On Wed, Nov 09, 2022 at 06:37:38PM -0800, Eric Biggers wrote: > From: Eric Biggers <ebiggers@xxxxxxxxxx> > > 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. Also compile out the unnecessary code in algboss.c. > > While this patch is an optimization and not a "fix" per se, I've marked > it as for stable, due to the large improvement it can make to boot time. > > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Unfortunately, this patch won't work because it breaks templates. There should still be a solution that at least avoids having to spawn kthreads, though... - Eric
