Re: [PATCH 0/4] futex: get_user_pages_fast() for shared futexes

Ulrich Drepper
2008-10-01T03:13:54Z

On Tue, Sep 30, 2008 at 3:55 AM, Eric Dumazet <dada1@cosmosbay.com> wrote:
> I am not sure how it could be converted to private futexes, since
> old binaries (static glibc) will use FUTEX_WAKE like calls.

We considered this back when but any effort seems too much. We'd
either need a clone flag (a scarce resource) or replace the set_tid
_address syscall. Given that the futex is woken once per thread
lifetime it shouldn't be an issue. If the semaphore shows up even
after this patch feel free to introduce a new set_tid_address syscall.