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authorMuchun Song <songmuchun@bytedance.com>2022-06-28 17:22:29 +0800
committerAndrew Morton <akpm@linux-foundation.org>2022-08-08 18:06:42 -0700
commitcf5472e561133888df81d2e48f7da9ebd3299459 (patch)
tree9fa0200e74d8b9cb2ce833ffa8a86667bc67990f /mm
parent2da1c30929a28c3c6b01d9c16c4216037be95597 (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')
-rw-r--r--mm/hugetlb_vmemmap.c65
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,
},
{ }
};