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authorAlex Shi <alex.shi@intel.com>2012-06-28 03:02:20 +0200
committerH. Peter Anvin <hpa@zytor.com>2012-06-28 04:29:10 +0200
commit3df3212f9722c7e45c723b9ea231a04ba4dbc47c (patch)
treecb93a81efb12b91813ed69e86bc5be24ca31de9d /arch/x86/mm
parentx86/tlb: add tlb_flushall_shift for specific CPU (diff)
downloadlinux-3df3212f9722c7e45c723b9ea231a04ba4dbc47c.tar.xz
linux-3df3212f9722c7e45c723b9ea231a04ba4dbc47c.zip
x86/tlb: add tlb_flushall_shift knob into debugfs
kernel will replace cr3 rewrite with invlpg when tlb_flush_entries <= active_tlb_entries / 2^tlb_flushall_factor if tlb_flushall_factor is -1, kernel won't do this replacement. User can modify its value according to specific CPU/applications. Thanks for Borislav providing the help message of CONFIG_DEBUG_TLBFLUSH. Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/r/1340845344-27557-6-git-send-email-alex.shi@intel.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/tlb.c51
1 files changed, 51 insertions, 0 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 2939f2f9edbb..5911f61e300e 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -12,6 +12,7 @@
#include <asm/cache.h>
#include <asm/apic.h>
#include <asm/uv/uv.h>
+#include <linux/debugfs.h>
DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate)
= { &init_mm, 0, };
@@ -430,3 +431,53 @@ void flush_tlb_all(void)
{
on_each_cpu(do_flush_tlb_all, NULL, 1);
}
+
+#ifdef CONFIG_DEBUG_TLBFLUSH
+static ssize_t tlbflush_read_file(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char buf[32];
+ unsigned int len;
+
+ len = sprintf(buf, "%hd\n", tlb_flushall_shift);
+ return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t tlbflush_write_file(struct file *file,
+ const char __user *user_buf, size_t count, loff_t *ppos)
+{
+ char buf[32];
+ ssize_t len;
+ s8 shift;
+
+ len = min(count, sizeof(buf) - 1);
+ if (copy_from_user(buf, user_buf, len))
+ return -EFAULT;
+
+ buf[len] = '\0';
+ if (kstrtos8(buf, 0, &shift))
+ return -EINVAL;
+
+ if (shift > 64)
+ return -EINVAL;
+
+ tlb_flushall_shift = shift;
+ return count;
+}
+
+static const struct file_operations fops_tlbflush = {
+ .read = tlbflush_read_file,
+ .write = tlbflush_write_file,
+ .llseek = default_llseek,
+};
+
+static int __cpuinit create_tlb_flushall_shift(void)
+{
+ if (cpu_has_invlpg) {
+ debugfs_create_file("tlb_flushall_shift", S_IRUSR | S_IWUSR,
+ arch_debugfs_dir, NULL, &fops_tlbflush);
+ }
+ return 0;
+}
+late_initcall(create_tlb_flushall_shift);
+#endif