[PATCH] x86_64: Remove excessive stack allocation in MCE code with large NR_CPUS (f0de53bb) · Commits · 戴 / test

Remove excessive stack allocation in MCE code with large NR_CPUS Signed-off-by:

arch/x86_64/kernel/mce.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -379,18 +379,23 @@ static void collect_tscs(void *data)

		static ssize_t mce_read(struct file filp, char __user ubuf, size_t usize, loff_t *off)
		{
		unsigned long cpu_tsc[NR_CPUS];
		unsigned long *cpu_tsc;
		static DECLARE_MUTEX(mce_read_sem);
		unsigned next;
		char __user *buf = ubuf;
		int i, err;

		cpu_tsc = kmalloc(NR_CPUS * sizeof(long), GFP_KERNEL);
		if (!cpu_tsc)
		return -ENOMEM;

		down(&mce_read_sem);
		next = rcu_dereference(mcelog.next);

		/* Only supports full reads right now */
		if (off != 0 \|\| usize < MCE_LOG_LENsizeof(struct mce)) {
		up(&mce_read_sem);
		kfree(cpu_tsc);
		return -EINVAL;
		}

		@@ -421,6 +426,7 @@ static ssize_t mce_read(struct file filp, char __user ubuf, size_t usize, loff
		}
		}
		up(&mce_read_sem);
		kfree(cpu_tsc);
		return err ? -EFAULT : buf - ubuf;
		}