tree 0d2fe45705d946a917908c04f6a23cef106dee70
parent 74944287e1ab95e091107c9f26ce46bd50e13043
author Adam Langley <agl@google.com> 1536181792 -0700
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1546020318 +0000

Use thread-local storage for PRNG states if fork-unsafe buffering is enabled.

We switched from thread-local storage to a mutex-pool in 82639e6f53
because, for highly-threaded processes, the memory used by all the
states could be quite large. I had judged that a mutex-pool should be
fine, but had underestimated the PRNG requirements of some of our jobs.

This change makes rand.c support using either thread-locals or a
mutex-pool. Thread-locals are used if fork-unsafe buffering is enabled.
While not strictly related to fork-safety, we already have the
fork-unsafe control, and it's already set by jobs that care a lot about
PRNG performance, so fits quite nicely here.

Change-Id: Iaf1e0171c70d4c8dbe1e42283ea13df5b613cb2d
Reviewed-on: https://boringssl-review.googlesource.com/c/31564
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>