The patch titled Subject: mm: hugetlb_vmemmap: optimize vmemmap_optimize_mode handling has been added to the -mm mm-unstable branch. Its filename is mm-hugetlb_vmemmap-optimize-vmemmap_optimize_mode-handling.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-optimize-vmemmap_optimize_mode-handling.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Muchun Song <songmuchun@xxxxxxxxxxxxx> Subject: mm: hugetlb_vmemmap: optimize vmemmap_optimize_mode handling Date: Tue, 28 Jun 2022 17:22:29 +0800 We hold an another reference to hugetlb_optimize_vmemmap_key when making vmemmap_optimize_mode on, because we use static_key to tell memory_hotplug that memory_hotplug.memmap_on_memory should be overridden. However, this rule has gone when we have introduced PageVmemmapSelfHosted. Therefore, we could simplify vmemmap_optimize_mode handling by not holding an another reference to hugetlb_optimize_vmemmap_key. This also means that we not incur the extra page_fixed_fake_head checks if there are no vmemmap optinmized hugetlb pages after this change. Link: https://lkml.kernel.org/r/20220628092235.91270-3-songmuchun@xxxxxxxxxxxxx Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page-flags.h | 6 +-- mm/hugetlb_vmemmap.c | 65 +++-------------------------------- 2 files changed, 9 insertions(+), 62 deletions(-) --- a/include/linux/page-flags.h~mm-hugetlb_vmemmap-optimize-vmemmap_optimize_mode-handling +++ a/include/linux/page-flags.h @@ -205,8 +205,7 @@ enum pageflags { #ifndef __GENERATING_BOUNDS_H #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP -DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON, - hugetlb_optimize_vmemmap_key); +DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); /* * If the feature of optimizing vmemmap pages associated with each HugeTLB @@ -226,8 +225,7 @@ DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_ */ static __always_inline const struct page *page_fixed_fake_head(const struct page *page) { - if (!static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON, - &hugetlb_optimize_vmemmap_key)) + if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) return page; /* --- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-optimize-vmemmap_optimize_mode-handling +++ a/mm/hugetlb_vmemmap.c @@ -23,42 +23,15 @@ #define RESERVE_VMEMMAP_NR 1U #define RESERVE_VMEMMAP_SIZE (RESERVE_VMEMMAP_NR << PAGE_SHIFT) -enum vmemmap_optimize_mode { - VMEMMAP_OPTIMIZE_OFF, - VMEMMAP_OPTIMIZE_ON, -}; - -DEFINE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON, - hugetlb_optimize_vmemmap_key); +DEFINE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key); -static enum vmemmap_optimize_mode vmemmap_optimize_mode = +static bool vmemmap_optimize_enabled = IS_ENABLED(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON); -static void vmemmap_optimize_mode_switch(enum vmemmap_optimize_mode to) -{ - if (vmemmap_optimize_mode == to) - return; - - if (to == VMEMMAP_OPTIMIZE_OFF) - static_branch_dec(&hugetlb_optimize_vmemmap_key); - else - static_branch_inc(&hugetlb_optimize_vmemmap_key); - WRITE_ONCE(vmemmap_optimize_mode, to); -} - static int __init hugetlb_vmemmap_early_param(char *buf) { - bool enable; - enum vmemmap_optimize_mode mode; - - if (kstrtobool(buf, &enable)) - return -EINVAL; - - mode = enable ? VMEMMAP_OPTIMIZE_ON : VMEMMAP_OPTIMIZE_OFF; - vmemmap_optimize_mode_switch(mode); - - return 0; + return kstrtobool(buf, &vmemmap_optimize_enabled); } early_param("hugetlb_free_vmemmap", hugetlb_vmemmap_early_param); @@ -100,7 +73,7 @@ int hugetlb_vmemmap_alloc(struct hstate static unsigned int vmemmap_optimizable_pages(struct hstate *h, struct page *head) { - if (READ_ONCE(vmemmap_optimize_mode) == VMEMMAP_OPTIMIZE_OFF) + if (!READ_ONCE(vmemmap_optimize_enabled)) return 0; if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) { @@ -191,7 +164,6 @@ void __init hugetlb_vmemmap_init(struct if (!is_power_of_2(sizeof(struct page))) { pr_warn_once("cannot optimize vmemmap pages because \"struct page\" crosses page boundaries\n"); - static_branch_disable(&hugetlb_optimize_vmemmap_key); return; } @@ -212,36 +184,13 @@ void __init hugetlb_vmemmap_init(struct } #ifdef CONFIG_PROC_SYSCTL -static int hugetlb_optimize_vmemmap_handler(struct ctl_table *table, int write, - void *buffer, size_t *length, - loff_t *ppos) -{ - int ret; - enum vmemmap_optimize_mode mode; - static DEFINE_MUTEX(sysctl_mutex); - - if (write && !capable(CAP_SYS_ADMIN)) - return -EPERM; - - mutex_lock(&sysctl_mutex); - mode = vmemmap_optimize_mode; - table->data = &mode; - ret = proc_dointvec_minmax(table, write, buffer, length, ppos); - if (write && !ret) - vmemmap_optimize_mode_switch(mode); - mutex_unlock(&sysctl_mutex); - - return ret; -} - static struct ctl_table hugetlb_vmemmap_sysctls[] = { { .procname = "hugetlb_optimize_vmemmap", - .maxlen = sizeof(enum vmemmap_optimize_mode), + .data = &vmemmap_optimize_enabled, + .maxlen = sizeof(int), .mode = 0644, - .proc_handler = hugetlb_optimize_vmemmap_handler, - .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, + .proc_handler = proc_dobool, }, { } }; _ Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are mm-sparsemem-fix-missing-higher-order-allocation-splitting.patch mm-memory_hotplug-enumerate-all-supported-section-flags.patch mm-memory_hotplug-enumerate-all-supported-section-flags-v5.patch mm-memory_hotplug-make-hugetlb_optimize_vmemmap-compatible-with-memmap_on_memory.patch mm-memory_hotplug-make-hugetlb_optimize_vmemmap-compatible-with-memmap_on_memory-v5.patch mm-hugetlb-remove-minimum_order-variable.patch mm-memcontrol-remove-dead-code-and-comments.patch mm-rename-unlock_page_lruvec_irq-_irqrestore-to-lruvec_unlock_irq-_irqrestore.patch mm-memcontrol-prepare-objcg-api-for-non-kmem-usage.patch mm-memcontrol-make-lruvec-lock-safe-when-lru-pages-are-reparented.patch mm-vmscan-rework-move_pages_to_lru.patch mm-thp-make-split-queue-lock-safe-when-lru-pages-are-reparented.patch mm-memcontrol-make-all-the-callers-of-foliopage_memcg-safe.patch mm-memcontrol-introduce-memcg_reparent_ops.patch mm-memcontrol-use-obj_cgroup-apis-to-charge-the-lru-pages.patch mm-lru-add-vm_warn_on_once_folio-to-lru-maintenance-function.patch mm-hugetlb_vmemmap-delete-hugetlb_optimize_vmemmap_enabled.patch mm-hugetlb_vmemmap-optimize-vmemmap_optimize_mode-handling.patch mm-hugetlb_vmemmap-introduce-the-name-hvo.patch mm-hugetlb_vmemmap-move-vmemmap-code-related-to-hugetlb-to-hugetlb_vmemmapc.patch mm-hugetlb_vmemmap-replace-early_param-with-core_param.patch mm-hugetlb_vmemmap-improve-hugetlb_vmemmap-code-readability.patch mm-hugetlb_vmemmap-move-code-comments-to-vmemmap_deduprst.patch mm-hugetlb_vmemmap-use-ptrs_per_pte-instead-of-pmd_size-page_size.patch