Date: Fri, 1 May 2009 15:36:02 +0000 (UTC) From: Dmitry Chagin <dchagin@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/amd64/linux32 linux32_sysvec.c src/sys/compat/linux linux_futex.c src/sys/i386/linux linux_sysvec.c Message-ID: <200905011538.n41FcDgc069556@repoman.freebsd.org>
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dchagin 2009-05-01 15:36:02 UTC
FreeBSD src repository
Modified files:
sys/amd64/linux32 linux32_sysvec.c
sys/compat/linux linux_futex.c
sys/i386/linux linux_sysvec.c
Log:
SVN rev 191719 on 2009-05-01 15:36:02Z by dchagin
Reimplement futexes.
Old implemention used Giant to protect the kernel data structures,
but at the same time called malloc(M_WAITOK), that could cause the
calling thread to sleep and lost Giant protection. User-visible
result was the missed wakeup.
New implementation uses one sx lock per futex. The sx protects
the futex structures and allows to sleep while copyin or copyout
are performed.
Unlike linux, we return EINVAL when FUTEX_CMP_REQUEUE operation
is requested and either caller specified futexes are equial or
second futex already exists. This is acceptable since the situation
can only occur from the application error, and glibc falls back to
old FUTEX_WAKE operation when FUTEX_CMP_REQUEUE returns an error.
Approved by: kib (mentor)
MFC after: 1 month
Revision Changes Path
1.47 +3 -3 src/sys/amd64/linux32/linux32_sysvec.c
1.20 +450 -359 src/sys/compat/linux/linux_futex.c
1.163 +3 -3 src/sys/i386/linux/linux_sysvec.c
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