From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- arch/alpha/lib/udelay.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 arch/alpha/lib/udelay.c (limited to 'arch/alpha/lib/udelay.c') diff --git a/arch/alpha/lib/udelay.c b/arch/alpha/lib/udelay.c new file mode 100644 index 000000000..873648263 --- /dev/null +++ b/arch/alpha/lib/udelay.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 1993, 2000 Linus Torvalds + * + * Delay routines, using a pre-computed "loops_per_jiffy" value. + */ + +#include +#include /* for udelay's use of smp_processor_id */ +#include +#include +#include + +/* + * Use only for very small delays (< 1 msec). + * + * The active part of our cycle counter is only 32-bits wide, and + * we're treating the difference between two marks as signed. On + * a 1GHz box, that's about 2 seconds. + */ + +void +__delay(int loops) +{ + int tmp; + __asm__ __volatile__( + " rpcc %0\n" + " addl %1,%0,%1\n" + "1: rpcc %0\n" + " subl %1,%0,%0\n" + " bgt %0,1b" + : "=&r" (tmp), "=r" (loops) : "1"(loops)); +} +EXPORT_SYMBOL(__delay); + +#ifdef CONFIG_SMP +#define LPJ cpu_data[smp_processor_id()].loops_per_jiffy +#else +#define LPJ loops_per_jiffy +#endif + +void +udelay(unsigned long usecs) +{ + usecs *= (((unsigned long)HZ << 32) / 1000000) * LPJ; + __delay((long)usecs >> 32); +} +EXPORT_SYMBOL(udelay); + +void +ndelay(unsigned long nsecs) +{ + nsecs *= (((unsigned long)HZ << 32) / 1000000000) * LPJ; + __delay((long)nsecs >> 32); +} +EXPORT_SYMBOL(ndelay); -- cgit v1.3.1