x86/mm: Remove the UP asm/tlbflush.h code, always use the (formerly) SMP code
The UP asm/tlbflush.h generates somewhat nicer code than the SMP version.
Aside from that, it's fallen quite a bit behind the SMP code:
- flush_tlb_mm_range() didn't flush individual pages if the range
was small.
- The lazy TLB code was much weaker. This usually wouldn't matter,
but, if a kernel thread flushed its lazy "active_mm" more than
once (due to reclaim or similar), it wouldn't be unlazied and
would instead pointlessly flush repeatedly.
- Tracepoints were missing.
Aside from that, simply having the UP code around was a maintanence
burden, since it means that any change to the TLB flush code had to
make sure not to break it.
Simplify everything by deleting the UP code.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index c03b4a0..da1416c 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -15,7 +15,7 @@
#include <linux/debugfs.h>
/*
- * Smarter SMP flushing macros.
+ * TLB flushing, formerly SMP-only
* c/o Linus Torvalds.
*
* These mean you can really definitely utterly forget about
@@ -28,8 +28,6 @@
* Implement flush IPI by CALL_FUNCTION_VECTOR, Alex Shi
*/
-#ifdef CONFIG_SMP
-
/*
* We cannot call mmdrop() because we are in interrupt context,
* instead update mm->cpu_vm_mask.
@@ -53,8 +51,6 @@ void leave_mm(int cpu)
}
EXPORT_SYMBOL_GPL(leave_mm);
-#endif /* CONFIG_SMP */
-
void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
@@ -85,10 +81,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
set_pgd(pgd, init_mm.pgd[stack_pgd_index]);
}
-#ifdef CONFIG_SMP
this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
this_cpu_write(cpu_tlbstate.active_mm, next);
-#endif
cpumask_set_cpu(cpu, mm_cpumask(next));
@@ -146,9 +140,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
if (unlikely(prev->context.ldt != next->context.ldt))
load_mm_ldt(next);
#endif
- }
-#ifdef CONFIG_SMP
- else {
+ } else {
this_cpu_write(cpu_tlbstate.state, TLBSTATE_OK);
BUG_ON(this_cpu_read(cpu_tlbstate.active_mm) != next);
@@ -175,11 +167,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
load_mm_ldt(next);
}
}
-#endif
}
-#ifdef CONFIG_SMP
-
/*
* The flush IPI assumes that a thread switch happens in this order:
* [cpu0: the cpu that switches]
@@ -436,5 +425,3 @@ static int __init create_tlb_single_page_flush_ceiling(void)
return 0;
}
late_initcall(create_tlb_single_page_flush_ceiling);
-
-#endif /* CONFIG_SMP */