| Message ID | 20210520075629.4332-1-sj38.park@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce Data Access MONitor (DAMON) | expand |
On Thu, 20 May 2021 07:56:16 +0000 SeongJae Park <sj38.park@gmail.com> wrote:
> Changes from Previous Version (v28)
Thanks for persisting with this.
I'd be interested in people's overall take on this work, please.
Mainly a high-level "should we merge this" view. Detailed review of
implementation and interface details can follow on in the usual fashion.
On Thu, May 20, 2021 at 3:34 PM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Thu, 20 May 2021 07:56:16 +0000 SeongJae Park <sj38.park@gmail.com> wrote: > > > Changes from Previous Version (v28) > > Thanks for persisting with this. > > I'd be interested in people's overall take on this work, please. > Mainly a high-level "should we merge this" view. Detailed review of > implementation and interface details can follow on in the usual fashion. I am planning to go over the whole series but first let me give my high-level view on the patch series. In my personal opinion, this patch series is in the state where we can merge this or at least add to the mm tree for further exposure. I have pushed SeongJae to keep the functionality to bare minimum in the first version and focus more on making the design extensible, so as more use-cases arise, the core can be extended accordingly. I am actually more interested in the followup of this work which would be extended to monitor cgroups for use-cases like hugepages, balancing hot/cold memory in memory tiers and hints for malloc implementations.
Hey Andrew, On Thu, 2021-05-20 at 15:34 -0700, Andrew Morton wrote: > Thanks for persisting with this. > > I'd be interested in people's overall take on this work, please. > Mainly a high-level "should we merge this" view. Detailed review of > implementation and interface details can follow on in the usual fashion. There are a few kernel developers at Amazon watching over this effort, and nudging it along. But more importantly, we're working with fleet owners operating large fleets to guide this effort. That makes the overall effort a 2-phase one: profiling first (which is what this patchset does), and then improving other things that use this profiling information for better system efficiencies. All that's primarily for use-cases internally right now. Once the base set of patches is upstream, we're going to work on all the various use- cases we've identified so far where this is going to be beneficial. Current internal uses are mainly around profiling. One example is mentioned by SeongJae in the cover letter's "Real-world User Story" section, where tuning page reclamation algorithms based on this profiling information is going to result in better efficiencies, and energy and cost reductions. Another interesting usecase that's developing is identifying free pages for reclamation and compaction based on this work. That's going to help live migration and memory overcommit scenarios for KVM guests. SJ is preparing to send out those patches to the lists as well. Thanks! Amit Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879
For patches 00 to 07,
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
For patches 08 to 10: Reviewed-by: Fernand Sieber <sieberf@amazon.com>
From: SeongJae Park <sjpark@amazon.de> Changes from Previous Version (v28) =================================== - Rebase on latest -mm tree (v5.13-rc1-mmots-2021-05-13-17-23) This version has no real change from the last version. I'm posting this after simple rebasing, since more than one month has passed since last version posting, and Shakeel also asked to do this. Also, the last version of this patchset has passed Amazon internal reviews and merged in two public Amazon Linux2 kernel trees that based on v5.4.y[1] and v5.10.y[2]. [1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon [2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon Introduction ============ DAMON is a data access monitoring framework for the Linux kernel. The core mechanisms of DAMON called 'region based sampling' and 'adaptive regions adjustment' (refer to 'mechanisms.rst' in the 11th patch of this patchset for the detail) make it - accurate (The monitored information is useful for DRAM level memory management. It might not appropriate for Cache-level accuracy, though.), - light-weight (The monitoring overhead is low enough to be applied online while making no impact on the performance of the target workloads.), and - scalable (the upper-bound of the instrumentation overhead is controllable regardless of the size of target workloads.). Using this framework, therefore, several memory management mechanisms such as reclamation and THP can be optimized to aware real data access patterns. Experimental access pattern aware memory management optimization works that incurring high instrumentation overhead will be able to have another try. Though DAMON is for kernel subsystems, it can be easily exposed to the user space by writing a DAMON-wrapper kernel subsystem. Then, user space users who have some special workloads will be able to write personalized tools or applications for deeper understanding and specialized optimizations of their systems. DAMON is also merged in two public Amazon Linux kernel trees that based on v5.4.y[1] and v5.10.y[2]. [1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon [2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon Long-term Plan -------------- DAMON is a part of a project called Data Access-aware Operating System (DAOS). As the name implies, I want to improve the performance and efficiency of systems using fine-grained data access patterns. The optimizations are for both kernel and user spaces. I will therefore modify or create kernel subsystems, export some of those to user space and implement user space library / tools. Below shows the layers and components for the project. --------------------------------------------------------------------------- Primitives: PTE Accessed bit, PG_idle, rmap, (Intel CMT), ... Framework: DAMON Features: DAMOS, virtual addr, physical addr, ... Applications: DAMON-debugfs, (DARC), ... ^^^^^^^^^^^^^^^^^^^^^^^ KERNEL SPACE ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Raw Interface: debugfs, (sysfs), (damonfs), tracepoints, (sys_damon), ... vvvvvvvvvvvvvvvvvvvvvvv USER SPACE vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv Library: (libdamon), ... Tools: DAMO, (perf), ... --------------------------------------------------------------------------- The components in parentheses or marked as '...' are not implemented yet but in the future plan. IOW, those are the TODO tasks of DAOS project. For more detail, please refer to the plans: https://lore.kernel.org/linux-mm/20201202082731.24828-1-sjpark@amazon.com/ Evaluations =========== We evaluated DAMON's overhead, monitoring quality and usefulness using 24 realistic workloads on my QEMU/KVM based virtual machine running a kernel that v24 DAMON patchset is applied. DAMON is lightweight. It increases system memory usage by 0.39% and slows target workloads down by 1.16%. DAMON is accurate and useful for memory management optimizations. An experimental DAMON-based operation scheme for THP, namely 'ethp', removes 76.15% of THP memory overheads while preserving 51.25% of THP speedup. Another experimental DAMON-based 'proactive reclamation' implementation, 'prcl', reduces 93.38% of residential sets and 23.63% of system memory footprint while incurring only 1.22% runtime overhead in the best case (parsec3/freqmine). NOTE that the experimental THP optimization and proactive reclamation are not for production but only for proof of concepts. Please refer to the official document[1] or "Documentation/admin-guide/mm: Add a document for DAMON" patch in this patchset for detailed evaluation setup and results. [1] https://damonitor.github.io/doc/html/latest-damon/admin-guide/mm/damon/eval.html Real-world User Story ===================== In summary, DAMON has used on production systems and proved its usefulness. DAMON as a profiler ------------------- We analyzed characteristics of a large scale production systems of our customers using DAMON. The systems utilize 70GB DRAM and 36 CPUs. From this, we were able to find interesting things below. There were obviously different access pattern under idle workload and active workload. Under the idle workload, it accessed large memory regions with low frequency, while the active workload accessed small memory regions with high freuqnecy. DAMON found a 7GB memory region that showing obviously high access frequency under the active workload. We believe this is the performance-effective working set and need to be protected. There was a 4KB memory region that showing highest access frequency under not only active but also idle workloads. We think this must be a hottest code section like thing that should never be paged out. For this analysis, DAMON used only 0.3-1% of single CPU time. Because we used recording-based analysis, it consumed about 3-12 MB of disk space per 20 minutes. This is only small amount of disk space, but we can further reduce the disk usage by using non-recording-based DAMON features. I'd like to argue that only DAMON can do such detailed analysis (finding 4KB highest region in 70GB memory) with the light overhead. DAMON as a system optimization tool ----------------------------------- We also found below potential performance problems on the systems and made DAMON-based solutions. The system doesn't want to make the workload suffer from the page reclamation and thus it utilizes enough DRAM but no swap device. However, we found the system is actively reclaiming file-backed pages, because the system has intensive file IO. The file IO turned out to be not performance critical for the workload, but the customer wanted to ensure performance critical file-backed pages like code section to not mistakenly be evicted. Using direct IO should or `mlock()` would be a straightforward solution, but modifying the user space code is not easy for the customer. Alternatively, we could use DAMON-based operation scheme[1]. By using it, we can ask DAMON to track access frequency of each region and make 'process_madvise(MADV_WILLNEED)[2]' call for regions having specific size and access frequency for a time interval. We also found the system is having high number of TLB misses. We tried 'always' THP enabled policy and it greatly reduced TLB misses, but the page reclamation also been more frequent due to the THP internal fragmentation caused memory bloat. We could try another DAMON-based operation scheme that applies 'MADV_HUGEPAGE' to memory regions having >=2MB size and high access frequency, while applying 'MADV_NOHUGEPAGE' to regions having <2MB size and low access frequency. We do not own the systems so we only reported the analysis results and possible optimization solutions to the customers. The customers satisfied about the analysis results and promised to try the optimization guides. [1] https://lore.kernel.org/linux-mm/20201006123931.5847-1-sjpark@amazon.com/ [2] https://lore.kernel.org/linux-api/20200622192900.22757-4-minchan@kernel.org/ Comparison with Idle Page Tracking ================================== Idle Page Tracking allows users to set and read idleness of pages using a bitmap file which represents each page with each bit of the file. One recommended usage of it is working set size detection. Users can do that by 1. find PFN of each page for workloads in interest, 2. set all the pages as idle by doing writes to the bitmap file, 3. wait until the workload accesses its working set, and 4. read the idleness of the pages again and count pages became not idle. NOTE: While Idle Page Tracking is for user space users, DAMON is primarily designed for kernel subsystems though it can easily exposed to the user space. Hence, this section only assumes such user space use of DAMON. For what use cases Idle Page Tracking would be better? ------------------------------------------------------ 1. Flexible usecases other than hotness monitoring. Because Idle Page Tracking allows users to control the primitive (Page idleness) by themselves, Idle Page Tracking users can do anything they want. Meanwhile, DAMON is primarily designed to monitor the hotness of each memory region. For this, DAMON asks users to provide sampling interval and aggregation interval. For the reason, there could be some use case that using Idle Page Tracking is simpler. 2. Physical memory monitoring. Idle Page Tracking receives PFN range as input, so natively supports physical memory monitoring. DAMON is designed to be extensible for multiple address spaces and use cases by implementing and using primitives for the given use case. Therefore, by theory, DAMON has no limitation in the type of target address space as long as primitives for the given address space exists. However, the default primitives introduced by this patchset supports only virtual address spaces. Therefore, for physical memory monitoring, you should implement your own primitives and use it, or simply use Idle Page Tracking. Nonetheless, RFC patchsets[1] for the physical memory address space primitives is already available. It also supports user memory same to Idle Page Tracking. [1] https://lore.kernel.org/linux-mm/20200831104730.28970-1-sjpark@amazon.com/ For what use cases DAMON is better? ----------------------------------- 1. Hotness Monitoring. Idle Page Tracking let users know only if a page frame is accessed or not. For hotness check, the user should write more code and use more memory. DAMON do that by itself. 2. Low Monitoring Overhead DAMON receives user's monitoring request with one step and then provide the results. So, roughly speaking, DAMON require only O(1) user/kernel context switches. In case of Idle Page Tracking, however, because the interface receives contiguous page frames, the number of user/kernel context switches increases as the monitoring target becomes complex and huge. As a result, the context switch overhead could be not negligible. Moreover, DAMON is born to handle with the monitoring overhead. Because the core mechanism is pure logical, Idle Page Tracking users might be able to implement the mechanism on thier own, but it would be time consuming and the user/kernel context switching will still more frequent than that of DAMON. Also, the kernel subsystems cannot use the logic in this case. 3. Page granularity working set size detection. Until v22 of this patchset, this was categorized as the thing Idle Page Tracking could do better, because DAMON basically maintains additional metadata for each of the monitoring target regions. So, in the page granularity working set size detection use case, DAMON would incur (number of monitoring target pages * size of metadata) memory overhead. Size of the single metadata item is about 54 bytes, so assuming 4KB pages, about 1.3% of monitoring target pages will be additionally used. All essential metadata for Idle Page Tracking are embedded in 'struct page' and page table entries. Therefore, in this use case, only one counter variable for working set size accounting is required if Idle Page Tracking is used. There are more details to consider, but roughly speaking, this is true in most cases. However, the situation changed from v23. Now DAMON supports arbitrary types of monitoring targets, which don't use the metadata. Using that, DAMON can do the working set size detection with no additional space overhead but less user-kernel context switch. A first draft for the implementation of monitoring primitives for this usage is available in a DAMON development tree[1]. An RFC patchset for it based on this patchset will also be available soon. From v24, the arbitrary type support is dropped from this patchset because this patchset doesn't introduce real use of the type. You can still get it from the DAMON development tree[2], though. [1] https://github.com/sjp38/linux/tree/damon/pgidle_hack [2] https://github.com/sjp38/linux/tree/damon/master 4. More future usecases While Idle Page Tracking has tight coupling with base primitives (PG_Idle and page table Accessed bits), DAMON is designed to be extensible for many use cases and address spaces. If you need some special address type or want to use special h/w access check primitives, you can write your own primitives for that and configure DAMON to use those. Therefore, if your use case could be changed a lot in future, using DAMON could be better. Can I use both Idle Page Tracking and DAMON? -------------------------------------------- Yes, though using them concurrently for overlapping memory regions could result in interference to each other. Nevertheless, such use case would be rare or makes no sense at all. Even in the case, the noise would bot be really significant. So, you can choose whatever you want depending on the characteristics of your use cases. More Information ================ We prepared a showcase web site[1] that you can get more information. There are - the official documentations[2], - the heatmap format dynamic access pattern of various realistic workloads for heap area[3], mmap()-ed area[4], and stack[5] area, - the dynamic working set size distribution[6] and chronological working set size changes[7], and - the latest performance test results[8]. [1] https://damonitor.github.io/_index [2] https://damonitor.github.io/doc/html/latest-damon [3] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.0.png.html [4] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html [5] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.2.png.html [6] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html [7] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html [8] https://damonitor.github.io/test/result/perf/latest/html/index.html Baseline and Complete Git Trees =============================== The patches are based on the -mm tree. More specifically, v5.12-rc7-mmots-2021-04-11-20-49 of https://github.com/hnaz/linux-mm. You can also clone the complete git tree: $ git clone git://github.com/sjp38/linux -b damon/patches/v28 The web is also available: https://github.com/sjp38/linux/releases/tag/damon/patches/v28 Development Trees ----------------- There are a couple of trees for entire DAMON patchset series and features for future release. - For latest release: https://github.com/sjp38/linux/tree/damon/master - For next release: https://github.com/sjp38/linux/tree/damon/next Long-term Support Trees ----------------------- For people who want to test DAMON but using LTS kernels, there are another couple of trees based on two latest LTS kernels respectively and containing the 'damon/master' backports. - For v5.4.y: https://github.com/sjp38/linux/tree/damon/for-v5.4.y - For v5.10.y: https://github.com/sjp38/linux/tree/damon/for-v5.10.y Amazon Linux Kernel Trees ------------------------- DAMON is also merged in two public Amazon Linux kernel trees that based on v5.4.y[1] and v5.10.y[2]. [1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon [2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon Sequence Of Patches =================== First three patches implement the core logics of DAMON. The 1st patch introduces basic sampling based hotness monitoring for arbitrary types of targets. Following two patches implement the core mechanisms for control of overhead and accuracy, namely regions based sampling (patch 2) and adaptive regions adjustment (patch 3). Now the essential parts of DAMON is complete, but it cannot work unless someone provides monitoring primitives for a specific use case. The following two patches make it just work for virtual address spaces monitoring. The 4th patch makes 'PG_idle' can be used by DAMON and the 5th patch implements the virtual memory address space specific monitoring primitives using page table Accessed bits and the 'PG_idle' page flag. Now DAMON just works for virtual address space monitoring via the kernel space api. To let the user space users can use DAMON, following four patches add interfaces for them. The 6th patch adds a tracepoint for monitoring results. The 7th patch implements a DAMON application kernel module, namely damon-dbgfs, that simply wraps DAMON and exposes DAMON interface to the user space via the debugfs interface. The 8th patch further exports pid of monitoring thread (kdamond) to user space for easier cpu usage accounting, and the 9th patch makes the debugfs interface to support multiple contexts. Three patches for maintainability follows. The 10th patch adds documentations for both the user space and the kernel space. The 11th patch provides unit tests (based on the kunit) while the 12th patch adds user space tests (based on the kselftest). Finally, the last patch (13th) updates the MAINTAINERS file. Patch History ============= Changes from v28 (https://lore.kernel.org/linux-mm/20210413142904.556-1-sj38.park@gmail.com/) - Rebase on latest -mm tree (v5.13-rc1-mmots-2021-05-13-17-23) Changes from v27 (https://lore.kernel.org/linux-mm/20210408134854.31625-1-sj38.park@gmail.com/) - Rebase on latest -mm tree (v5.12-rc7-mmots-2021-04-11-20-49) - dbgfs: Fix wrong failure handlings (Stefan Nuernberger) - dbgfs: Change return type of 'dbgfs_fill_ctx_dir()' to void (Greg KH) Changes from v26 (https://lore.kernel.org/linux-mm/20210330090537.12143-1-sj38.park@gmail.com/) - Rebase on latest -mm tree (v5.12-rc6-mmots-2021-04-06-22-33) - Check kmalloc() failures in dbgfs init (Greg KH) - Fix a typo: s/stollen/stolen/ (Stefan Nuernberger) - Update document for updated user space tool path Changes from v25 (https://lore.kernel.org/linux-mm/20210318100856.34715-1-sj38.park@gmail.com/) - Rebase on latest -mm tree (v5.12-rc4-mmots-2021-03-28-16-40) - Remove unnecessary test code that dependent on record feature - Handle special mappings having no corresponding 'struct page' (Guoju Fang) Changes from v24 (https://lore.kernel.org/linux-mm/20210204153150.15948-1-sjpark@amazon.com/) - Rebase on latest -mm tree (v5.12-rc3-mmots-2021-03-17-22-26) - Ignore 'debugfs_create_{file|dir}()' return values (Greg KH) - Remove 'recording' feature (Shakeel Butt) - Remove user space tool and recording description in the documentation Changes from v23 (https://lore.kernel.org/linux-mm/20201215115448.25633-1-sjpark@amazon.com/) - Wordsmith commit messages (Shakeel Butt) - Call missed mmu_notifier_test_young() (Shakeel Butt) - Add one 'Reviewed-by' tag for PG_Idle reuse patch (Shakeel Butt) - Rename core code to be region-neutral (Shakeel Butt) - Add missed null check of 'damon_new_region()' return value (Coverity SAST) - Put pids in dbgfs error cases (Shakeel Butt) - Move arbitrary target type support out of DAMON patchset series (Shakeel Butt) - Move user space tool patch out of DAMON patchset series - Update evaluation result with DAMOOS-tuned prcl schemes Changes from v22 (https://lore.kernel.org/linux-mm/20201020085940.13875-1-sjpark@amazon.com/) - Support arbitrary targets; now DAMON incurs only zero space overhead for page granularity idleness monitoring - Reorder patches for easier review (Shakeel Butt) - Introduce arbitrary targets with sampling first, then the overhead-accuracy control logic - Introduce data structure manipulation functions when it really used. - Call callbacks explicitly, without macro (Shakeel Butt) - Rename DAMON_PRIMITIVES to DAMON_VADDR (Shakeel Butt) - Remove 'page_idle_lock' patch (Shakeel Butt) - Drop pidfd support in debugfs (Shakeel Butt) Changes from v21 (https://lore.kernel.org/linux-doc/20201005105522.23841-1-sjpark@amazon.com/) - Fix build warnings and errors (kernel test robot) - Fix a memory leak (kmemleak) - Respect KUNIT_ALL_TESTS - Rebase on v5.9 - Update the evaluation results Changes from v20 (https://lore.kernel.org/linux-mm/20200817105137.19296-1-sjpark@amazon.com/) - s/snprintf()/scnprintf() (Marco Elver) - Support multiple contexts for user space users (Shakeel Butt) - Export pid of monitoring thread to user space (Shakeel Butt) - Let coexistable with Idle Page Tracking - Place three parts of DAMON (core, primitives, and dbgfs) in different files Please refer to the v20 patchset to get older history. SeongJae Park (13): mm: Introduce Data Access MONitor (DAMON) mm/damon/core: Implement region-based sampling mm/damon: Adaptively adjust regions mm/idle_page_tracking: Make PG_idle reusable mm/damon: Implement primitives for the virtual memory address spaces mm/damon: Add a tracepoint mm/damon: Implement a debugfs-based user space interface mm/damon/dbgfs: Export kdamond pid to the user space mm/damon/dbgfs: Support multiple contexts Documentation: Add documents for DAMON mm/damon: Add kunit tests mm/damon: Add user space selftests MAINTAINERS: Update for DAMON Documentation/admin-guide/mm/damon/guide.rst | 158 ++++ Documentation/admin-guide/mm/damon/index.rst | 15 + Documentation/admin-guide/mm/damon/plans.rst | 29 + Documentation/admin-guide/mm/damon/start.rst | 114 +++ Documentation/admin-guide/mm/damon/usage.rst | 112 +++ Documentation/admin-guide/mm/index.rst | 1 + Documentation/vm/damon/api.rst | 20 + Documentation/vm/damon/design.rst | 166 ++++ Documentation/vm/damon/eval.rst | 232 ++++++ Documentation/vm/damon/faq.rst | 58 ++ Documentation/vm/damon/index.rst | 31 + Documentation/vm/index.rst | 1 + MAINTAINERS | 12 + include/linux/damon.h | 265 +++++++ include/linux/page-flags.h | 4 +- include/linux/page_ext.h | 2 +- include/linux/page_idle.h | 6 +- include/trace/events/damon.h | 43 ++ include/trace/events/mmflags.h | 2 +- mm/Kconfig | 10 + mm/Makefile | 1 + mm/damon/Kconfig | 69 ++ mm/damon/Makefile | 5 + mm/damon/core-test.h | 253 ++++++ mm/damon/core.c | 718 ++++++++++++++++++ mm/damon/dbgfs-test.h | 126 +++ mm/damon/dbgfs.c | 615 +++++++++++++++ mm/damon/vaddr-test.h | 328 ++++++++ mm/damon/vaddr.c | 623 +++++++++++++++ mm/page_ext.c | 12 +- mm/page_idle.c | 10 - tools/testing/selftests/damon/Makefile | 7 + .../selftests/damon/_chk_dependency.sh | 28 + .../testing/selftests/damon/debugfs_attrs.sh | 98 +++ 34 files changed, 4156 insertions(+), 18 deletions(-) create mode 100644 Documentation/admin-guide/mm/damon/guide.rst create mode 100644 Documentation/admin-guide/mm/damon/index.rst create mode 100644 Documentation/admin-guide/mm/damon/plans.rst create mode 100644 Documentation/admin-guide/mm/damon/start.rst create mode 100644 Documentation/admin-guide/mm/damon/usage.rst create mode 100644 Documentation/vm/damon/api.rst create mode 100644 Documentation/vm/damon/design.rst create mode 100644 Documentation/vm/damon/eval.rst create mode 100644 Documentation/vm/damon/faq.rst create mode 100644 Documentation/vm/damon/index.rst create mode 100644 include/linux/damon.h create mode 100644 include/trace/events/damon.h create mode 100644 mm/damon/Kconfig create mode 100644 mm/damon/Makefile create mode 100644 mm/damon/core-test.h create mode 100644 mm/damon/core.c create mode 100644 mm/damon/dbgfs-test.h create mode 100644 mm/damon/dbgfs.c create mode 100644 mm/damon/vaddr-test.h create mode 100644 mm/damon/vaddr.c create mode 100644 tools/testing/selftests/damon/Makefile create mode 100644 tools/testing/selftests/damon/_chk_dependency.sh create mode 100755 tools/testing/selftests/damon/debugfs_attrs.sh