damon_sample_mtier 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/20250916033511.116366-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_sample_prcl 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/20250916033511.116366-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_sample_wsse 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/20250916033511.116366-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "samples/damon: fix boot time enable handling fixup merge
mistakes".
First three patches of the patch series "mm/damon: fix misc bugs in DAMON
modules" [1] were trying to fix boot time DAMON sample modules enabling
issues. The issues are the modules can crash if those are enabled before
DAMON is enabled, like using boot time parameter options. The three
patches were fixing the issues by avoiding starting DAMON before the
module initialization phase.
However, probably by a mistake during a merge, only half of the change is
merged, and the part for avoiding the starting of DAMON before the module
initialized is missed. So the problem is not solved and thus the modules
can still crash if enabled before DAMON is initialized. Fix those by
applying the unmerged parts again.
Note that the broken commits are merged into 6.17-rc1, but also backported
to relevant stable kernels. So this series also needs to be merged into
the stable kernels. Hence Cc-ing stable@.
This patch (of 3):
Commit 0ed1165c37 ("samples/damon/wsse: fix boot time enable handling")
is somehow incompletely applying the origin patch [2]. It is missing the
part that avoids starting DAMON before module initialization. Probably a
mistake during a merge has happened. Fix it by applying the missed part
again.
Link: https://lkml.kernel.org/r/20250909022238.2989-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250909022238.2989-2-sj@kernel.org
Link: https://lkml.kernel.org/r/20250706193207.39810-1-sj@kernel.org [1]
Link: https://lore.kernel.org/20250706193207.39810-2-sj@kernel.org [2]
Fixes: 0ed1165c37 ("samples/damon/wsse: fix boot time enable handling")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Implement cleanup_target() callback for [f]vaddr, which calls put_pid()
for each target that will be destroyed. Also remove redundant put_pid()
calls in core, sysfs and sample modules, which were required to be done
redundantly due to the lack of such self cleanup in vaddr.
Link: https://lkml.kernel.org/r/20250712195016.151108-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch adds a new knob `detect_node_addresses`, which determines
whether the physical address range is set manually using the existing
knobs or automatically by the mtier module. When `detect_node_addresses`
set to 'Y', mtier automatically converts node0 and node1 to their physical
addresses. If set to 'N', it uses the existing 'node#_start_addr' and
'node#_end_addr' to define regions as before.
Link: https://lkml.kernel.org/r/20250707235919.513-1-yunjeong.mun@sk.com
Signed-off-by: Yunjeong Mun <yunjeong.mun@sk.com>
Suggested-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The damon_{lru_sort,reclaim,stat} kernel modules use "enabled" parameter
knobs as follows.
/sys/module/damon_lru_sort/parameters/enabled
/sys/module/damon_reclaim/parameters/enabled
/sys/module/damon_stat/parameters/enabled
However, other sample modules of damon use "enable" parameter knobs so
it'd be better to rename them from "enable" to "enabled" to keep the
consistency with other damon modules.
Before:
/sys/module/damon_sample_wsse/parameters/enable
/sys/module/damon_sample_prcl/parameters/enable
/sys/module/damon_sample_mtier/parameters/enable
After:
/sys/module/damon_sample_wsse/parameters/enabled
/sys/module/damon_sample_prcl/parameters/enabled
/sys/module/damon_sample_mtier/parameters/enabled
There is no functional changes in this patch.
Link: https://lkml.kernel.org/r/20250707024548.1964-1-honggyu.kim@sk.com
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 sample module, mtier has its name 'mtier'. It could conflict with
future modules, and not very easy to identify it by name. Use a prefix,
"damon_sample_" for the name.
Note that this could break users if they depend on the old name. But it
is just a sample, so no such usage is expected, or known. Even if such
usage exists, updating it for the new name should be straightforward.
Link: https://lkml.kernel.org/r/20250705175000.56259-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON sample module, prcl has its name 'prcl'. It could conflict with
future modules, and not very easy to identify it by name. Use a prefix,
"damon_sample_" for the name.
Note that this could break users if they depend on the old name. But it
is just a sample, so no such usage is expected, or known. Even if such
usage exists, updating it for the new name should be straightforward.
Link: https://lkml.kernel.org/r/20250705175000.56259-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: misc cleanups".
Yet another round of miscellaneous DAMON cleanups.
This patch (of 6):
DAMON sample module, wsse has its name 'wsse'. It could conflict with
future modules, and not very easy to identify it by name. Use a prefix,
"damon_sample_" for the name.
Note that this could break users if they depend on the old name. But it
is just a sample, so no such usage is expected, or known. Even if such
usage exists, updating it for the new name should be straightforward.
Link: https://lkml.kernel.org/r/20250705175000.56259-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250705175000.56259-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If 'enable' parameter of the 'mtier' DAMON sample module is set at boot
time via the kernel command line, memory allocation is tried before the
slab is initialized. As a result kernel NULL pointer dereference BUG can
happen. Fix it by checking the initialization status.
Link: https://lkml.kernel.org/r/20250706193207.39810-4-sj@kernel.org
Fixes: 82a08bde3c ("samples/damon: implement a DAMON module for memory tiering")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If 'enable' parameter of the 'prcl' DAMON sample module is set at boot
time via the kernel command line, memory allocation is tried before the
slab is initialized. As a result kernel NULL pointer dereference BUG can
happen. Fix it by checking the initialization status.
Link: https://lkml.kernel.org/r/20250706193207.39810-3-sj@kernel.org
Fixes: 2aca254620 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: fix misc bugs in DAMON modules".
From manual code review, I found below bugs in DAMON modules.
DAMON sample modules crash if those are enabled at boot time, via kernel
command line. A similar issue was found and fixed on DAMON non-sample
modules in the past, but we didn't check that for sample modules.
DAMON non-sample modules are not setting 'enabled' parameters accordingly
when real enabling is failed. Honggyu found and fixed[1] this type of
bugs in DAMON sample modules, and my inspection was motivated by the great
work. Kudos to Honggyu.
Finally, DAMON_RECLIAM is mistakenly losing scheme internal status due to
misuse of damon_commit_ctx(). DAMON_LRU_SORT has a similar misuse, but
fortunately it is not causing real status loss.
Fix the bugs. Since these are similar patterns of bugs that were found in
the past, it would be better to add tests or refactor the code, in future.
This patch (of 6):
If 'enable' parameter of the 'wsse' DAMON sample module is set at boot
time via the kernel command line, memory allocation is tried before the
slab is initialized. As a result kernel NULL pointer dereference BUG can
happen. Fix it by checking the initialization status.
Link: https://lkml.kernel.org/r/20250706193207.39810-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250706193207.39810-2-sj@kernel.org
Link: https://lore.kernel.org/20250702000205.1921-1-honggyu.kim@sk.com [1]
Fixes: b757c6cfc6 ("samples/damon/wsse: start and stop DAMON as the user requests")
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: fix divide by zero and its samples", v3.
This series includes fixes against damon and its samples to make it safer
when damon sample starting fails.
It includes the following changes.
- fix unexpected divide by zero crash for zero size regions
- fix bugs for damon samples in case of start failures
This patch (of 4):
The damon_sample_prcl_start() can fail so we must reset the "enable"
parameter to "false" again for proper rollback.
In such cases, setting Y to "enable" then N triggers the following crash
because damon sample start failed but the "enable" stays as Y.
[ 2441.419649] damon_sample_prcl: start
[ 2454.146817] damon_sample_prcl: stop
[ 2454.146862] ------------[ cut here ]------------
[ 2454.146865] kernel BUG at mm/slub.c:546!
[ 2454.148183] Oops: invalid opcode: 0000 [#1] SMP NOPTI
...
[ 2454.167555] Call Trace:
[ 2454.167822] <TASK>
[ 2454.168061] damon_destroy_ctx+0x78/0x140
[ 2454.168454] damon_sample_prcl_enable_store+0x8d/0xd0
[ 2454.168932] param_attr_store+0xa1/0x120
[ 2454.169315] module_attr_store+0x20/0x50
[ 2454.169695] sysfs_kf_write+0x72/0x90
[ 2454.170065] kernfs_fop_write_iter+0x150/0x1e0
[ 2454.170491] vfs_write+0x315/0x440
[ 2454.170833] ksys_write+0x69/0xf0
[ 2454.171162] __x64_sys_write+0x19/0x30
[ 2454.171525] x64_sys_call+0x18b2/0x2700
[ 2454.171900] do_syscall_64+0x7f/0x680
[ 2454.172258] ? exit_to_user_mode_loop+0xf6/0x180
[ 2454.172694] ? clear_bhb_loop+0x30/0x80
[ 2454.173067] ? clear_bhb_loop+0x30/0x80
[ 2454.173439] entry_SYSCALL_64_after_hwframe+0x76/0x7e
Link: https://lkml.kernel.org/r/20250702000205.1921-1-honggyu.kim@sk.com
Link: https://lkml.kernel.org/r/20250702000205.1921-2-honggyu.kim@sk.com
Fixes: 2aca254620 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON is not only for monitoring of access patterns, but also for
access-aware system operations. For the system operations, DAMON provides
a feature called DAMOS (Data Access Monitoring-based Operation Schemes).
There is no sample API usage of DAMOS, though. Copy the working set size
estimation sample modules with changed names of the module and symbols, to
use it as a skeleton for a sample module showing the DAMOS API usage. The
following commit will make it proactively reclaim cold memory of the given
process, using DAMOS.
Link: https://lkml.kernel.org/r/20241210215030.85675-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Implement the DAMON-based working set size estimation logic. The logic
iterates memory regions in DAMON-generated access pattern snapshot for
every aggregation interval and get the total sum of the size of any region
having one or higher 'nr_accesses' count. That is, it assumes any region
having one or higher 'nr_accesses' to be a part of the working set. The
estimated value is reported to the user by printing it to the kernel log.
Link: https://lkml.kernel.org/r/20241210215030.85675-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Start running DAMON to monitor accesses of a process that the user
specified via 'target_pid' parameter, when 'y' is passed to 'enable'
parameter. Stop running DAMON when 'n' is passed to 'enable' parameter.
Estimating the working set size from DAMON's monitoring results and
reporting it to the user will be implemented by the following commit.
Link: https://lkml.kernel.org/r/20241210215030.85675-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: add sample modules".
Implement a proactive cold memory regions reclaiming logic of prcl sample
module using DAMOS. The logic treats memory regions that not accessed at
all for five or more seconds as cold, and reclaim those as soon as found.
This patch (of 5):
Add a skeleton for a sample DAMON static module that can be used for
estimating working set size of a given process. Note that it is a static
module since DAMON is not exporting symbols to loadable modules for now.
It exposes two module parameters, namely 'pid' and 'enable'. 'pid' will
specify the process that the module will estimate the working set size of.
'enable' will receive whether to start or stop the estimation. Because
this is just a skeleton, the parameters do nothing, though. The
functionalities will be implemented by following commits.
Link: https://lkml.kernel.org/r/20241210215030.85675-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20241210215030.85675-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
