linux/mm/memory_hotplug.c, branch v6.3

mm/memory_hotplug: cleanup return value handing in do_migrate_range()

2023-02-20T20:46:18Z

Return value mechanism of do_migrate_range() is not very simple, while no caller of the function checks the return value. Make the function return nothing to be more simple, and cleanup related unnecessary code. Link: https://lkml.kernel.org/r/20230216170703.64574-1-sj@kernel.org Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Reviewed-by: Baolin Wang Signed-off-by: SeongJae Park Cc: Oscar Salvador Signed-off-by: Andrew Morton

mm: change to return bool for isolate_movable_page()

2023-02-20T20:46:17Z

Now the isolate_movable_page() can only return 0 or -EBUSY, and no users will care about the negative return value, thus we can convert the isolate_movable_page() to return a boolean value to make the code more clear when checking the movable page isolation state. No functional changes intended. [akpm@linux-foundation.org: remove unneeded comment, per Matthew] Link: https://lkml.kernel.org/r/cb877f73f4fff8d309611082ec740a7065b1ade0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

mm: change to return bool for isolate_lru_page()

2023-02-20T20:46:17Z

The isolate_lru_page() can only return 0 or -EBUSY, and most users did not care about the negative error of isolate_lru_page(), except one user in add_page_for_migration(). So we can convert the isolate_lru_page() to return a boolean value, which can help to make the code more clear when checking the return value of isolate_lru_page(). Also convert all users' logic of checking the isolation state. No functional changes intended. Link: https://lkml.kernel.org/r/3074c1ab628d9dbf139b33f248a8bc253a3f95f0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

mm/hugetlb: convert isolate_hugetlb to folios

2023-02-13T23:54:26Z

Patch series "continue hugetlb folio conversion", v3. This series continues the conversion of core hugetlb functions to use folios. This series converts many helper funtions in the hugetlb fault path. This is in preparation for another series to convert the hugetlb fault code paths to operate on folios. This patch (of 8): Convert isolate_hugetlb() to take in a folio and convert its callers to pass a folio. Use page_folio() to convert the callers to use a folio is safe as isolate_hugetlb() operates on a head page. Link: https://lkml.kernel.org/r/20230113223057.173292-1-sidhartha.kumar@oracle.com Link: https://lkml.kernel.org/r/20230113223057.173292-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Mike Kravetz Cc: John Hubbard Cc: Matthew Wilcox Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton

mm: add pageblock_aligned() macro

2022-10-03T21:03:04Z

Add pageblock_aligned() and use it to simplify code. Link: https://lkml.kernel.org/r/20220907060844.126891-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: Mike Rapoport Cc: David Hildenbrand Cc: Oscar Salvador Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: fix null-ptr-deref in kswapd_is_running()

2022-09-12T03:26:04Z

kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with kswapd_is_running() in kcompactd(), kswapd_run/stop() kcompactd() kswapd_is_running() pgdat->kswapd // error or nomal ptr verify pgdat->kswapd // load non-NULL pgdat->kswapd pgdat->kswapd = NULL task_is_running(pgdat->kswapd) // Null pointer derefence KASAN reports the null-ptr-deref shown below, vmscan: Failed to start kswapd on node 0 ... BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504 Read of size 8 at addr 0000000000000024 by task kcompactd0/37 CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x394 show_stack+0x34/0x4c dump_stack+0x158/0x1e4 __kasan_report+0x138/0x140 kasan_report+0x44/0xdc __asan_load8+0x94/0xd0 kcompactd+0x440/0x504 kthread+0x1a4/0x1f0 ret_from_fork+0x10/0x18 At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected by mem_hotplug_begin/done(), but without kcompactd(). There is no need to involve memory hotplug lock in kcompactd(), so let's add a new mutex to protect pgdat->kswapd accesses. Also, because the kcompactd task will check the state of kswapd task, it's better to call kcompactd_stop() before kswapd_stop() to reduce lock conflicts. [akpm@linux-foundation.org: add comments] Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Muchun Song Signed-off-by: Andrew Morton

mm: kill is_memblock_offlined()

2022-09-12T03:26:04Z

Directly check state of struct memory_block, no need a single function. Link: https://lkml.kernel.org/r/20220827112043.187028-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Reviewed-by: Anshuman Khandual Signed-off-by: Andrew Morton

mm: use is_zone_movable_page() helper

2022-07-30T01:07:20Z

Use is_zone_movable_page() helper to simplify code. Link: https://lkml.kernel.org/r/20220726131135.146912-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: David Hildenbrand Reviewed-by: Pankaj Gupta Acked-by: Jason Wang Signed-off-by: Andrew Morton

mm: memory_hotplug: make hugetlb_optimize_vmemmap compatible with memmap_on_memory

2022-07-04T01:08:49Z

For now, the feature of hugetlb_free_vmemmap is not compatible with the feature of memory_hotplug.memmap_on_memory, and hugetlb_free_vmemmap takes precedence over memory_hotplug.memmap_on_memory. However, someone wants to make memory_hotplug.memmap_on_memory takes precedence over hugetlb_free_vmemmap since memmap_on_memory makes it more likely to succeed memory hotplug in close-to-OOM situations. So the decision of making hugetlb_free_vmemmap take precedence is not wise and elegant. The proper approach is to have hugetlb_vmemmap.c do the check whether the section which the HugeTLB pages belong to can be optimized. If the section's vmemmap pages are allocated from the added memory block itself, hugetlb_free_vmemmap should refuse to optimize the vmemmap, otherwise, do the optimization. Then both kernel parameters are compatible. So this patch introduces VmemmapSelfHosted to mask any non-optimizable vmemmap pages. The hugetlb_vmemmap can use this flag to detect if a vmemmap page can be optimized. [songmuchun@bytedance.com: walk vmemmap page tables to avoid false-positive] Link: https://lkml.kernel.org/r/20220620110616.12056-3-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220617135650.74901-3-songmuchun@bytedance.com Signed-off-by: Muchun Song Co-developed-by: Oscar Salvador Signed-off-by: Oscar Salvador Acked-by: David Hildenbrand Cc: Jonathan Corbet Cc: Mike Kravetz Cc: Paul E. McKenney Cc: Xiongchun Duan Signed-off-by: Andrew Morton

mm: memory_hotplug: enumerate all supported section flags

2022-07-04T01:08:49Z

Patch series "make hugetlb_optimize_vmemmap compatible with memmap_on_memory", v3. This series makes hugetlb_optimize_vmemmap compatible with memmap_on_memory. This patch (of 2): We are almost running out of section flags, only one bit is available in the worst case (powerpc with 256k pages). However, there are still some free bits (in ->section_mem_map) on other architectures (e.g. x86_64 has 10 bits available, arm64 has 8 bits available with worst case of 64K pages). We have hard coded those numbers in code, it is inconvenient to use those bits on other architectures except powerpc. So transfer those section flags to enumeration to make it easy to add new section flags in the future. Also, move SECTION_TAINT_ZONE_DEVICE into the scope of CONFIG_ZONE_DEVICE to save a bit on non-zone-device case. [songmuchun@bytedance.com: replace enum with defines per David] Link: https://lkml.kernel.org/r/20220620110616.12056-2-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220617135650.74901-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220617135650.74901-2-songmuchun@bytedance.com Signed-off-by: Muchun Song Reviewed-by: David Hildenbrand Cc: Jonathan Corbet Cc: Mike Kravetz Cc: Oscar Salvador Cc: Paul E. McKenney Cc: Xiongchun Duan Signed-off-by: Andrew Morton