diff options
author | Andy Lutomirski <luto@kernel.org> | 2017-10-14 19:59:51 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-10-18 16:25:02 +0300 |
commit | 7ac7f2c315ef76437f5119df354d334448534fb5 (patch) | |
tree | 8fa734ab66ca99b3c38b0f56dacb44d6bc8da641 /arch/x86/mm | |
parent | 4e57b94664fef55aa71cac33b4632fdfdd52b695 (diff) | |
download | linux-7ac7f2c315ef76437f5119df354d334448534fb5.tar.xz |
x86/mm: Remove debug/x86/tlb_defer_switch_to_init_mm
Borislav thinks that we don't need this knob in a released kernel.
Get rid of it.
Requested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: b956575bed91 ("x86/mm: Flush more aggressively in lazy TLB mode")
Link: http://lkml.kernel.org/r/1fa72431924e81e86c164ff7881bf9240d1f1a6c.1508000261.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/tlb.c | 58 |
1 files changed, 0 insertions, 58 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 5ee3b59baa85..0f3d0cea4d00 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -30,7 +30,6 @@ atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1); -DEFINE_STATIC_KEY_TRUE(__tlb_defer_switch_to_init_mm); static void choose_new_asid(struct mm_struct *next, u64 next_tlb_gen, u16 *new_asid, bool *need_flush) @@ -629,60 +628,3 @@ static int __init create_tlb_single_page_flush_ceiling(void) return 0; } late_initcall(create_tlb_single_page_flush_ceiling); - -static ssize_t tlblazy_read_file(struct file *file, char __user *user_buf, - size_t count, loff_t *ppos) -{ - char buf[2]; - - buf[0] = static_branch_likely(&__tlb_defer_switch_to_init_mm) - ? '1' : '0'; - buf[1] = '\n'; - - return simple_read_from_buffer(user_buf, count, ppos, buf, 2); -} - -static ssize_t tlblazy_write_file(struct file *file, - const char __user *user_buf, size_t count, loff_t *ppos) -{ - bool val; - - if (kstrtobool_from_user(user_buf, count, &val)) - return -EINVAL; - - if (val) - static_branch_enable(&__tlb_defer_switch_to_init_mm); - else - static_branch_disable(&__tlb_defer_switch_to_init_mm); - - return count; -} - -static const struct file_operations fops_tlblazy = { - .read = tlblazy_read_file, - .write = tlblazy_write_file, - .llseek = default_llseek, -}; - -static int __init init_tlblazy(void) -{ - if (boot_cpu_has(X86_FEATURE_PCID)) { - /* - * If we have PCID, then switching to init_mm is reasonably - * fast. If we don't have PCID, then switching to init_mm is - * quite slow, so we default to trying to defer it in the - * hopes that we can avoid it entirely. The latter approach - * runs the risk of receiving otherwise unnecessary IPIs. - * - * We can't do this in setup_pcid() because static keys - * haven't been initialized yet, and it would blow up - * badly. - */ - static_branch_disable(&__tlb_defer_switch_to_init_mm); - } - - debugfs_create_file("tlb_defer_switch_to_init_mm", S_IRUSR | S_IWUSR, - arch_debugfs_dir, NULL, &fops_tlblazy); - return 0; -} -late_initcall(init_tlblazy); |