kernel.git/samples/damon/prcl.c, branch linux-6.16.y

samples/damon/prcl: avoid starting DAMON before initialization

2025-09-25T09:16:54Z

commit e6b733ca2f99e968d696c2e812c8eb8e090bf37b upstream. Commit 2780505ec2b4 ("samples/damon/prcl: fix boot time enable crash") is somehow incompletely applying the origin patch [1]. 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/20250909022238.2989-3-sj@kernel.org Link: https://lore.kernel.org/20250706193207.39810-3-sj@kernel.org [1] Fixes: 2780505ec2b4 ("samples/damon/prcl: fix boot time enable crash") Signed-off-by: SeongJae Park Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

samples/damon: change enable parameters to enabled

2025-09-25T09:16:54Z

[ Upstream commit 793020545cea0c9e2a79de6ad5c9746ec4f5bd7e ] 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 Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: c62cff40481c ("samples/damon/mtier: avoid starting DAMON before initialization") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

samples/damon/prcl: fix boot time enable crash

2025-09-25T09:16:53Z

[ Upstream commit 2780505ec2b42c07853b34640bc63279ac2bb53b ] 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: 2aca254620a8 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: c62cff40481c ("samples/damon/mtier: avoid starting DAMON before initialization") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

samples/damon: fix damon sample prcl for start failure

2025-07-10T04:07:54Z

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] [ 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: 2aca254620a8 ("samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation") Signed-off-by: Honggyu Kim Reviewed-by: SeongJae Park Cc: Signed-off-by: Andrew Morton

samples/damon/prcl: fix a comment typo

2025-05-12T00:48:31Z

This patch just fixes a typo in the comment. Link: https://lkml.kernel.org/r/20250411073800.1444481-1-lienze@kylinos.cn Signed-off-by: Enze Li Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon/prcl: implement schemes setup

2025-01-14T06:40:57Z

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. Link: https://lkml.kernel.org/r/20241210215030.85675-6-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation

2025-01-14T06:40:57Z

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 Signed-off-by: Andrew Morton