| Message ID | 1538815744-27408-1-git-send-email-zhangshaokun@hisilicon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: mm: Drop the unused cpu parameter | expand |
On Sat, Oct 06, 2018 at 04:49:04PM +0800, Shaokun Zhang wrote: > Cpu parameter is never used in flush_context, remove it. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> > --- > arch/arm64/mm/context.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Acked-by: Will Deacon <will.deacon@arm.com> Curious, but does this actually result in better code generation, or does GCC already figure out that the parameter is unused? Will
Hi Will, On 2018/10/9 19:57, Will Deacon wrote: > On Sat, Oct 06, 2018 at 04:49:04PM +0800, Shaokun Zhang wrote: >> Cpu parameter is never used in flush_context, remove it. >> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> >> --- >> arch/arm64/mm/context.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) > > Acked-by: Will Deacon <will.deacon@arm.com> > > Curious, but does this actually result in better code generation, or does > GCC already figure out that the parameter is unused? > No hint from GCC compiler, the unused parameter is found when debug one context switch issue and analyze the code. It is redundant and harmless to remove it, a trivial patch. Thanks, Shaokun > Will > > . >
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index c127f94..009a7b2c 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -88,7 +88,7 @@ void verify_cpu_asid_bits(void) } } -static void flush_context(unsigned int cpu) +static void flush_context(void) { int i; u64 asid; @@ -142,7 +142,7 @@ static bool check_update_reserved_asid(u64 asid, u64 newasid) return hit; } -static u64 new_context(struct mm_struct *mm, unsigned int cpu) +static u64 new_context(struct mm_struct *mm) { static u32 cur_idx = 1; u64 asid = atomic64_read(&mm->context.id); @@ -180,7 +180,7 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu) /* We're out of ASIDs, so increment the global generation count */ generation = atomic64_add_return_relaxed(ASID_FIRST_VERSION, &asid_generation); - flush_context(cpu); + flush_context(); /* We have more ASIDs than CPUs, so this will always succeed */ asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, 1); @@ -223,7 +223,7 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu) /* Check that our ASID belongs to the current generation. */ asid = atomic64_read(&mm->context.id); if ((asid ^ atomic64_read(&asid_generation)) >> asid_bits) { - asid = new_context(mm, cpu); + asid = new_context(mm); atomic64_set(&mm->context.id, asid); }
Cpu parameter is never used in flush_context, remove it. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> --- arch/arm64/mm/context.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)