- 12 Sep, 2022 40 commits
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David Heidelberg authored
zswap has been with us since 2013, and it's widely used in many products. Link: https://lkml.kernel.org/r/20220823152033.66682-1-david@ixit.czSigned-off-by:
David Heidelberg <david@ixit.cz> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Barry Song <song.bao.hua@hisilicon.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Sergey Senozhatsky authored
We do all reset operations under write lock, so we don't need to save ->disksize and ->comp to stack variables. Another thing is that ->comp is freed during zram reset, but comp pointer is not NULL-ed, so zram keeps the freed pointer value. Link: https://lkml.kernel.org/r/20220824035100.971816-1-senozhatsky@chromium.orgSigned-off-by:
Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by:
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Alistair Popple authored
When pinning pages with FOLL_LONGTERM check_and_migrate_movable_pages() is called to migrate pages out of zones which should not contain any longterm pinned pages. When migration succeeds all pages will have been unpinned so pinning needs to be retried. Migration can also fail, in which case the pages will also have been unpinned but the operation should not be retried. If all pages are in the correct zone nothing will be unpinned and no retry is required. The logic in check_and_migrate_movable_pages() tracks unnecessary state and the return codes for each case are difficult to follow. Refactor the code to clean this up. No behaviour change is intended. [akpm@linux-foundation.org: fix unused var warning] Link: https://lkml.kernel.org/r/19583d1df07fdcb99cfa05c265588a3fa58d1902.1661317396.git-series.apopple@nvidia.comSigned-off-by:
Alistair Popple <apopple@nvidia.com> Reviewed-by:
John Hubbard <jhubbard@nvidia.com> Cc: Alex Sierra <alex.sierra@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Felix Kuehling <felix.kuehling@amd.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Shigeru Yoshida <syoshida@redhat.com> Signed-off-by:
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Alistair Popple authored
gup_flags is passed to check_and_migrate_movable_pages() so that it can call either put_page() or unpin_user_page() to drop the page reference. However check_and_migrate_movable_pages() is only called for FOLL_LONGTERM, which implies FOLL_PIN so there is no need to pass gup_flags. Link: https://lkml.kernel.org/r/d611c65a9008ff55887307df457c6c2220ad6163.1661317396.git-series.apopple@nvidia.comSigned-off-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
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Bui Quang Minh authored
In page_counter_set_max, we want to make sure the new limit is not below the concurrently-changing counter value. We read the counter and check that the limit is not below the counter before the swap. After the swap, we read the counter again and retry in case the counter is incremented as this may violate the requirement. Even though the page_counter_try_charge can see the old limit, it is guaranteed that the counter is not above the old limit after the increment. So in case the new limit is not below the old limit, the counter is guaranteed to be not above the new limit too. We can skip the retry in this case to optimize a little bit. Link: https://lkml.kernel.org/r/20220821154055.109635-1-minhquangbui99@gmail.comSigned-off-by:
Bui Quang Minh <minhquangbui99@gmail.com> Signed-off-by:
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Rolf Eike Beer authored
Link: https://lkml.kernel.org/r/8991525.CDJkKcVGEf@devpool047Signed-off-by:
Rolf Eike Beer <eb@emlix.com> Signed-off-by:
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Rolf Eike Beer authored
Empty PTEs are passed to the pte_entry callback, not to pte_hole. Link: https://lkml.kernel.org/r/3695521.kQq0lBPeGt@devpool047Signed-off-by:
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Yang Shi authored
Workingset refault stats are important and useful metrics to measure how well reclaimer and swapping work and how healthy the services are, but they are just available for cgroup v2. There are still plenty users with cgroup v1, export the stats for cgroup v1. Link: https://lkml.kernel.org/r/20220816185801.651091-1-shy828301@gmail.comSigned-off-by:
Yang Shi <shy828301@gmail.com> Acked-by:
Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by:
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Kassey Li authored
It is too slow to dump all the pages, in some usage we just want to dump a given start pfn, for example: a CMA range or a single page. To speed up and save time, this change allows specifying of a start pfn by adding llseek for page_owner. Link: https://lkml.kernel.org/r/20220818022425.31056-1-quic_yingangl@quicinc.comSigned-off-by:
Kassey Li <quic_yingangl@quicinc.com> Suggested-by:
Vlastimil Babka <vbabka@suse.cz> Acked-by:
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Baolin Wang authored
pmd_huge() is usually used to indicate a pmd level hugetlb. However a pmd mapped huge page can only be THP in damon_mkold_pmd_entry() or damon_young_pmd_entry(), so replace pmd_huge() with pmd_trans_huge() in this case to make the code more readable according to the discussion [1]. [1] https://lore.kernel.org/all/098c1480-416d-bca9-cedb-ca495df69b64@linux.alibaba.com/ Link: https://lkml.kernel.org/r/a9e010ca5d299e18d740c7c52290ecb6a014dde6.1660805030.git.baolin.wang@linux.alibaba.comSigned-off-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by:
Muchun Song <songmuchun@bytedance.com> Reviewed-by:
SeongJae Park <sj@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
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Baolin Wang authored
pmd_huge() is used to validate if the pmd entry is mapped by a huge page, also including the case of non-present (migration or hwpoisoned) pmd entry on arm64 or x86 architectures. This means that pmd_pfn() can not get the correct pfn number for a non-present pmd entry, which will cause damon_get_page() to get an incorrect page struct (also may be NULL by pfn_to_online_page()), making the access statistics incorrect. This means that the DAMON may make incorrect decision according to the incorrect statistics, for example, DAMON may can not reclaim cold page in time due to this cold page was regarded as accessed mistakenly if DAMOS_PAGEOUT operation is specified. Moreover it does not make sense that we still waste time to get the page of the non-present entry. Just treat it as not-accessed and skip it, which maintains consistency with non-present pte level entries. So add pmd entry present validation to fix the above issues. Link: https://lkml.kernel.org/r/58b1d1f5fbda7db49ca886d9ef6783e3dcbbbc98.1660805030.git.baolin.wang@linux.alibaba.com Fixes: 3f49584b ("mm/damon: implement primitives for the virtual memory address spaces") Signed-off-by:
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Yin Fengwei authored
If there is private data attached to a THP, the refcount of THP will be increased and will prevent the THP from being split. Attempt to release any private data attached to the THP before attempting the split to increase the chance of splitting successfully. There was a memory failure issue hit during HW error injection testing with 5.18 kernel + xfs as rootfs. The test was killed and a system reboot was required to re-run the test. The issue was tracked down to a THP split failure caused by the memory failure not being handled. The page dump showed: [ 1785.433075] page:0000000025f9530b refcount:18 mapcount:0 mapping:000000008162eea7 index:0xa10 pfn:0x2f0200 [ 1785.443954] head:0000000025f9530b order:4 compound_mapcount:0 compound_pincount:0 [ 1785.452408] memcg:ff4247f2d28e9000 [ 1785.456304] aops:xfs_address_space_operations ino:8555182 dentry name:"baseos-filenames.solvx" [ 1785.466612] flags: 0x1000000000012036(referenced|uptodate|lru|active|private|head|node=0|zone=2) [ 1785.476514] raw: 1000000000012036 ffb9460f8bc07c08 ffb9460f8bc08408 ff4247f22e6299f8 [ 1785.485268] raw: 0000000000000a10 ff4247f194ade900 00000012ffffffff ff4247f2d28e9000 It was like the error was injected to a large folio for xfs with private data attached. With private data released before splitting the THP, the test case could be run successfully many times without rebooting the system. Link: https://lkml.kernel.org/r/20220810064907.582899-1-fengwei.yin@intel.comCo-developed-by:
Qiuxu Zhuo <qiuxu.zhuo@intel.com> Signed-off-by:
Yin Fengwei <fengwei.yin@intel.com> Suggested-by:
Matthew Wilcox <willy@infradead.org> Reviewed-by:
Miaohe Lin <linmiaohe@huawei.com> Reviewed-by:
Aaron Lu <aaron.lu@intel.com> Signed-off-by:
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Qi Zheng authored
When the pgtable is NULL in the set_huge_zero_page(), we should not increment the count of PTE page table pages by calling mm_inc_nr_ptes(). Otherwise we may receive the following warning when the mm exits: BUG: non-zero pgtables_bytes on freeing mm Now we can't observe the above warning since only do_huge_pmd_anonymous_page() invokes set_huge_zero_page() and the pgtable can not be NULL. Therefore, instead of moving mm_inc_nr_ptes() to the non-NULL branch of pgtable, it is better to remove the redundant pgtable check directly. Link: https://lkml.kernel.org/r/20220818082748.40021-1-zhengqi.arch@bytedance.comSigned-off-by:
Qi Zheng <zhengqi.arch@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
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Kefeng Wang authored
Squash the __soft_offline_page() into soft_offline_in_use_page() and kill __soft_offline_page(). [wangkefeng.wang@huawei.com: update hpage when try_to_split_thp_page() succeeds] Link: https://lkml.kernel.org/r/20220830104654.28234-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20220819033402.156519-2-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by:
Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
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Kefeng Wang authored
Open-code the page_handle_poison() into soft_offline_page() and kill unneeded soft_offline_free_page(). Link: https://lkml.kernel.org/r/20220819033402.156519-1-wangkefeng.wang@huawei.comSigned-off-by:
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Muchun Song authored
We can choose to copy three contiguous tail pages' content to the first three pages instead of copying one by one to simplify the code and reduce code size from 229 bytes to 63 bytes. The BUILD_BUG_ON() aims to avoid out-of-bounds accesses. Link: https://lkml.kernel.org/r/20220819035532.6189-1-songmuchun@bytedance.comSigned-off-by:
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Miaohe Lin authored
For reserved pages, HWPoison flag will be set without increasing the page refcnt. So we shouldn't even try to unpoison these pages and thus decrease the page refcnt unexpectly. Add a PageReserved() check to filter this case out and remove the below unneeded zero page (zero page is reserved) check. Link: https://lkml.kernel.org/r/20220818130016.45313-7-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
If try_to_unmap() fails, the hwpoisoned page still resides in the address space of some processes. We should kill these processes or the hwpoisoned page might be consumed later. collect_procs() is always called to collect relevant processes now so they can be killed later if unmap fails. [linmiaohe@huawei.com: v2] Link: https://lkml.kernel.org/r/20220823032346.4260-6-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220818130016.45313-6-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
After kill_procs(), tk will be freed without being removed from the to_kill list. In the next iteration, the freed list entry in the to_kill list will be accessed, thus leading to use-after-free issue. Adding list_del() in kill_procs() to fix the issue. Link: https://lkml.kernel.org/r/20220823032346.4260-5-linmiaohe@huawei.com Fixes: c36e2024 ("mm: introduce mf_dax_kill_procs() for fsdax case") Signed-off-by:
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Miaohe Lin authored
When hwpoison_filter() refuses to soft offline a page, the page refcnt incremented previously by MF_COUNT_INCREASED would have been consumed via get_hwpoison_page() if ret <= 0. So the put_ref_page() here will put the extra one. Remove it to fix the issue. Link: https://lkml.kernel.org/r/20220818130016.45313-4-linmiaohe@huawei.com Fixes: 9113eaf3 ("mm/memory-failure.c: add hwpoison_filter for soft offline") Signed-off-by:
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Miaohe Lin authored
When free_raw_hwp_pages() fails its work, the refcnt of the hugetlb page would have been incremented if ret > 0. Using put_page() to fix refcnt leaking in this case. Link: https://lkml.kernel.org/r/20220818130016.45313-3-linmiaohe@huawei.com Fixes: debb6b9c3fdd ("mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage") Signed-off-by:
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Miaohe Lin authored
Patch series "A few fixup patches for memory-failure", v2. This series contains a few fixup patches to fix incorrect update of page refcnt, fix possible use-after-free issue and so on. More details can be found in the respective changelogs. This patch (of 6): When hwpoison_filter() refuses to hwpoison a hugetlb page, the refcnt of the page would have been incremented if res == 1. Using put_page() to fix the refcnt leaking in this case. Link: https://lkml.kernel.org/r/20220823032346.4260-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220818130016.45313-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220818130016.45313-2-linmiaohe@huawei.com Fixes: 405ce051 ("mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()") Signed-off-by:
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Charan Teja Kalla authored
The below is one path where race between page_ext and offline of the respective memory blocks will cause use-after-free on the access of page_ext structure. process1 process2 --------- --------- a)doing /proc/page_owner doing memory offline through offline_pages. b) PageBuddy check is failed thus proceed to get the page_owner information through page_ext access. page_ext = lookup_page_ext(page); migrate_pages(); ................. Since all pages are successfully migrated as part of the offline operation,send MEM_OFFLINE notification where for page_ext it calls: offline_page_ext()--> __free_page_ext()--> free_page_ext()--> vfree(ms->page_ext) mem_section->page_ext = NULL c) Check for the PAGE_EXT flags in the page_ext->flags access results into the use-after-free (leading to the translation faults). As mentioned above, there is really no synchronization between page_ext access and its freeing in the memory_offline. The memory offline steps(roughly) on a memory block is as below: 1) Isolate all the pages 2) while(1) try free the pages to buddy.(->free_list[MIGRATE_ISOLATE]) 3) delete the pages from this buddy list. 4) Then free page_ext.(Note: The struct page is still alive as it is freed only during hot remove of the memory which frees the memmap, which steps the user might not perform). This design leads to the state where struct page is alive but the struct page_ext is freed, where the later is ideally part of the former which just representing the page_flags (check [3] for why this design is chosen). The abovementioned race is just one example __but the problem persists in the other paths too involving page_ext->flags access(eg: page_is_idle())__. Fix all the paths where offline races with page_ext access by maintaining synchronization with rcu lock and is achieved in 3 steps: 1) Invalidate all the page_ext's of the sections of a memory block by storing a flag in the LSB of mem_section->page_ext. 2) Wait until all the existing readers to finish working with the ->page_ext's with synchronize_rcu(). Any parallel process that starts after this call will not get page_ext, through lookup_page_ext(), for the block parallel offline operation is being performed. 3) Now safely free all sections ->page_ext's of the block on which offline operation is being performed. Note: If synchronize_rcu() takes time then optimizations can be done in this path through call_rcu()[2]. Thanks to David Hildenbrand for his views/suggestions on the initial discussion[1] and Pavan kondeti for various inputs on this patch. [1] https://lore.kernel.org/linux-mm/59edde13-4167-8550-86f0-11fc67882107@quicinc.com/ [2] https://lore.kernel.org/all/a26ce299-aed1-b8ad-711e-a49e82bdd180@quicinc.com/T/#u [3] https://lore.kernel.org/all/6fa6b7aa-731e-891c-3efb-a03d6a700efa@redhat.com/ [quic_charante@quicinc.com: rename label `loop' to `ext_put_continue' per David] Link: https://lkml.kernel.org/r/1661496993-11473-1-git-send-email-quic_charante@quicinc.com Link: https://lkml.kernel.org/r/1660830600-9068-1-git-send-email-quic_charante@quicinc.comSigned-off-by:
Charan Teja Kalla <quic_charante@quicinc.com> Suggested-by:
Michal Hocko <mhocko@suse.com> Acked-by:
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Matthew Wilcox authored
If the pages being mapped are in HIGHMEM, page_address() returns NULL. This probably wasn't noticed before because there aren't currently any architectures with HAVE_ARCH_HUGE_VMALLOC and HIGHMEM, but it's simpler to call page_to_phys() and futureproofs us against such configurations existing. Link: https://lkml.kernel.org/r/Yv6qHc6e+m7TMWhi@casper.infradead.org Fixes: 121e6f32 ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by:
William Kucharski <william.kucharski@oracle.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Cc: Uladzislau Rezki <urezki@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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xupanda authored
Fix a spelling mistake in comment. Link: https://lkml.kernel.org/r/20220815065102.74347-1-xu.panda@zte.com.cnReported-by:
Zeal Robot <zealci@zte.com.cn> Signed-off-by:
xupanda <xu.panda@zte.com.cn> Signed-off-by:
CGEL ZTE <cgel.zte@gmail.com> Reviewed-by:
Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by:
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Kefeng Wang authored
find_min_pfn_with_active_regions() is only called from free_area_init(). Open-code the PHYS_PFN(memblock_start_of_DRAM()) into free_area_init(), and kill find_min_pfn_with_active_regions(). Link: https://lkml.kernel.org/r/20220815111017.39341-1-wangkefeng.wang@huawei.comSigned-off-by:
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Zi Yan authored
This Kconfig option is used by individual arch to set its desired MAX_ORDER. Rename it to reflect its actual use. Link: https://lkml.kernel.org/r/20220815143959.1511278-1-zi.yan@sent.comAcked-by:
Mike Rapoport <rppt@linux.ibm.com> Signed-off-by:
Zi Yan <ziy@nvidia.com> Acked-by: Guo Ren <guoren@kernel.org> [csky] Acked-by:
Arnd Bergmann <arnd@arndb.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Acked-by: Huacai Chen <chenhuacai@kernel.org> [LoongArch] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Taichi Sugaya <sugaya.taichi@socionext.com> Cc: Neil Armstrong <narmstrong@baylibre.com> Cc: Qin Jian <qinjian@cqplus1.com> Cc: Guo Ren <guoren@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Signed-off-by:
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Alexey Romanov authored
Emails are not documentation. [akpm@linux-foundation.org: fix whitespace damage, repair doc reference] [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/20220815144825.39001-1-avromanov@sberdevices.ruSigned-off-by:
Alexey Romanov <avromanov@sberdevices.ru> Reviewed-by:
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Miaohe Lin authored
If the pagetables are shared, we shouldn't copy or take references. Since src could have unshared and dst shares with another vma, huge_pte_none() is thus used to determine whether dst_pte is shared. But this check isn't reliable. A shared pte could have pte none in pagetable in fact. The page count of ptep page should be checked here in order to reliably determine whether pte is shared. [lukas.bulwahn@gmail.com: remove unused local variable dst_entry in copy_hugetlb_page_range()] Link: https://lkml.kernel.org/r/20220822082525.26071-1-lukas.bulwahn@gmail.com Link: https://lkml.kernel.org/r/20220816130553.31406-7-linmiaohe@huawei.comSigned-off-by:
Lukas Bulwahn <lukas.bulwahn@gmail.com> Reviewed-by:
Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by:
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Miaohe Lin authored
The sysfs group per_node_hstate_attr_group and hstate_demote_attr_group when h->demote_order != 0 are created in hugetlb_register_node(). But these sysfs groups are not removed when unregister the node, thus sysfs group is leaked. Using sysfs_remove_group() to fix this issue. Link: https://lkml.kernel.org/r/20220816130553.31406-6-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
The memory barrier smp_wmb() is needed to make sure that preceding stores to the page contents become visible before the below set_pte_at() write. Link: https://lkml.kernel.org/r/20220816130553.31406-5-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
When huge_add_to_page_cache() fails, the page is freed directly without calling restore_reserve_on_error() to restore reserve for newly allocated pages not in page cache. Fix this by calling restore_reserve_on_error() when huge_add_to_page_cache fails. [linmiaohe@huawei.com: remove err == -EEXIST check and retry logic] Link: https://lkml.kernel.org/r/20220823030209.57434-4-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220816130553.31406-4-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
If sysfs_create_group() fails with hstate_attr_group, hstate_kobjs[hi] will be set to NULL. Then it will be passed to sysfs_create_group() if h->demote_order != 0 thus triggering WARN_ON(!kobj) check. Fix this by making sure hstate_kobjs[hi] != NULL when calling sysfs_create_group. Link: https://lkml.kernel.org/r/20220816130553.31406-3-linmiaohe@huawei.com Fixes: 79dfc695 ("hugetlb: add demote hugetlb page sysfs interfaces") Signed-off-by:
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Miaohe Lin authored
Patch series "A few fixup patches for hugetlb". This series contains a few fixup patches to fix incorrect update of max_huge_pages, fix WARN_ON(!kobj) in sysfs_create_group() and so on. More details can be found in the respective changelogs. This patch (of 6): There should be pages_per_huge_page(h) / pages_per_huge_page(target_hstate) pages incremented for target_hstate->max_huge_pages when page is demoted. Update max_huge_pages accordingly for consistency. Link: https://lkml.kernel.org/r/20220816130553.31406-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220816130553.31406-2-linmiaohe@huawei.comSigned-off-by:
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Huang Ying authored
The promotion hot threshold is workload and system configuration dependent. So in this patch, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. If the hint page fault latency of a page is less than the hot threshold, we will try to promote the page, and the page is called the candidate promotion page. If the number of the candidate promotion pages in the statistics interval is much more than the promotion rate limit, the hot threshold will be decreased to reduce the number of the candidate promotion pages. Otherwise, the hot threshold will be increased to increase the number of the candidate promotion pages. To make the above method works, in each statistics interval, the total number of the pages to check (on which the hint page faults occur) and the hot/cold distribution need to be stable. Because the page tables are scanned linearly in NUMA balancing, but the hot/cold distribution isn't uniform along the address usually, the statistics interval should be larger than the NUMA balancing scan period. So in the patch, the max scan period is used as statistics interval and it works well in our tests. Link: https://lkml.kernel.org/r/20220713083954.34196-4-ying.huang@intel.comSigned-off-by:
"Huang, Ying" <ying.huang@intel.com> Reviewed-by:
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Huang Ying authored
In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patch as the page promotion rate limit mechanism. The number of the candidate pages to be promoted to the fast memory node via NUMA balancing is counted, if the count exceeds the limit specified by the users, the NUMA balancing promotion will be stopped until the next second. A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added for the users to specify the limit. Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.comSigned-off-by:
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Huang Ying authored
Patch series "memory tiering: hot page selection", v4. To optimize page placement in a memory tiering system with NUMA balancing, the hot pages in the slow memory nodes need to be identified. Essentially, the original NUMA balancing implementation selects the mostly recently accessed (MRU) pages to promote. But this isn't a perfect algorithm to identify the hot pages. Because the pages with quite low access frequency may be accessed eventually given the NUMA balancing page table scanning period could be quite long (e.g. 60 seconds). So in this patchset, we implement a new hot page identification algorithm based on the latency between NUMA balancing page table scanning and hint page fault. Which is a kind of mostly frequently accessed (MFU) algorithm. In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patchset as the page promotion rate limit mechanism. The promotion hot threshold is workload and system configuration dependent. So in this patchset, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. We used the pmbench memory accessing benchmark tested the patchset on a 2-socket server system with DRAM and PMEM installed. The test results are as follows, pmbench score promote rate (accesses/s) MB/s ------------- ------------ base 146887704.1 725.6 hot selection 165695601.2 544.0 rate limit 162814569.8 165.2 auto adjustment 170495294.0 136.9 From the results above, With hot page selection patch [1/3], the pmbench score increases about 12.8%, and promote rate (overhead) decreases about 25.0%, compared with base kernel. With rate limit patch [2/3], pmbench score decreases about 1.7%, and promote rate decreases about 69.6%, compared with hot page selection patch. With threshold auto adjustment patch [3/3], pmbench score increases about 4.7%, and promote rate decrease about 17.1%, compared with rate limit patch. Baolin helped to test the patchset with MySQL on a machine which contains 1 DRAM node (30G) and 1 PMEM node (126G). sysbench /usr/share/sysbench/oltp_read_write.lua \ ...... --tables=200 \ --table-size=1000000 \ --report-interval=10 \ --threads=16 \ --time=120 The tps can be improved about 5%. This patch (of 3): To optimize page placement in a memory tiering system with NUMA balancing, the hot pages in the slow memory node need to be identified. Essentially, the original NUMA balancing implementation selects the mostly recently accessed (MRU) pages to promote. But this isn't a perfect algorithm to identify the hot pages. Because the pages with quite low access frequency may be accessed eventually given the NUMA balancing page table scanning period could be quite long (e.g. 60 seconds). The most frequently accessed (MFU) algorithm is better. So, in this patch we implemented a better hot page selection algorithm. Which is based on NUMA balancing page table scanning and hint page fault as follows, - When the page tables of the processes are scanned to change PTE/PMD to be PROT_NONE, the current time is recorded in struct page as scan time. - When the page is accessed, hint page fault will occur. The scan time is gotten from the struct page. And The hint page fault latency is defined as hint page fault time - scan time The shorter the hint page fault latency of a page is, the higher the probability of their access frequency to be higher. So the hint page fault latency is a better estimation of the page hot/cold. It's hard to find some extra space in struct page to hold the scan time. Fortunately, we can reuse some bits used by the original NUMA balancing. NUMA balancing uses some bits in struct page to store the page accessing CPU and PID (referring to page_cpupid_xchg_last()). Which is used by the multi-stage node selection algorithm to avoid to migrate pages shared accessed by the NUMA nodes back and forth. But for pages in the slow memory node, even if they are shared accessed by multiple NUMA nodes, as long as the pages are hot, they need to be promoted to the fast memory node. So the accessing CPU and PID information are unnecessary for the slow memory pages. We can reuse these bits in struct page to record the scan time. For the fast memory pages, these bits are used as before. For the hot threshold, the default value is 1 second, which works well in our performance test. All pages with hint page fault latency < hot threshold will be considered hot. It's hard for users to determine the hot threshold. So we don't provide a kernel ABI to set it, just provide a debugfs interface for advanced users to experiment. We will continue to work on a hot threshold automatic adjustment mechanism. The downside of the above method is that the response time to the workload hot spot changing may be much longer. For example, - A previous cold memory area becomes hot - The hint page fault will be triggered. But the hint page fault latency isn't shorter than the hot threshold. So the pages will not be promoted. - When the memory area is scanned again, maybe after a scan period, the hint page fault latency measured will be shorter than the hot threshold and the pages will be promoted. To mitigate this, if there are enough free space in the fast memory node, the hot threshold will not be used, all pages will be promoted upon the hint page fault for fast response. Thanks Zhong Jiang reported and tested the fix for a bug when disabling memory tiering mode dynamically. Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.comSigned-off-by: -
Kefeng Wang authored
If a process has not enough memory to allocate a new virtual mapping, we may meet verious kinds of error, eg, fork cannot allocate memory, SIGBUS error in shmem, but it is difficult to confirm them, let's add some debug information to easily to check this scenario if __vm_enough_memory fails. Link: https://lkml.kernel.org/r/20220726145428.8030-1-wangkefeng.wang@huawei.comReported-by:
Yongqiang Liu <liuyongqiang13@huawei.com> Signed-off-by:
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Peter Collingbourne authored
gfp_migratetype() also expects GFP_RECLAIMABLE and GFP_MOVABLE|GFP_RECLAIMABLE to be shiftable into MIGRATE_* enum values, so add some more BUILD_BUG_ONs to reflect this assumption. Link: https://linux-review.googlesource.com/id/Iae64e2182f75c3aca776a486b71a72571d66d83e Link: https://lkml.kernel.org/r/20220726230241.3770532-1-pcc@google.comSigned-off-by:
Peter Collingbourne <pcc@google.com> Signed-off-by:
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Alistair Popple authored
When pinning pages with FOLL_LONGTERM check_and_migrate_movable_pages() is called to migrate pages out of zones which should not contain any longterm pinned pages. When migration succeeds all pages will have been unpinned so pinning needs to be retried. This is indicated by returning zero. When all pages are in the correct zone the number of pinned pages is returned. However migration can also fail, in which case pages are unpinned and -ENOMEM is returned. However if the failure was due to not being unable to isolate a page zero is returned. This leads to indefinite looping in __gup_longterm_locked(). Fix this by simplifying the return codes such that zero indicates all pages were successfully pinned in the correct zone while errors indicate either pages were migrated and pinning should be retried or that migration has failed and therefore the pinning operation should fail. [syoshida@redhat.com: fix return value for __gup_longterm_locked()] Link: https://lkml.kernel.org/r/20220821183547.950370-1-syoshida@redhat.com [akpm@linux-foundation.org: fix code layout, per John] [yshigeru@gmail.com: fix uninitialized return value on __gup_longterm_locked()] Link: https://lkml.kernel.org/r/20220827230037.78876-1-syoshida@redhat.com Link: https://lkml.kernel.org/r/20220729024645.764366-1-apopple@nvidia.comSigned-off-by:
Shigeru Yoshida <syoshida@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by:
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