From: Jason A. Donenfeld > Sent: 13 October 2022 01:42 ... > > diff --git a/arch/x86/crypto/sha1_ssse3_glue.c b/arch/x86/crypto/sha1_ssse3_glue.c > > index 44340a1139e0..a9f5779b41ca 100644 > > --- a/arch/x86/crypto/sha1_ssse3_glue.c > > +++ b/arch/x86/crypto/sha1_ssse3_glue.c > > @@ -26,6 +26,8 @@ > > #include <crypto/sha1_base.h> > > #include <asm/simd.h> > > > > +#define FPU_BYTES 4096U /* avoid kernel_fpu_begin/end scheduler/rcu stalls */ > > Declare this inside the function it's used as an untyped enum, and give > it a better name, like BYTES_PER_FPU. Isn't 'bytes' the wrong unit anyway? At least it ought to be 'clocks' so it can be divided by the (approximate) 'clocks per byte' of the algorithm. Something like a crc is likely to be far faster than AES. Clearly the actual required units are microseconds. But depending on the actual cpu frequency is a bit hard. And people running faster cpu may want lower latency anyway. So a typical slow cpu frequency is probably ok. The actual architecture dependant constant really ought to be defined with kernel_fpu_begin(). David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
