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| author |   Eric Biggers <ebiggers@google.com> | 2018-12-04 22:20:05 -0800 |
|---|---|---|
| committer |   Herbert Xu <herbert@gondor.apana.org.au> | 2018-12-13 18:24:58 +0800 |
| commit | a033aed5a84eb93a32929b6862602cb283d39e82 (patch) | |
| tree | 333b9c17544307a5f9fa06ffac438bd116f4f727 /arch/x86/crypto | |
| parent | crypto: x86/chacha - add XChaCha12 support (diff) | |
| download | linux-dev-a033aed5a84eb93a32929b6862602cb283d39e82.tar.xz linux-dev-a033aed5a84eb93a32929b6862602cb283d39e82.zip | |
crypto: x86/chacha - yield the FPU occasionally
To improve responsiveness, yield the FPU (temporarily re-enabling
preemption) every 4 KiB encrypted/decrypted, rather than keeping
preemption disabled during the entire encryption/decryption operation.
Alternatively we could do this for every skcipher_walk step, but steps
may be small in some cases, and yielding the FPU is expensive on x86.
Suggested-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/x86/crypto')
| -rw-r--r-- | arch/x86/crypto/chacha_glue.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/crypto/chacha_glue.c b/arch/x86/crypto/chacha_glue.c index d19c2908be90..9b1d3fac4943 100644 --- a/arch/x86/crypto/chacha_glue.c +++ b/arch/x86/crypto/chacha_glue.c @@ -132,6 +132,7 @@ static int chacha_simd_stream_xor(struct skcipher_request *req, { u32 *state, state_buf[16 + 2] __aligned(8); struct skcipher_walk walk; + int next_yield = 4096; /* bytes until next FPU yield */ int err; BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16); @@ -144,12 +145,21 @@ static int chacha_simd_stream_xor(struct skcipher_request *req, while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes; - if (nbytes < walk.total) + if (nbytes < walk.total) { nbytes = round_down(nbytes, walk.stride); + next_yield -= nbytes; + } chacha_dosimd(state, walk.dst.virt.addr, walk.src.virt.addr, nbytes, ctx->nrounds); + if (next_yield <= 0) { + /* temporarily allow preemption */ + kernel_fpu_end(); + kernel_fpu_begin(); + next_yield = 4096; + } + err = skcipher_walk_done(&walk, walk.nbytes - nbytes); } |