On 11/12/2020 21:00, Peter Zijlstra wrote: > On Fri, Dec 11, 2020 at 07:29:04PM +0800, Tony W Wang-oc wrote: >> The driver crc32c-intel match CPUs supporting X86_FEATURE_XMM4_2. >> On platforms with Zhaoxin CPUs supporting this X86 feature, When >> crc32c-intel and crc32c-generic are both registered, system will >> use crc32c-intel because its .cra_priority is greater than >> crc32c-generic. This case expect to use crc32c-generic driver for >> some Zhaoxin CPUs to get performance gain, So remove these Zhaoxin >> CPUs support from crc32c-intel. >> >> Signed-off-by: Tony W Wang-oc <TonyWWang-oc@xxxxxxxxxxx> >> --- >> arch/x86/crypto/crc32c-intel_glue.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c >> index feccb52..6dafdae 100644 >> --- a/arch/x86/crypto/crc32c-intel_glue.c >> +++ b/arch/x86/crypto/crc32c-intel_glue.c >> @@ -222,8 +222,16 @@ MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id); >> >> static int __init crc32c_intel_mod_init(void) >> { >> + struct cpuinfo_x86 *c = &boot_cpu_data; >> + >> if (!x86_match_cpu(crc32c_cpu_id)) >> return -ENODEV; >> + >> + if (c->x86_vendor == X86_VENDOR_ZHAOXIN || c->x86_vendor == X86_VENDOR_CENTAUR) { >> + if (c->x86 == 0x6 || (c->x86 == 0x7 && c->x86_model <= 0x3b)) >> + return -ENODEV; >> + } > > Egads, why can't you use that x86_match_cpu() above, and also this > really wants a comment on why you're excluding these chips. When doing lmbench3 Create and Delete file test on partitions with ext4 enabling metadata checksum, found using crc32c-generic driver could get about 20% performance gain than using the driver crc32c-intel on these chips. Also, since > (IIRC) ZHAOXIN is basically AND, shouldn't they also be listed? > > That is; write it like: > > m = x86_match_cpu(crc32_cpu_id); > if (!m || !m->data) > return -ENODEV; > > That way you can have positive and negative matches in the array > (obviously the existing FEATURE test would need data=1 and be last). > . > Lot thanks for you suggestion, will list these chips in crc32c_cpu_id and use x86_match_cpu: static const struct x86_cpu_id crc32c_cpu_id[] = { + X86_MATCH_VENDOR_FAM_FEATURE(ZHAOXIN, 0x6, X86_FEATURE_XMM4_2, 1), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x1b, X86_FEATURE_XMM4_2, 1), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(ZHAOXIN, 0x7, 0x3b, X86_FEATURE_XMM4_2, 1), + X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 0x6, X86_FEATURE_XMM4_2, 1), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x1b, X86_FEATURE_XMM4_2, 1), + X86_MATCH_VENDOR_FAM_MODEL_FEATURE(CENTAUR, 0x7, 0x3b, X86_FEATURE_XMM4_2, 1), X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, NULL), {} }; @@ -228,8 +234,10 @@ MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id); static int __init crc32c_intel_mod_init(void) { - if (!x86_match_cpu(crc32c_cpu_id)) + const struct x86_cpu_id *m = x86_match_cpu(crc32c_cpu_id); + if (!m || m->driver_data) return -ENODEV; sincerely TonyWWangoc