| Message ID | 20200318230145.72097-1-gshan@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: Dereference CPU operations indirectly | expand |
On Thu, Mar 19, 2020 at 10:01:41AM +1100, Gavin Shan wrote: > Gavin Shan (4): > arm64: Declare ACPI parking protocol CPU operation if needed > arm64: Rename cpu_read_ops() to init_cpu_ops() > arm64: Introduce get_cpu_ops() helper function > arm64: Remove CPU operations dereferencing array I queued the first 3 patches for 5.7, they are useful on their own as a code clean-up. I'll wait for the debate with Mark to settle on the last patch. Thanks.
On 3/25/20 4:29 AM, Catalin Marinas wrote: > On Thu, Mar 19, 2020 at 10:01:41AM +1100, Gavin Shan wrote: >> Gavin Shan (4): >> arm64: Declare ACPI parking protocol CPU operation if needed >> arm64: Rename cpu_read_ops() to init_cpu_ops() >> arm64: Introduce get_cpu_ops() helper function >> arm64: Remove CPU operations dereferencing array > > I queued the first 3 patches for 5.7, they are useful on their own as a > code clean-up. I'll wait for the debate with Mark to settle on the last > patch. > > Thanks. > Thanks, Catalin. I'm also waiting for further comments on the last patch from Mark. The patch can also be dropped if your guys think it's not needed. Anyway, please let me know :) Thanks, Gavin
The subject perhaps can't precisely indicate what this series does, but keep it same as before for consistency. In current implementation, an array (@cpu_ops[NR_CPUS]) is maintained to dereference the CPU operations. 2KB memory are consumed when NR_CPUS is configured to 256. It's too much than what I expected. This series reworks the implementation to dereference the CPU operations by using two CPU operations pointer with assumption - all secondary CPUs should have unified CPU operations. With this, 16-bytes memory will be used for same purpose. PATCH[1/4] isn't too much relevant, to declare ACPI parking protocol only when CONFIG_ARM64_ACPI_PARKING_PROTOCOL has been enabled. PATCH[2/4] renames cpu_read_ops() to init_cpu_ops(), which is obviously more precise because it's initializing the CPU operations. PATCH[3/4] introduces get_cpu_ops(), preparing for droping the array of CPU operations. PATCH[4/4] removes the CPU operations deferencing array and replaces it with two pointers with the assumption: all secondary CPUs should have same enablement method. Changelog ========= v5: * Rebase to 5.6.rc6 and retest (Gavin Shan) * Improved commit log for PATCH[1] (Gavin Shan) * Add helper function __cpu_try_die() (Mark Rutland) * Two pointers to track the operations for boot CPU and the secondary CPUs separately (Mark Rutland) * Drop PATCH[5] because @cpu parameter is still needed by get_cpu_ops() (Gavin Shan) v4: * Rebase to 5.6.rc3 and retest (Gavin Shan) * Improved commit log for PATCH[4/5] with link tag (Lorenzo Pieralisi) * Using pointer instead of index to dereference the unified CPU operations (Lorenzo Pieralisi) * Merge logic of cpu_get_ops() to get_cpu_method() (Gavin Shan) v3: * Assume all CPUs have same enablement method. With this, the used memory is further squeezed from 64 bytes to 4 bytes (Lorenzo Pieralisi) * Add PATCH[5/5] to remove argument of get_cpu_ops() (Gavin Shan) v2: * Pack 4 CPUs' indexes into one byte. 64 bytes are consumed in order to get the CPU operations (Robin Murphy) * Use ARRAY_SIZE() to iterate @cpu_ops[] (Robin Murphy) * Make index-0 valid (Robin Murphy) Gavin Shan (4): arm64: Declare ACPI parking protocol CPU operation if needed arm64: Rename cpu_read_ops() to init_cpu_ops() arm64: Introduce get_cpu_ops() helper function arm64: Remove CPU operations dereferencing array arch/arm64/include/asm/cpu_ops.h | 8 +-- arch/arm64/kernel/cpu_ops.c | 84 +++++++++++++++++--------------- arch/arm64/kernel/cpuidle.c | 9 ++-- arch/arm64/kernel/setup.c | 8 +-- arch/arm64/kernel/smp.c | 72 +++++++++++++++++---------- 5 files changed, 107 insertions(+), 74 deletions(-)