x86/smpboot: Remove APIC.wait_for_init_deassert and atomic init_deasserted
authorLen Brown <len.brown@intel.com>
Sun, 16 Aug 2015 15:45:48 +0000 (11:45 -0400)
committerIngo Molnar <mingo@kernel.org>
Mon, 17 Aug 2015 08:42:28 +0000 (10:42 +0200)
commit656bba306827a44ed73b3f93f75bb3147de17fae
tree649f20edd161667db4bf441847e34c5f8f38b6d9
parenta9bcaa02a5104ace6a9d9e4a9cd9192a9e7744d6
x86/smpboot: Remove APIC.wait_for_init_deassert and atomic init_deasserted

Both the per-APIC flag ".wait_for_init_deassert",
and the global atomic_t "init_deasserted"
are dead code -- remove them.

For all APIC types, "wait_for_master()"
prevents an AP from proceeding until the BSP has set
cpu_callout_mask, making "init_deasserted" {unnecessary}:

BSP: <de-assert INIT>
...
BSP: {set init_deasserted}
AP: wait_for_master()
set cpu_initialized_mask
wait for cpu_callout_mask
BSP: test cpu_initialized_mask
BSP: set cpu_callout_mask
AP: test cpu_callout_mask
AP: {wait for init_deasserted}
...
AP: <touch APIC>

Deleting the {dead code} above is necessary to enable
some parallelism in a future patch.

Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/de4b3a9bab894735e285870b5296da25ee6a8a5a.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/apic.h
arch/x86/kernel/apic/apic_flat_64.c
arch/x86/kernel/apic/apic_noop.c
arch/x86/kernel/apic/apic_numachip.c
arch/x86/kernel/apic/bigsmp_32.c
arch/x86/kernel/apic/probe_32.c
arch/x86/kernel/apic/x2apic_cluster.c
arch/x86/kernel/apic/x2apic_phys.c
arch/x86/kernel/apic/x2apic_uv_x.c
arch/x86/kernel/smpboot.c