tree 8eba714127aa6876a78daae42440510743896363
parent 51dd6e01525bfb381e65fbaea86365846eb77c03
author Luis Chamberlain <mcgrof@kernel.org> 1679708280 -0700
committer Luis Chamberlain <mcgrof@kernel.org> 1680714233 -0700

modules/kmod: replace implementation with a sempahore

Simplfy the concurrency delimiter we user for kmod with the semaphore.
I had used the kmod strategy to try to implement a similar concurrency
delimiter for the kernel_read*() calls from the finit_module() path
so to reduce vmalloc() memory pressure. That effort didn't provid yet
conclusive results, but one thing that did became clear is we can use
the suggested alternative solution with semaphores which Linus hinted
at instead of using the atomic / wait strategy.

I've stress tested this with kmod test 0008:

time /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008

And I get only a *slight* delay. That delay however is small, a few
seconds for a full test loop run that runs 150 times, for about ~30-40
seconds. The small delay is worth the simplfication IMHO.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>