diff options
author | Muchun Song <songmuchun@bytedance.com> | 2022-06-28 17:22:29 +0800 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2022-08-08 18:06:42 -0700 |
commit | cf5472e561133888df81d2e48f7da9ebd3299459 (patch) | |
tree | 9fa0200e74d8b9cb2ce833ffa8a86667bc67990f /mm/hugetlb_vmemmap.c | |
parent | 2da1c30929a28c3c6b01d9c16c4216037be95597 (diff) |
mm: hugetlb_vmemmap: optimize vmemmap_optimize_mode handling
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@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb_vmemmap.c')
-rw-r--r-- | mm/hugetlb_vmemmap.c | 65 |
1 files changed, 7 insertions, 58 deletions
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 1362feb3c6c9..e5b83a25c2fa 100644 --- a/mm/hugetlb_vmemmap.c +++ b/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 *h, struct page *head) 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 hstate *h) 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 hstate *h) } #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, }, { } }; |