| Message ID | 20221219203733.3063192-2-elliott@hpe.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: yield at end of operations | expand |
On Mon, Dec 19, 2022 at 02:37:31PM -0600, Robert Elliott wrote: > > diff --git a/crypto/skcipher.c b/crypto/skcipher.c > index 0ecab31cfe79..cdead632117a 100644 > --- a/crypto/skcipher.c > +++ b/crypto/skcipher.c > @@ -153,13 +153,20 @@ int skcipher_walk_done(struct skcipher_walk *walk, int err) > scatterwalk_done(&walk->in, 0, nbytes); > scatterwalk_done(&walk->out, 1, nbytes); > > - if (nbytes) { > - crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? > - CRYPTO_TFM_REQ_MAY_SLEEP : 0); > + /* > + * Allow scheduler to use the CPU since it has been busy, > + * regardless of whether another loop pass is due > + */ > + crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? > + CRYPTO_TFM_REQ_MAY_SLEEP : 0); > + > + if (nbytes) > return skcipher_walk_next(walk); > - } > > finish: > + crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? > + CRYPTO_TFM_REQ_MAY_SLEEP : 0); > + You're calling crypto_yield twice if nbytes == 0. How about deleting the second crypto_yield call because the only case where it would matter is when n == 0. Thanks,
diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 0ecab31cfe79..cdead632117a 100644 --- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -153,13 +153,20 @@ int skcipher_walk_done(struct skcipher_walk *walk, int err) scatterwalk_done(&walk->in, 0, nbytes); scatterwalk_done(&walk->out, 1, nbytes); - if (nbytes) { - crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? - CRYPTO_TFM_REQ_MAY_SLEEP : 0); + /* + * Allow scheduler to use the CPU since it has been busy, + * regardless of whether another loop pass is due + */ + crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? + CRYPTO_TFM_REQ_MAY_SLEEP : 0); + + if (nbytes) return skcipher_walk_next(walk); - } finish: + crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? + CRYPTO_TFM_REQ_MAY_SLEEP : 0); + /* Short-circuit for the common/fast path. */ if (!((unsigned long)walk->buffer | (unsigned long)walk->page)) goto out;
Always yield to the scheduler at the end of skcipher_walk_done(), not just if additional bytes are left to be processed. This avoids soft lockups if drivers are invoked back-to-back to process data that is an integer multiple of their block size. Example: while processing 1 MiB buffers, multiple skciphers run from 192 s to 218 s without ever yielding to the scheduler, causing three soft lockup complaints. The kernel is configured for CONFIG_PREEMPT_NONE=y (or preempt=none on the kernel command line), so only explicit cond_resched() calls trigger scheduling - might_resched() and preempt_enable() do not (see kernel/sched/core.c). [ 190.865601] tcrypt: PERL my %speeds_skcipher = ( [ 192.041157] tcrypt: PERL "cbc-aes-aesni" => 2396490, [ 192.373934] tcrypt: PERL "ctr-aes-aesni" => 574888, [ 193.548967] tcrypt: PERL "cts-cbc-aes-aesni" => 2396018, [ 193.909077] tcrypt: PERL "ecb-aes-aesni" => 631824, [ 194.223801] tcrypt: PERL "xctr-aes-aesni" => 535778, [ 194.608548] tcrypt: PERL "xts-aes-aesni" => 676518, [ 196.440247] tcrypt: PERL "ctr-aria-avx" => 3804224, [ 196.675788] tcrypt: PERL "xchacha12-simd" => 368668, [ 196.988868] tcrypt: PERL "xchacha20-simd" => 535314, [ 197.301510] tcrypt: PERL "chacha20-simd" => 535142, [ 198.590113] tcrypt: PERL "ctr-sm4-aesni-avx2" => 2642930, [ 208.975253] tcrypt: PERL "cfb-sm4-aesni-avx2" => 22499840, [ 218.187217] watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [modprobe:3433] [ 246.181238] Modules linked in: tcrypt(+) hctr2 essiv adiantum ... [ 246.185048] RIP: 0010:measure_skcipher_bigbuf.constprop.0.isra.0+0x282/0x393 [tcrypt] [ 246.185304] Code: 00 0f 31 ... ... [ 218.197313] Call Trace: [ 218.197567] <TASK> [ 218.197822] ? 0xffffffffc052a000 [ 218.198079] do_test.cold+0x989/0xc7a [tcrypt] [ 218.198340] ? 0xffffffffc052a000 [ 218.198595] tcrypt_mod_init+0x50/0x1000 [tcrypt] [ 218.198857] ? 0xffffffffc052a000 [ 218.199112] do_one_initcall+0x41/0x200 ... [ 219.391776] tcrypt: PERL "cbc-sm4-aesni-avx2" => 22528138, [ 221.560847] tcrypt: PERL "ctr-sm4-aesni-avx" => 4560732, [ 231.960414] tcrypt: PERL "cfb-sm4-aesni-avx" => 22498380, [ 242.350070] tcrypt: PERL "cbc-sm4-aesni-avx" => 22527668, [ 244.471181] tcrypt: PERL "ecb-sm4-aesni-avx" => 4469626, ... [ 246.181064] watchdog: BUG: soft lockup - CPU#1 stuck for 52s! [modprobe:3433] ... [ 250.168239] tcrypt: PERL "cbc-camellia-aesni-avx2" => 12202738, [ 255.840094] tcrypt: PERL "cbc-camellia-aesni" => 12203096, [ 264.047440] tcrypt: PERL "cbc-cast5-avx" => 17744280, [ 273.091258] tcrypt: PERL "cbc-cast6-avx" => 19375400, [ 274.183249] watchdog: BUG: soft lockup - CPU#1 stuck for 78s! [modprobe:3433] ... [ 283.066260] tcrypt: PERL "cbc-serpent-avx2" => 21454930, [ 292.983848] tcrypt: PERL "cbc-serpent-avx" => 21452996, ... By adding a unilateral call to crypto_yield(), which calls cond_resched() and lets the scheduler use the CPU for another thread, that no longer happens. Starting at 2218 s, there is no soft lockup reported at 2244 s: [ 2217.202692] tcrypt: PERL my %speeds_skcipher = ( [ 2218.450215] tcrypt: PERL "cbc-aes-aesni" => 2179138, [ 2218.950960] tcrypt: PERL "cbc-aes-aesni" => 538738, [ 2219.460618] tcrypt: PERL "ctr-aes-aesni" => 575212, [ 2219.983006] tcrypt: PERL "ctr-aes-aesni" => 574402, [ 2221.329550] tcrypt: PERL "cts-cbc-aes-aesni" => 2182864, [ 2221.840599] tcrypt: PERL "cts-cbc-aes-aesni" => 539064, [ 2222.344290] tcrypt: PERL "ecb-aes-aesni" => 537402, [ 2222.869201] tcrypt: PERL "ecb-aes-aesni" => 537730, [ 2223.400315] tcrypt: PERL "xctr-aes-aesni" => 534824, [ 2223.897915] tcrypt: PERL "xctr-aes-aesni" => 534782, [ 2224.414956] tcrypt: PERL "xts-aes-aesni" => 539592, [ 2224.923715] tcrypt: PERL "xts-aes-aesni" => 539356, [ 2226.740211] tcrypt: PERL "ctr-aria-avx" => 3392444, [ 2228.545624] tcrypt: PERL "ctr-aria-avx" => 3392068, [ 2228.869883] tcrypt: PERL "xchacha12-simd" => 368932, [ 2229.204980] tcrypt: PERL "xchacha12-simd" => 374122, [ 2229.609975] tcrypt: PERL "xchacha20-simd" => 535596, [ 2230.022425] tcrypt: PERL "xchacha20-simd" => 537500, [ 2230.429674] tcrypt: PERL "chacha20-simd" => 535474, [ 2230.831041] tcrypt: PERL "chacha20-simd" => 534264, [ 2232.278150] tcrypt: PERL "ctr-sm4-aesni-avx2" => 2640770, [ 2233.744781] tcrypt: PERL "ctr-sm4-aesni-avx2" => 2642520, [ 2244.290542] tcrypt: PERL "cfb-sm4-aesni-avx2" => 22497308, [ 2245.725044] tcrypt: PERL "cfb-sm4-aesni-avx2" => 2604468, [ 2256.279228] tcrypt: PERL "cbc-sm4-aesni-avx2" => 22526084, [ 2257.729868] tcrypt: PERL "cbc-sm4-aesni-avx2" => 2600460, [ 2260.068782] tcrypt: PERL "ctr-sm4-aesni-avx" => 4560650, [ 2262.414663] tcrypt: PERL "ctr-sm4-aesni-avx" => 4561468, [ 2272.943000] tcrypt: PERL "cfb-sm4-aesni-avx" => 22496026, [ 2275.233755] tcrypt: PERL "cfb-sm4-aesni-avx" => 4456984, [ 2285.779516] tcrypt: PERL "cbc-sm4-aesni-avx" => 22525908, [ 2288.081160] tcrypt: PERL "cbc-sm4-aesni-avx" => 4457036, [ 2290.374086] tcrypt: PERL "ecb-sm4-aesni-avx" => 4465790, [ 2292.677381] tcrypt: PERL "ecb-sm4-aesni-avx" => 4466014, [ 2298.544718] tcrypt: PERL "cbc-camellia-aesni-avx2" => 12246268, [ 2299.869611] tcrypt: PERL "cbc-camellia-aesni-avx2" => 2349440, [ 2305.734078] tcrypt: PERL "cbc-camellia-aesni" => 12246930, [ 2307.746065] tcrypt: PERL "cbc-camellia-aesni" => 3832992, [ 2316.127414] tcrypt: PERL "cbc-cast5-avx" => 17737348, [ 2318.703437] tcrypt: PERL "cbc-cast5-avx" => 5061014, [ 2327.694881] tcrypt: PERL "cbc-cast6-avx" => 19065488, [ 2331.672188] tcrypt: PERL "cbc-cast6-avx" => 8145590, [ 2341.750274] tcrypt: PERL "cbc-serpent-avx2" => 21453172, [ 2343.209420] tcrypt: PERL "cbc-serpent-avx2" => 2611702, Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Signed-off-by: Robert Elliott <elliott@hpe.com> --- crypto/skcipher.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)