kernel/linux.git/mm/damon/core.c, branch v6.4

mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()

2023-06-12T18:31:52+00:00

If 'aggr_interval' is smaller than 'sample_interval', max_nr_accesses in damon_nr_accesses_to_accesses_bp() becomes zero which leads to divide error, let's validate the values of them in damon_set_attrs() to fix it, which similar to others attrs check. Link: https://lkml.kernel.org/r/20230527032101.167788-1-wangkefeng.wang@huawei.com Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes") Reported-by: syzbot+841a46899768ec7bec67@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=841a46899768ec7bec67 Link: https://lore.kernel.org/damon/00000000000055fc4e05fc975bc2@google.com/ Reviewed-by: SeongJae Park Signed-off-by: Kefeng Wang Cc: Signed-off-by: Andrew Morton

mm/damon/core: update monitoring results for new monitoring attributes

2023-02-03T06:33:26+00:00

region->nr_accesses is the number of sampling intervals in the last aggregation interval that access to the region has found, and region->age is the number of aggregation intervals that its access pattern has maintained. Hence, the real meaning of the two fields' values is depending on current sampling and aggregation intervals. This means the values need to be updated for every sampling and/or aggregation intervals updates. As DAMON core doesn't, it is a duty of in-kernel DAMON framework applications like DAMON sysfs interface, or the userspace users. Handling it in userspace or in-kernel DAMON application is complicated, inefficient, and repetitive compared to doing the update in DAMON core. Do the update in DAMON core. Link: https://lkml.kernel.org/r/20230119013831.1911-3-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton

mm/damon/core: skip apply schemes if empty

2023-02-03T06:33:22+00:00

Sometimes there is no scheme in damon's context, for example just use damo record to monitor workload's data access pattern. If current damon context doesn't have any scheme in the list, kdamond has no need to iterate over list of all targets and regions but do nothing. So, skip apply schemes when ctx->schemes is empty. Link: https://lkml.kernel.org/r/20230116062347.1148553-1-huaisheng.ye@intel.com Signed-off-by: Huaisheng Ye Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: implement damos filter

2023-01-19T01:12:43+00:00

Patch series "implement DAMOS filtering for anon pages and/or specific memory cgroups" DAMOS let users do system operations in a data access pattern oriented way. The data access pattern, which is extracted by DAMON, is somewhat accurate more than what user space could know in many cases. However, in some situation, users could know something more than the kernel about the pattern or some special requirements for some types of memory or processes. For example, some users would have slow swap devices and knows latency-ciritical processes and therefore want to use DAMON-based proactive reclamation (DAMON_RECLAIM) for only non-anonymous pages of non-latency-critical processes. For such restriction, users could exclude the memory regions from the initial monitoring regions and use non-dynamic monitoring regions update monitoring operations set including fvaddr and paddr. They could also adjust the DAMOS target access pattern. For dynamically changing memory layout and access pattern, those would be not enough. To help the case, add an interface, namely DAMOS filters, which can be used to avoid the DAMOS actions be applied to specific types of memory, to DAMON kernel API (damon.h). At the moment, it supports filtering anonymous pages and/or specific memory cgroups in or out for each DAMOS scheme. This patchset adds the support for all DAMOS actions that 'paddr' monitoring operations set supports ('pageout', 'lru_prio', and 'lru_deprio'), and the functionality is exposed via DAMON kernel API (damon.h) the DAMON sysfs interface (/sys/kernel/mm/damon/admins/), and DAMON_RECLAIM module parameters. Patches Sequence ---------------- First patch implements DAMOS filter interface to DAMON kernel API. Second patch makes the physical address space monitoring operations set to support the filters from all supporting DAMOS actions. Third patch adds anonymous pages filter support to DAMON_RECLAIM, and the fourth patch documents the DAMON_RECLAIM's new feature. Fifth to seventh patches implement DAMON sysfs files for support of the filters, and eighth patch connects the file to use DAMOS filters feature. Ninth patch adds simple self test cases for DAMOS filters of the sysfs interface. Finally, following two patches (tenth and eleventh) document the new features and interfaces. This patch (of 11): DAMOS lets users do system operation in a data access pattern oriented way. The data access pattern, which is extracted by DAMON, is somewhat accurate more than what user space could know in many cases. However, in some situation, users could know something more than the kernel about the pattern or some special requirements for some types of memory or processes. For example, some users would have slow swap devices and knows latency-ciritical processes and therefore want to use DAMON-based proactive reclamation (DAMON_RECLAIM) for only non-anonymous pages of non-latency-critical processes. For such restriction, users could exclude the memory regions from the initial monitoring regions and use non-dynamic monitoring regions update monitoring operations set including fvaddr and paddr. They could also adjust the DAMOS target access pattern. For dynamically changing memory layout and access pattern, those would be not enough. To help the case, add an interface, namely DAMOS filters, which can be used to avoid the DAMOS actions be applied to specific types of memory, to DAMON kernel API (damon.h). At the moment, it supports filtering anonymous pages and/or specific memory cgroups in or out for each DAMOS scheme. Note that this commit adds only the interface to the DAMON kernel API. The impelmentation should be made in the monitoring operations sets, and following commits will add that. Link: https://lkml.kernel.org/r/20221205230830.144349-1-sj@kernel.org Link: https://lkml.kernel.org/r/20221205230830.144349-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Shuah Khan Signed-off-by: Andrew Morton

mm/damon/core: add a callback for scheme target regions check

2022-11-30T23:58:43+00:00

Patch series "efficiently expose damos action tried regions information". DAMON users can retrieve the monitoring results via 'after_aggregation' callbacks if the user is using the kernel API, or 'damon_aggregated' tracepoint if the user is in the user space. Those are useful if full monitoring results are necessary. However, if the user has interest in only a snapshot of the results for some regions having specific access pattern, the interfaces could be inefficient. For example, some users only want to know which memory regions are not accessed for more than a specific time at the moment. Also, some DAMOS users would want to know exactly to what memory regions the schemes' actions tried to be applied, for a debugging or a tuning. As DAMOS has its internal mechanism for quota and regions prioritization, the users would need to simulate DAMOS' mechanism against the monitoring results. That's unnecessarily complex. This patchset implements DAMON kernel API callbacks and sysfs directory for efficient exposure of the information for the use cases. The new callback will be called for each region when a DAMOS action is gonna tried to be applied to it. The sysfs directory will be called 'tried_regions' and placed under each scheme sysfs directory. Users can write a special keyworkd, 'update_schemes_regions', to the 'state' file of a kdamond sysfs directory. Then, DAMON sysfs interface will fill the directory with the information of regions that corresponding scheme action was tried to be applied for next one aggregation interval. Patches Sequence ---------------- The first one (patch 1) implements the callback for the kernel space users. Following two patches (patches 2 and 3) implements sysfs directories for the information and its sub directories. Two patches (patches 4 and 5) for implementing the special keywords for filling the data to and cleaning up the directories follow. Patch 6 adds a selftest for the new sysfs directory. Finally, two patches (patches 7 and 8) document the new feature in the administrator guide and the ABI document. This patch (of 8): Getting DAMON monitoring results of only specific access pattern (e.g., getting address ranges of memory that not accessed at all for two minutes) can be useful for efficient monitoring of the system. The information can also be helpful for deep level investigation of DAMON-based operation schemes. For that, users need to record (in case of the user space users) or iterate (in case of the kernel space users) full monitoring results and filter it out for the specific access pattern. In case of the DAMOS investigation, users will even need to simulate DAMOS' quota and prioritization mechanisms. It's inefficient and complex. Add a new DAMON callback that will be called before each scheme is applied to each region. DAMON kernel API users will be able to do the query-like monitoring results collection, or DAMOS investigation in an efficient and simple way using it. Commits for providing the capability to the user space users will follow. Link: https://lkml.kernel.org/r/20221101220328.95765-1-sj@kernel.org Link: https://lkml.kernel.org/r/20221101220328.95765-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Shuah Khan Signed-off-by: Andrew Morton

mm/damon/core: split out scheme quota adjustment logic into a new function

2022-11-30T23:01:25+00:00

DAMOS quota adjustment logic in 'kdamond_apply_schemes()', has some amount of code, and the logic is not so straightforward. Split it out to a new function for better readability. Link: https://lkml.kernel.org/r/20221026225943.100429-5-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: split out scheme stat update logic into a new function

2022-11-30T23:01:24+00:00

The function for applying a given DAMON scheme action to a given DAMON region, 'damos_apply_scheme()' is not quite short. Make it better to read by splitting out the stat update logic into a new function. Link: https://lkml.kernel.org/r/20221026225943.100429-4-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: split damos application logic into a new function

2022-11-30T23:01:24+00:00

The DAMOS action applying function, 'damon_do_apply_schemes()', is still long and not easy to read. Split out the code for applying a single action to a single region into a new function for better readability. Link: https://lkml.kernel.org/r/20221026225943.100429-3-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: split out DAMOS-charged region skip logic into a new function

2022-11-30T23:01:24+00:00

Patch series "mm/damon: cleanup and refactoring code", v2. This patchset cleans up and refactors a range of DAMON code including the core, DAMON sysfs interface, and DAMON modules, for better readability and convenient future feature implementations. In detail, this patchset splits unnecessarily long and complex functions in core into smaller functions (patches 1-4). Then, it cleans up the DAMON sysfs interface by using more type-safe code (patch 5) and removing unnecessary function parameters (patch 6). Further, it refactor the code by distributing the code into multiple files (patches 7-10). Last two patches (patches 11 and 12) deduplicates and remove unnecessary header inclusion in DAMON modules (reclaim and lru_sort). This patch (of 12): The DAMOS action applying function, 'damon_do_apply_schemes()', is quite long and not so simple. Split out the already quota-charged region skip code, which is not a small amount of simple code, into a new function with some comments for better readability. Link: https://lkml.kernel.org/r/20221026225943.100429-1-sj@kernel.org Link: https://lkml.kernel.org/r/20221026225943.100429-2-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-14T19:28:43+00:00

Pull more MM updates from Andrew Morton: - fix a race which causes page refcounting errors in ZONE_DEVICE pages (Alistair Popple) - fix userfaultfd test harness instability (Peter Xu) - various other patches in MM, mainly fixes * tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (29 commits) highmem: fix kmap_to_page() for kmap_local_page() addresses mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page mm/selftest: uffd: explain the write missing fault check mm/hugetlb: use hugetlb_pte_stable in migration race check mm/hugetlb: fix race condition of uffd missing/minor handling zram: always expose rw_page LoongArch: update local TLB if PTE entry exists mm: use update_mmu_tlb() on the second thread kasan: fix array-bounds warnings in tests hmm-tests: add test for migrate_device_range() nouveau/dmem: evict device private memory during release nouveau/dmem: refactor nouveau_dmem_fault_copy_one() mm/migrate_device.c: add migrate_device_range() mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page() mm/memremap.c: take a pgmap reference on page allocation mm: free device private pages have zero refcount mm/memory.c: fix race when faulting a device private page mm/damon: use damon_sz_region() in appropriate place mm/damon: move sz_damon_region to damon_sz_region lib/test_meminit: add checks for the allocation functions ...