- 04 Jul, 2024 40 commits
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Barry Song authored
For the !folio_test_anon(folio) case, we can now invoke folio_add_new_anon_rmap() with the rmap flags set to either EXCLUSIVE or non-EXCLUSIVE. This action will suppress the VM_WARN_ON_FOLIO check within __folio_add_anon_rmap() while initiating the process of bringing up mTHP swapin. static __always_inline void __folio_add_anon_rmap(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *vma, unsigned long address, rmap_t flags, enum rmap_level level) { ... if (unlikely(!folio_test_anon(folio))) { VM_WARN_ON_FOLIO(folio_test_large(folio) && level != RMAP_LEVEL_PMD, folio); } ... } It also improves the code's readability. Currently, all new anonymous folios calling folio_add_anon_rmap_ptes() are order-0. This ensures that new folios cannot be partially exclusive; they are either entirely exclusive or entirely shared. A useful comment from Hugh's fix: : Commit "mm: use folio_add_new_anon_rmap() if folio_test_anon(folio)== : false" has extended folio_add_new_anon_rmap() to use on non-exclusive : folios, already visible to others in swap cache and on LRU. : : That renders its non-atomic __folio_set_swapbacked() unsafe: it risks : overwriting concurrent atomic operations on folio->flags, losing bits : added or restoring bits cleared. Since it's only used in this risky way : when folio_test_locked and !folio_test_anon, many such races are excluded; : but, for example, isolations by folio_test_clear_lru() are vulnerable, and : setting or clearing active. : : It could just use the atomic folio_set_swapbacked(); but this function : does try to avoid atomics where it can, so use a branch instead: just : avoid setting swapbacked when it is already set, that is good enough. : (Swapbacked is normally stable once set: lazyfree can undo it, but only : later, when found anon in a page table.) : : This fixes a lot of instability under compaction and swapping loads: : assorted "Bad page"s, VM_BUG_ON_FOLIO()s, apparently even page double : frees - though I've not worked out what races could lead to the latter. [akpm@linux-foundation.org: comment fixes, per David and akpm] [v-songbaohua@oppo.com: lock the folio to avoid race] Link: https://lkml.kernel.org/r/20240622032002.53033-1-21cnbao@gmail.com [hughd@google.com: folio_add_new_anon_rmap() careful __folio_set_swapbacked()] Link: https://lkml.kernel.org/r/f3599b1d-8323-0dc5-e9e0-fdb3cfc3dd5a@google.com Link: https://lkml.kernel.org/r/20240617231137.80726-3-21cnbao@gmail.comSigned-off-by:Barry Song <v-songbaohua@oppo.com> Signed-off-by:
Hugh Dickins <hughd@google.com> Suggested-by:
David Hildenbrand <david@redhat.com> Tested-by:
Shuai Yuan <yuanshuai@oppo.com> Acked-by:
Andrew Morton <akpm@linux-foundation.org>
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Barry Song authored
Patch series "mm: clarify folio_add_new_anon_rmap() and __folio_add_anon_rmap()", v2. This patchset is preparatory work for mTHP swapin. folio_add_new_anon_rmap() assumes that new anon rmaps are always exclusive. However, this assumption doesn’t hold true for cases like do_swap_page(), where a new anon might be added to the swapcache and is not necessarily exclusive. The patchset extends the rmap flags to allow folio_add_new_anon_rmap() to handle both exclusive and non-exclusive new anon folios. The do_swap_page() function is updated to use this extended API with rmap flags. Consequently, all new anon folios now consistently use folio_add_new_anon_rmap(). The special case for !folio_test_anon() in __folio_add_anon_rmap() can be safely removed. In conclusion, new anon folios always use folio_add_new_anon_rmap(), regardless of exclusivity. Old anon folios continue to use __folio_add_anon_rmap() via folio_add_anon_rmap_pmd() and folio_add_anon_rmap_ptes(). This patch (of 3): In the case of a swap-in, a new anonymous folio is not necessarily exclusive. This patch updates the rmap flags to allow a new anonymous folio to be treated as either exclusive or non-exclusive. To maintain the existing behavior, we always use EXCLUSIVE as the default setting. [akpm@linux-foundation.org: cleanup and constifications per David and akpm] [v-songbaohua@oppo.com: fix missing doc for flags of folio_add_new_anon_rmap()] Link: https://lkml.kernel.org/r/20240619210641.62542-1-21cnbao@gmail.com [v-songbaohua@oppo.com: enhance doc for extend rmap flags arguments for folio_add_new_anon_rmap] Link: https://lkml.kernel.org/r/20240622030256.43775-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240617231137.80726-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240617231137.80726-2-21cnbao@gmail.comSigned-off-by:
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Shubhang Kaushik OS authored
'vmap allocation for size %lu failed: use vmalloc=<size> to increase size' The above warning is seen in the kernel functionality for allocation of the restricted virtual memory range till exhaustion. This message is misleading because 'vmalloc=' is supported on arm32, x86 platforms and is not a valid kernel parameter on a number of other platforms (in particular its not supported on arm64, alpha, loongarch, arc, csky, hexagon, microblaze, mips, nios2, openrisc, parisc, m64k, powerpc, riscv, sh, um, xtensa, s390, sparc). With the update, the output gets modified to include the function parameters along with the start and end of the virtual memory range allowed. The warning message after fix on kernel version 6.10.0-rc1+: vmalloc_node_range for size 33619968 failed: Address range restricted between 0xffff800082640000 - 0xffff800084650000 Backtrace with the misleading error message: vmap allocation for size 33619968 failed: use vmalloc=<size> to increase size insmod: vmalloc error: size 33554432, vm_struct allocation failed, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0 CPU: 46 PID: 1977 Comm: insmod Tainted: G E 6.10.0-rc1+ #79 Hardware name: INGRASYS Yushan Server iSystem TEMP-S000141176+10/Yushan Motherboard, BIOS 2.10.20230517 (SCP: xxx) yyyy/mm/dd Call trace: dump_backtrace+0xa0/0x128 show_stack+0x20/0x38 dump_stack_lvl+0x78/0x90 dump_stack+0x18/0x28 warn_alloc+0x12c/0x1b8 __vmalloc_node_range_noprof+0x28c/0x7e0 custom_init+0xb4/0xfff8 [test_driver] do_one_initcall+0x60/0x290 do_init_module+0x68/0x250 load_module+0x236c/0x2428 init_module_from_file+0x8c/0xd8 __arm64_sys_finit_module+0x1b4/0x388 invoke_syscall+0x78/0x108 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0x100/0x130 el0t_64_sync+0x190/0x198 [Shubhang@os.amperecomputing.com: v5] Link: https://lkml.kernel.org/r/CH2PR01MB5894B0182EA0B28DF2EFB916F5C72@CH2PR01MB5894.prod.exchangelabs.com Link: https://lkml.kernel.org/r/MN2PR01MB59025CC02D1D29516527A693F5C62@MN2PR01MB5902.prod.exchangelabs.comSigned-off-by:
Shubhang Kaushik <shubhang@os.amperecomputing.com> Reviewed-by:
Christoph Lameter (Ampere) <cl@linux.com> Cc: Christoph Lameter <cl@linux.com> Cc: Guo Ren <guoren@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Xiongwei Song <xiongwei.song@windriver.com> Signed-off-by:
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David Hildenbrand authored
We currently have a hack for virtio-mem in place to handle memory offlining with PageOffline pages for which we already adjusted the managed page count. Let's enlighten memory offlining code so we can get rid of that hack, and document the situation. Link: https://lkml.kernel.org/r/20240607090939.89524-4-david@redhat.comSigned-off-by:
Oscar Salvador <osalvador@suse.de> Cc: Alexander Potapenko <glider@google.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eugenio Pérez <eperezma@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Marco Elver <elver@google.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Signed-off-by:
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David Hildenbrand authored
We currently initialize the memmap such that PG_reserved is set and the refcount of the page is 1. In virtio-mem code, we have to manually clear that PG_reserved flag to make memory offlining with partially hotplugged memory blocks possible: has_unmovable_pages() would otherwise bail out on such pages. We want to avoid PG_reserved where possible and move to typed pages instead. Further, we want to further enlighten memory offlining code about PG_offline: offline pages in an online memory section. One example is handling managed page count adjustments in a cleaner way during memory offlining. So let's initialize the pages with PG_offline instead of PG_reserved. generic_online_page()->__free_pages_core() will now clear that flag before handing that memory to the buddy. Note that the page refcount is still 1 and would forbid offlining of such memory except when special care is take during GOING_OFFLINE as currently only implemented by virtio-mem. With this change, we can now get non-PageReserved() pages in the XEN balloon list. From what I can tell, that can already happen via decrease_reservation(), so that should be fine. HV-balloon should not really observe a change: partial online memory blocks still cannot get surprise-offlined, because the refcount of these PageOffline() pages is 1. Update virtio-mem, HV-balloon and XEN-balloon code to be aware that hotplugged pages are now PageOffline() instead of PageReserved() before they are handed over to the buddy. We'll leave the ZONE_DEVICE case alone for now. Note that self-hosted vmemmap pages will no longer be marked as reserved. This matches ordinary vmemmap pages allocated from the buddy during memory hotplug. Now, really only vmemmap pages allocated from memblock during early boot will be marked reserved. Existing PageReserved() checks seem to be handling all relevant cases correctly even after this change. Link: https://lkml.kernel.org/r/20240607090939.89524-3-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Patch series "mm/memory_hotplug: use PageOffline() instead of PageReserved() for !ZONE_DEVICE". This can be a considered a long-overdue follow-up to some parts of [1]. The patches are based on [2], but they are not strictly required -- just makes it clearer why we can use adjust_managed_page_count() for memory hotplug without going into details about highmem. We stop initializing pages with PageReserved() in memory hotplug code -- except when dealing with ZONE_DEVICE for now. Instead, we use PageOffline(): all pages are initialized to PageOffline() when onlining a memory section, and only the ones actually getting exposed to the system/page allocator will get PageOffline cleared. This way, we enlighten memory hotplug more about PageOffline() pages and can cleanup some hacks we have in virtio-mem code. What about ZONE_DEVICE? PageOffline() is wrong, but we might just stop using PageReserved() for them later by simply checking for is_zone_device_page() at suitable places. That will be a separate patch set / proposal. This primarily affects virtio-mem, HV-balloon and XEN balloon. I only briefly tested with virtio-mem, which benefits most from these cleanups. [1] https://lore.kernel.org/all/20191024120938.11237-1-david@redhat.com/ [2] https://lkml.kernel.org/r/20240607083711.62833-1-david@redhat.com This patch (of 3): In preparation for further changes, let's teach __free_pages_core() about the differences of memory hotplug handling. Move the memory hotplug specific handling from generic_online_page() to __free_pages_core(), use adjust_managed_page_count() on the memory hotplug path, and spell out why memory freed via memblock cannot currently use adjust_managed_page_count(). [david@redhat.com: add missed CONFIG_DEFERRED_STRUCT_PAGE_INIT] Link: https://lkml.kernel.org/r/b72e6efd-fb0a-459c-b1a0-88a98e5b19e2@redhat.com [david@redhat.com: fix up the memblock comment, per Oscar] Link: https://lkml.kernel.org/r/2ed64218-7f3b-4302-a5dc-27f060654fe2@redhat.com [david@redhat.com: add the parameter name also in the declaration] Link: https://lkml.kernel.org/r/ca575956-f0dd-4fb9-a307-6b7621681ed9@redhat.com Link: https://lkml.kernel.org/r/20240607090939.89524-1-david@redhat.com Link: https://lkml.kernel.org/r/20240607090939.89524-2-david@redhat.comSigned-off-by:
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Kefeng Wang authored
There are no more users of page_mkclean(), remove it and update the document and comment. Link: https://lkml.kernel.org/r/20240604114822.2089819-5-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by:
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Kefeng Wang authored
Replaces three calls to compound_head() with one, which removes last caller of page_mkclean(). Link: https://lkml.kernel.org/r/20240604114822.2089819-4-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
After the last user of page_maybe_dma_pinned() is converted to folio_maybe_dma_pinned(), remove page_maybe_dma_pinned() and update the document and comment. [wangkefeng.wang@huawei.com: fix pin_user_pages.rst underlining] Link: https://lkml.kernel.org/r/61b256c7-4989-44ec-83db-f34a1bd4be2d@huawei.com Link: https://lkml.kernel.org/r/20240604114822.2089819-3-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Patch series "mm: remove page_maybe_dma_pinned() and page_mkclean()". Most page_maybe_dma_pinned() and page_mkclean() callers have been converted to the folio equivalents, after two more convertsions, remove them and update the comment and documention. This patch (of 4): Convert to use vm_normal_folio() and folio_maybe_dma_pinned() API, which helps to remove page_maybe_dma_pinned() in the subsequent change. Link: https://lkml.kernel.org/r/20240604114822.2089819-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240604114822.2089819-2-wangkefeng.wang@huawei.comSigned-off-by:
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David Hildenbrand authored
Let's simply reinitialize the page->_mapcount directly. We can now get rid of page_mapcount_reset(). Link: https://lkml.kernel.org/r/20240529111904.2069608-7-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Let's get rid of the page_mapcount_reset() call and simply reinitialize folio->_mapcount directly. Link: https://lkml.kernel.org/r/20240529111904.2069608-6-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Let's stop using page_mapcount_reset() and clear PageBuddy using __ClearPageBuddy() instead. Link: https://lkml.kernel.org/r/20240529111904.2069608-5-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Let's clean it up: use a proper page type and store our data (offset into a page) in the lower 16 bit as documented. We won't be able to support 256 KiB base pages, which is acceptable. Teach Kconfig to handle that cleanly using a new CONFIG_HAVE_ZSMALLOC. Based on this, we should do a proper "struct zsdesc" conversion, as proposed in [1]. This removes the last _mapcount/page_type offender. [1] https://lore.kernel.org/all/20231130101242.2590384-1-42.hyeyoo@gmail.com/ Link: https://lkml.kernel.org/r/20240529111904.2069608-4-david@redhat.comSigned-off-by:
Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by:
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David Hildenbrand authored
As long as the owner sets a page type first, we can allow reuse of the lower 16 bit: sufficient to store an offset into a 64 KiB page, which is the maximum base page size in *common* configurations (ignoring the 256 KiB variant). Restrict it to the head page. We'll use that for zsmalloc next, to set a proper type while still reusing that field to store information (offset into a base page) that cannot go elsewhere for now. Let's reserve the lower 16 bit for that purpose and for catching mapcount underflows, and let's reduce PAGE_TYPE_BASE to a single bit. Note that we will still have to overflow the mapcount quite a lot until we would actually indicate a valid page type. Start handing out the type bits from highest to lowest, to make it clearer how many bits for types we have left. Out of 15 bit we can use for types, we currently use 6. If we run out of bits before we have better typing (e.g., memdesc), we can always investigate storing a value instead [1]. [1] https://lore.kernel.org/all/00ba1dff-7c05-46e8-b0d9-a78ac1cfc198@redhat.com/ [akpm@linux-foundation.org: fix PG_hugetlb typo, per David] Link: https://lkml.kernel.org/r/20240529111904.2069608-3-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Patch series "mm: page_type, zsmalloc and page_mapcount_reset()", v2. Wanting to remove the remaining abuser of _mapcount/page_type along with page_mapcount_reset(), I stumbled over zsmalloc, which is yet to be converted away from "struct page" [1]. Unfortunately, we cannot stop using the page_type field in zsmalloc code completely for its own purposes. All other fields in "struct page" are used one way or the other. Could we simply store a 2-byte offset value at the beginning of each page? Likely, but that will require a bit more work; and once we have memdesc we might want to move the offset in there (struct zsalloc?) again. ... but we can limit the abuse to 16 bit, glue it to a page type that must be set, and document it. page_has_type() will always successfully indicate such zsmalloc pages, and such zsmalloc pages only. We lose zsmalloc support for PAGE_SIZE > 64KB, which should be tolerable. We could use more bits from the page type, but 16 bit sounds like a good idea for now. So clarify the _mapcount/page_type documentation, use a proper page_type for zsmalloc, and remove page_mapcount_reset(). [1] https://lore.kernel.org/all/20231130101242.2590384-1-42.hyeyoo@gmail.com/ This patch (of 6): Let's make it clearer that _mapcount must no longer be used for own purposes, and how _mapcount and page_type behaves nowadays (also in the context of hugetlb folios, which are typed folios that will be mapped to user space). Move the documentation regarding "-1" over from page_mapcount_reset(), which we will remove next. Move "page_type" before "mapcount", to make it clearer what typed folios are. Link: https://lkml.kernel.org/r/20240529111904.2069608-1-david@redhat.com Link: https://lkml.kernel.org/r/20240529111904.2069608-2-david@redhat.comSigned-off-by:
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John Hubbard authored
This continues the work on getting the selftests to build without requiring people to first run "make headers" [1]. Now that the system call numbers are in the correct, checked-in locations in the kernel tree (./tools/include/uapi/asm/unistd*.h), make sure that the mm selftests include that file (indirectly). Doing so provides guaranteed definitions at build time, so remove all of the checks for "ifdef __NR_xxx" in the mm selftests, because they will always be true (defined). [1] commit e076eaca ("selftests: break the dependency upon local header files") Link: https://lkml.kernel.org/r/20240618022422.804305-7-jhubbard@nvidia.comSigned-off-by:
John Hubbard <jhubbard@nvidia.com> Acked-by:
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Andrew Morton authored
Fix used-uninitialized of `page'. Fixes: dce7d10b ("mm/madvise: optimize lazyfreeing with mTHP in madvise_free") Reported-by:
kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406260514.SLhNM9kQ-lkp@intel.com Cc: Lance Yang <ioworker0@gmail.com> Signed-off-by:
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Ryusuke Konishi authored
If the bitmap block that manages the inode allocation status is corrupted, nilfs_ifile_create_inode() may allocate a new inode from the reserved inode area where it should not be allocated. Previous fix commit d325dc6e ("nilfs2: fix use-after-free bug of struct nilfs_root"), fixed the problem that reserved inodes with inode numbers less than NILFS_USER_INO (=11) were incorrectly reallocated due to bitmap corruption, but since the start number of non-reserved inodes is read from the super block and may change, in which case inode allocation may occur from the extended reserved inode area. If that happens, access to that inode will cause an IO error, causing the file system to degrade to an error state. Fix this potential issue by adding a wraparound option to the common metadata object allocation routine and by modifying nilfs_ifile_create_inode() to disable the option so that it only allocates inodes with inode numbers greater than or equal to the inode number read in "nilfs->ns_first_ino", regardless of the bitmap status of reserved inodes. Link: https://lkml.kernel.org/r/20240623051135.4180-4-konishi.ryusuke@gmail.comSigned-off-by:
Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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Ryusuke Konishi authored
Syzbot reported that mounting and unmounting a specific pattern of corrupted nilfs2 filesystem images causes a use-after-free of metadata file inodes, which triggers a kernel bug in lru_add_fn(). As Jan Kara pointed out, this is because the link count of a metadata file gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(), tries to delete that inode (ifile inode in this case). The inconsistency occurs because directories containing the inode numbers of these metadata files that should not be visible in the namespace are read without checking. Fix this issue by treating the inode numbers of these internal files as errors in the sanity check helper when reading directory folios/pages. Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer analysis. Link: https://lkml.kernel.org/r/20240623051135.4180-3-konishi.ryusuke@gmail.comSigned-off-by:
Jan Kara <jack@suse.cz> Closes: https://lkml.kernel.org/r/20240617075758.wewhukbrjod5fp5o@quack3Tested-by:
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Ryusuke Konishi authored
Patch series "nilfs2: fix potential issues related to reserved inodes". This series fixes one use-after-free issue reported by syzbot, caused by nilfs2's internal inode being exposed in the namespace on a corrupted filesystem, and a couple of flaws that cause problems if the starting number of non-reserved inodes written in the on-disk super block is intentionally (or corruptly) changed from its default value. This patch (of 3): In the current implementation of nilfs2, "nilfs->ns_first_ino", which gives the first non-reserved inode number, is read from the superblock, but its lower limit is not checked. As a result, if a number that overlaps with the inode number range of reserved inodes such as the root directory or metadata files is set in the super block parameter, the inode number test macros (NILFS_MDT_INODE and NILFS_VALID_INODE) will not function properly. In addition, these test macros use left bit-shift calculations using with the inode number as the shift count via the BIT macro, but the result of a shift calculation that exceeds the bit width of an integer is undefined in the C specification, so if "ns_first_ino" is set to a large value other than the default value NILFS_USER_INO (=11), the macros may potentially malfunction depending on the environment. Fix these issues by checking the lower bound of "nilfs->ns_first_ino" and by preventing bit shifts equal to or greater than the NILFS_USER_INO constant in the inode number test macros. Also, change the type of "ns_first_ino" from signed integer to unsigned integer to avoid the need for type casting in comparisons such as the lower bound check introduced this time. Link: https://lkml.kernel.org/r/20240623051135.4180-1-konishi.ryusuke@gmail.com Link: https://lkml.kernel.org/r/20240623051135.4180-2-konishi.ryusuke@gmail.comSigned-off-by:
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Jan Kara authored
The dirty throttling logic is interspersed with assumptions that dirty limits in PAGE_SIZE units fit into 32-bit (so that various multiplications fit into 64-bits). If limits end up being larger, we will hit overflows, possible divisions by 0 etc. Fix these problems by never allowing so large dirty limits as they have dubious practical value anyway. For dirty_bytes / dirty_background_bytes interfaces we can just refuse to set so large limits. For dirty_ratio / dirty_background_ratio it isn't so simple as the dirty limit is computed from the amount of available memory which can change due to memory hotplug etc. So when converting dirty limits from ratios to numbers of pages, we just don't allow the result to exceed UINT_MAX. This is root-only triggerable problem which occurs when the operator sets dirty limits to >16 TB. Link: https://lkml.kernel.org/r/20240621144246.11148-2-jack@suse.czSigned-off-by:
Zach O'Keefe <zokeefe@google.com> Reviewed-By:
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Jan Kara authored
Patch series "mm: Avoid possible overflows in dirty throttling". Dirty throttling logic assumes dirty limits in page units fit into 32-bits. This patch series makes sure this is true (see patch 2/2 for more details). This patch (of 2): This reverts commit 9319b647. The commit is broken in several ways. Firstly, the removed (u64) cast from the multiplication will introduce a multiplication overflow on 32-bit archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the default settings with 4GB of RAM will trigger this). Secondly, the div64_u64() is unnecessarily expensive on 32-bit archs. We have div64_ul() in case we want to be safe & cheap. Thirdly, if dirty thresholds are larger than 1<<32 pages, then dirty balancing is going to blow up in many other spectacular ways anyway so trying to fix one possible overflow is just moot. Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz Fixes: 9319b647 ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again") Signed-off-by:
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Jinliang Zheng authored
When mm_update_owner_next() is racing with swapoff (try_to_unuse()) or /proc or ptrace or page migration (get_task_mm()), it is impossible to find an appropriate task_struct in the loop whose mm_struct is the same as the target mm_struct. If the above race condition is combined with the stress-ng-zombie and stress-ng-dup tests, such a long loop can easily cause a Hard Lockup in write_lock_irq() for tasklist_lock. Recognize this situation in advance and exit early. Link: https://lkml.kernel.org/r/20240620122123.3877432-1-alexjlzheng@tencent.comSigned-off-by:
Jinliang Zheng <alexjlzheng@tencent.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tycho Andersen <tandersen@netflix.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Hongfu Li authored
Use the new KMEM_CACHE() macro instead of direct kmem_cache_create to simplify the creation of SLAB caches. Link: https://lkml.kernel.org/r/20240618014517.25954-1-lihongfu@kylinos.cnSigned-off-by:
Hongfu Li <lihongfu@kylinos.cn> Acked-by:
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Kefeng Wang authored
After commit 21fbd591 ("ksm: add the ksm prefix to the names of the ksm private structures"), we could directly use KMEM_CACHE(). Link: https://lkml.kernel.org/r/20240618081201.134985-1-wangkefeng.wang@huawei.comSigned-off-by:
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SeongJae Park authored
DAMON_LRU_SORT contains code for handling of online DAMON parameters update edge cases. It is no more necessary since damon_commit_ctx() takes care of the cases. Remove the unnecessary code. Link: https://lkml.kernel.org/r/20240618181809.82078-13-sj@kernel.orgSigned-off-by:
SeongJae Park <sj@kernel.org> Signed-off-by:
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SeongJae Park authored
DAMON_LRU_SORT manually manipulates the DAMON context struct for online parameters update. Since the struct contains not only input parameters but also internal status and operation results, it is not that simple. Indeed, we found and fixed a few bugs in the code. Now DAMON core layer provides a function for the usage, namely damon_commit_ctx(). Replace the manual manipulation logic with the function. The core layer function could have its own bugs, but this change removes a source of bugs. Link: https://lkml.kernel.org/r/20240618181809.82078-12-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
DAMON_RECLAIM contains code for handling of online DAMON parameters update edge cases. It is no more necessary since damon_commit_ctx() takes care of the cases. Remove the unnecessary code. Link: https://lkml.kernel.org/r/20240618181809.82078-11-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
DAMON_RECLAIM manually manipulates the DAMON context struct for online parameters update. Since the struct contains not only input parameters but also internal status and operation results, it is not that simple. Indeed, we found and fixed a few bugs in the code. Now DAMON core layer provides a function for the usage, namely damon_commit_ctx(). Replace the manual manipulation logic with the function. The core layer function could have its own bugs, but this change removes a source of bugs. Link: https://lkml.kernel.org/r/20240618181809.82078-10-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
The functions were for updating DAMON structs that may or may not be partially populated. Hence it was not for only adding items, but also removing unnecessary items and updating items in-place. A previous commit has changed the functions to assume the structs are not partially populated, and do only adding items. Make the names better explain the behavior. Link: https://lkml.kernel.org/r/20240618181809.82078-9-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
damon/sysfs-schemes.c contains code for handling of online DAMON parameters update edge cases. The logics are no more necessary since damon_commit_ctx() and damon_commit_quota_goals() takes care of the cases. Remove the unnecessary code. Link: https://lkml.kernel.org/r/20240618181809.82078-8-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
The function was for updating DAMON structs that may or may not be partially populated. Hence it was not for only adding items, but also removing unnecessary items and updating items in-place. A previous commit has changed the function to assume the structs are not partially populated, and do only adding items. Make the function name better explain the behavior. Link: https://lkml.kernel.org/r/20240618181809.82078-7-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
damon/sysfs.c contains code for handling of online DAMON parameters update edge cases. It is no more necessary since damon_commit_ctx() takes care of the cases. Remove the unnecessary code. Link: https://lkml.kernel.org/r/20240618181809.82078-6-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
DAMON_SYSFS manually manipulates the DAMOS quota structs for online quotal goals parameter update. Since the struct contains not only input parameters but also internal status and operation results, it is not that simple. Now DAMON core layer provides a function for the usage, namely damon_commit_quota_goals(). Replace the manual manipulation logic with the function. The core layer function could have its own bugs, but this change removes a source of bugs. Link: https://lkml.kernel.org/r/20240618181809.82078-5-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
DAMON_SYSFS manually manipulates DAMON context structs for online parameters update. Since the struct contains not only input parameters but also internal status and operation results, it is not that simple. Indeed, we found and fixed a few bugs in the code. Now DAMON core layer provides a function for the usage, namely damon_commit_ctx(). Replace the manual manipulation logic with the function. The core layer function could have its own bugs, but this change removes a source of bugs. Link: https://lkml.kernel.org/r/20240618181809.82078-4-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Implement functions for supporting online DAMON context level parameters update. The function receives two DAMON context structs. One is the struct that currently being used by a kdamond and therefore to be updated. The other one contains the parameters to be applied to the first one. The function applies the new parameters to the destination struct while keeping/updating the internal status and operation results. The function should be called from DAMON context-update-safe place, like DAMON callbacks. Link: https://lkml.kernel.org/r/20240618181809.82078-3-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Patch series "mm/damon: introduce DAMON parameters online commit function". DAMON context struct (damon_ctx) contains user requests (parameters), internal status, and operation results. For flexible usages, DAMON API users are encouraged to manually manipulate the struct. That works well for simple use cases. However, it has turned out that it is not that simple at least for online parameters udpate. It is easy to forget properly maintaining internal status and operation results. Also, such manual manipulation for online tuning is implemented multiple times on DAMON API users including DAMON sysfs interface, DAMON_RECLAIM and DAMON_LRU_SORT. As a result, we have multiple sources of bugs for same problem. Actually we found and fixed a few bugs from online parameter updating of DAMON API users. Implement a function for online DAMON parameters update in core layer, and replace DAMON API users' manual manipulation code for the use case. The core layer function could still have bugs, but this change reduces the source of bugs for the problem to one place. This patch (of 12): Implement functions for supporting online DAMOS quota goals parameters update. The function receives two DAMOS quota structs. One is the struct that currently being used by a kdamond and therefore to be updated. The other one contains the parameters to be applied to the first one. The function applies the new parameters to the destination struct while keeping/updating the internal status. The function should be called from parameters-update safe place, like DAMON callbacks. Link: https://lkml.kernel.org/r/20240618181809.82078-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240618181809.82078-2-sj@kernel.orgSigned-off-by:
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Baolin Wang authored
mem_cgroup_migrate() will clear the memcg data of the old folio, therefore, the callers must make sure the old folio is no longer on the LRU list, otherwise the old folio can not get the correct lruvec object without the memcg data, which could lead to potential problems [1]. Thus adding a VM_BUG_ON_FOLIO() to catch this issue. [1] https://lore.kernel.org/all/5ab860d8ee987955e917748f9d6da525d3b52690.1718326003.git.baolin.wang@linux.alibaba.com/ Link: https://lkml.kernel.org/r/66d181c41b7ced35dbd39ffd3f5774a11aef266a.1718327124.git.baolin.wang@linux.alibaba.comSigned-off-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Suggested-by:
Shakeel Butt <shakeel.butt@linux.dev> Acked-by:
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Honggyu Kim authored
This patch adds damon description for "migrate_hot" and "migrate_cold" actions for both usage and design documents as long as a new "target_nid" knob to set the migration target node. [sj@kernel.org: trivial fixups for DAMOS_MIGRATE_{HOT,COLD} documentation] Link: https://lkml.kernel.org/r/20240618213630.84846-2-sj@kernel.org Link: https://lkml.kernel.org/r/20240614030010.751-8-honggyu.kim@sk.comSigned-off-by:Honggyu Kim <honggyu.kim@sk.com> Signed-off-by:
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