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Commit 26799a63110dcbe81291ea53178f6b4810d07424

Authored by Ravikiran G Thirumalai
Committed by Ingo Molnar
1 parent b58602a4ba
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

x86: fix incorrect __read_mostly on _boot_cpu_pda 

The pda rework (commit 3461b0af025251bbc6b3d56c821c6ac2de6f7209)
to remove static boot cpu pdas introduced a performance bug.

_boot_cpu_pda is the actual pda used by the boot cpu and is definitely
not "__read_mostly" and ended up polluting the read mostly section with
writes.  This bug caused regression of about 8-10% on certain syscall
intensive workloads.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Acked-by: Mike Travis <travis@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff

arch/x86/kernel/head64.c
Diff comments   View file @ 26799a6
... ... @@ -27,7 +27,7 @@
27 27 #include <asm/trampoline.h>
28 28  
29 29 /* boot cpu pda */
30   -static struct x8664_pda _boot_cpu_pda __read_mostly;
  30 +static struct x8664_pda _boot_cpu_pda;
31 31  
32 32 #ifdef CONFIG_SMP
33 33 /*