and we just need to distinguish their differences.
[yangyingliang@huawei.com: change damon_lru_sort_stub_pattern to static]
Link: https://lkml.kernel.org/r/20220917121228.1889699-1-yangyingliang@huawei.com
Link: https://lkml.kernel.org/r/20220915133041.71819-1-sj@kernel.org
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_new_{hot,cold}_scheme() have quite a lot of duplicates.
This commit factors out the duplicate to a separate function and use it
for reducing the duplicate.
Link: https://lkml.kernel.org/r/20220913174449.50645-23-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS watermarks using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-22-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS statistics using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-18-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS watermarks using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-14-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMON monitoring attributes using the generator macro to simplify the code
and reduce duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT receives monitoring attributes by parameters one by one to
separate variables, and then combines those into 'struct damon_attrs'.
This commit makes the module directly stores the parameter values to a
static 'struct damon_attrs' variable and use it to simplify the code.
Link: https://lkml.kernel.org/r/20220913174449.50645-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Number of parameters for 'damon_set_attrs()' is six. As it could be
confusing and verbose, this commit reduces the number by receiving single
pointer to a 'struct damon_attrs'.
Link: https://lkml.kernel.org/r/20220913174449.50645-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In damon_lru_sort_apply_parameters(), we can use damon_set_schemes() to
replace the way of creating the first 'scheme' in original code, this
makes the code look cleaner.
Link: https://lkml.kernel.org/r/20220911005917.835-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In lru_sort.c and reclaim.c, they are all defining get_monitoring_region()
function, there is no need to define it separately.
As 'get_monitoring_region()' is not a 'static' function anymore, we try to
use a prefix to distinguish with other functions, so there rename it to
'damon_find_biggest_system_ram'.
Link: https://lkml.kernel.org/r/20220909213606.136221-1-sj@kernel.org
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_new_scheme() has too many parameters, so introduce struct
damos_access_pattern to simplify it.
In additon, we can't use a bpf trace kprobe that has more than 5
parameters.
Link: https://lkml.kernel.org/r/20220908191443.129534-1-sj@kernel.org
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_init() returns an error when damon_select_ops() fails
without freeing 'ctx' which allocated before. This commit fixes the
potential memory leak by freeing 'ctx' under the situation.
Link: https://lkml.kernel.org/r/20220714170458.49727-1-sj@kernel.org
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Users can do data access-aware LRU-lists sorting using 'LRU_PRIO' and
'LRU_DEPRIO' DAMOS actions. However, finding best parameters including
the hotness/coldness thresholds, CPU quota, and watermarks could be
challenging for some users. To make the scheme easy to be used without
complex tuning for common situations, this commit implements a static
kernel module called 'DAMON_LRU_SORT' using the 'LRU_PRIO' and
'LRU_DEPRIO' DAMOS actions.
It proactively sorts LRU-lists using DAMON with conservatively chosen
default values of the parameters. That is, the module under its default
parameters will make no harm for common situations but provide some level
of efficiency improvements for systems having clear hot/cold access
pattern under a level of memory pressure while consuming only a limited
small portion of CPU time.
Link: https://lkml.kernel.org/r/20220613192301.8817-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
