Lennart Poettering
fbe8f6928e
While stracing PID1's forking off of children I noticed that every single forked off child reads cap_last_cap from procfs. That value is a kernel constant, hence we can save a lot of work if we'd cache it. Thing is, we actually do cache it, in a thread_local cache field. This means that the forked off processes (which are considered new threads) will have to re-query it, even though we already know the result. Hence, let's get rid of the thread_local stuff (given that the value is going to be the same for all threads anyway, and we pretty much have a single thread only anyway). Use an C11 atomic_int instead, which ensures the value is either initialized or not initialized, but we don't need to be concerned of partial initialization. This makes the cap_last_cap reading go away in the children, as strace shows (since cap_last_cap() is already called by PID 1 before fork()ing, anyway).
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