| Message ID | eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 902137ba8e469ed07c7f120a390161937a6288fb |
| Headers | show |
| Series | powerpc/vdso32 enhancement and optimisation | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (2e6c4d7e1c5990fa2ccca6db0868a05640ac1df1) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 44 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Mon, 2019-12-02 at 07:57:27 UTC, Christophe Leroy wrote: > Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added > getcpu() for PPC64 only, by making use of a user readable general > purpose SPR. > > PPC32 doesn't have any such SPR. > > For non SMP, just return CPU id 0 from the VDSO directly. > PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0. > > Before the patch, vdsotest reported: > getcpu: syscall: 1572 nsec/call > getcpu: libc: 1787 nsec/call > getcpu: vdso: not tested > > Now, vdsotest reports: > getcpu: syscall: 1582 nsec/call > getcpu: libc: 502 nsec/call > getcpu: vdso: 187 nsec/call > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Patches 1, 2 and 4-8, applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/902137ba8e469ed07c7f120a390161937a6288fb cheers
diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile index 06f54d947057..e147bbdc12cd 100644 --- a/arch/powerpc/kernel/vdso32/Makefile +++ b/arch/powerpc/kernel/vdso32/Makefile @@ -2,9 +2,7 @@ # List of files in the vdso, has to be asm only for now -obj-vdso32-$(CONFIG_PPC64) = getcpu.o -obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o \ - $(obj-vdso32-y) +obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o getcpu.o # Build rules diff --git a/arch/powerpc/kernel/vdso32/getcpu.S b/arch/powerpc/kernel/vdso32/getcpu.S index 63e914539e1a..90b39af14383 100644 --- a/arch/powerpc/kernel/vdso32/getcpu.S +++ b/arch/powerpc/kernel/vdso32/getcpu.S @@ -15,6 +15,7 @@ * int __kernel_getcpu(unsigned *cpu, unsigned *node); * */ +#if defined(CONFIG_PPC64) V_FUNCTION_BEGIN(__kernel_getcpu) .cfi_startproc mfspr r5,SPRN_SPRG_VDSO_READ @@ -31,3 +32,19 @@ V_FUNCTION_BEGIN(__kernel_getcpu) blr .cfi_endproc V_FUNCTION_END(__kernel_getcpu) +#elif !defined(CONFIG_SMP) +V_FUNCTION_BEGIN(__kernel_getcpu) + .cfi_startproc + cmpwi cr0, r3, 0 + cmpwi cr1, r4, 0 + li r5, 0 + beq cr0, 1f + stw r5, 0(r3) +1: li r3, 0 /* always success */ + crclr cr0*4+so + beqlr cr1 + stw r5, 0(r4) + blr + .cfi_endproc +V_FUNCTION_END(__kernel_getcpu) +#endif diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S index 00c025ba4a92..5206c2eb2a1d 100644 --- a/arch/powerpc/kernel/vdso32/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S @@ -155,7 +155,7 @@ VERSION __kernel_sync_dicache_p5; __kernel_sigtramp32; __kernel_sigtramp_rt32; -#ifdef CONFIG_PPC64 +#if defined(CONFIG_PPC64) || !defined(CONFIG_SMP) __kernel_getcpu; #endif
Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added getcpu() for PPC64 only, by making use of a user readable general purpose SPR. PPC32 doesn't have any such SPR. For non SMP, just return CPU id 0 from the VDSO directly. PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0. Before the patch, vdsotest reported: getcpu: syscall: 1572 nsec/call getcpu: libc: 1787 nsec/call getcpu: vdso: not tested Now, vdsotest reports: getcpu: syscall: 1582 nsec/call getcpu: libc: 502 nsec/call getcpu: vdso: 187 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v2: fixed build error in getcpu.S v3: dropped the fast system call, only support non SMP for now. --- arch/powerpc/kernel/vdso32/Makefile | 4 +--- arch/powerpc/kernel/vdso32/getcpu.S | 17 +++++++++++++++++ arch/powerpc/kernel/vdso32/vdso32.lds.S | 2 +- 3 files changed, 19 insertions(+), 4 deletions(-)