Commit ccb64941 authored Sep 11, 2017 by Boris Ostrovsky Committed by Thomas Gleixner Sep 25, 2017

x86/timers: Move simple_udelay_calibration() past kvmclock_init()



simple_udelay_calibration() relies on x86_platform's calibration ops.
For KVM these ops are set late in setup_arch() and so
simple_udelay_calibration() ends up using native version.

Besides being possibly incorrect, this significantly increases kernel
boot time. For example, on my laptop executing start_kernel() by a guest
takes ~10 times more than when KVM's ops are used.

Since early_xdbc_setup_hardware() relies on calibration having been
performed move it too.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: baolu.lu@linux.intel.com
Link: https://lkml.kernel.org/r/20170911185111.20636-1-boris.ostrovsky@oracle.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent af576850

arch/x86/kernel/setup.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -1029,8 +1029,6 @@ void __init setup_arch(char **cmdline_p)
		*/
		init_hypervisor_platform();

		tsc_early_delay_calibrate();

		x86_init.resources.probe_roms();

		/* after parse_early_param, so could debug it */
		@@ -1115,9 +1113,6 @@ void __init setup_arch(char **cmdline_p)
		memblock_set_current_limit(ISA_END_ADDRESS);
		e820__memblock_setup();

		if (!early_xdbc_setup_hardware())
		early_xdbc_register_console();

		reserve_bios_regions();

		if (efi_enabled(EFI_MEMMAP)) {
		@@ -1223,6 +1218,10 @@ void __init setup_arch(char **cmdline_p)
		kvmclock_init();
		#endif

		tsc_early_delay_calibrate();
		if (!early_xdbc_setup_hardware())
		early_xdbc_register_console();

		x86_init.paging.pagetable_init();

		kasan_init();