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crypto: api - optimize algorithm registration when self-tests disabled

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Currently, registering an algorithm with the crypto API always causes a
notification to be posted to the "cryptomgr", which then creates a
kthread to self-test the algorithm.  However, if self-tests are disabled
in the kconfig (as is the default option), then this kthread just
notifies waiters that the algorithm has been tested, then exits.

This causes a significant amount of overhead, especially in the kthread
creation and destruction, which is not necessary at all.  For example,
in a quick test I found that booting a "minimum" x86_64 kernel with all
the crypto options enabled (except for the self-tests) takes about 400ms
until PID 1 can start.  Of that, a full 13ms is spent just doing this
pointless dance, involving a kthread being created, run, and destroyed
over 200 times.  That's over 3% of the entire kernel start time.

Fix this by just skipping the creation of the test larval and the
posting of the registration notification entirely, when self-tests are
disabled.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
2022-11-13 16:12:33 -08:00
committed by Herbert Xu
parent 719c547c65
commit a7008584ab
2 changed files with 87 additions and 72 deletions
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3
crypto/api.c
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@@ -172,9 +172,6 @@ void crypto_wait_for_test(struct crypto_larval *larval)
err = wait_for_completion_killable(&larval->completion);
WARN_ON(err);
if (!err)
crypto_notify(CRYPTO_MSG_ALG_LOADED, larval);
out:
crypto_larval_kill(&larval->alg);
}