diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-23 15:57:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-24 07:21:01 -0700 |
| commit | ba0a6c9f6fceed11c6a99e8326f0477fe383e6b5 (patch) | |
| tree | 5c9967735f19b7b3332de90cae2cdd6c4457d30c /arch/alpha | |
| parent | 06f1631a1671bce2d59d58cb1debdf23e1803ebf (diff) | |
fcntl: add F_[SG]ETOWN_EX
In order to direct the SIGIO signal to a particular thread of a
multi-threaded application we cannot, like suggested by the manpage, put a
TID into the regular fcntl(F_SETOWN) call. It will still be send to the
whole process of which that thread is part.
Since people do want to properly direct SIGIO we introduce F_SETOWN_EX.
The need to direct SIGIO comes from self-monitoring profiling such as with
perf-counters. Perf-counters uses SIGIO to notify that new sample data is
available. If the signal is delivered to the same task that generated the
new sample it can augment that data by inspecting the task's user-space
state right after it returns from the kernel. This is esp. convenient
for interpreted or virtual machine driven environments.
Both F_SETOWN_EX and F_GETOWN_EX take a pointer to a struct f_owner_ex
as argument:
struct f_owner_ex {
int type;
pid_t pid;
};
Where type is one of F_OWNER_TID, F_OWNER_PID or F_OWNER_GID.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: stephane eranian <eranian@googlemail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha')
| -rw-r--r-- | arch/alpha/include/asm/fcntl.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/fcntl.h b/arch/alpha/include/asm/fcntl.h index 25da0017ec8..e42823e954a 100644 --- a/arch/alpha/include/asm/fcntl.h +++ b/arch/alpha/include/asm/fcntl.h @@ -26,6 +26,8 @@ #define F_GETOWN 6 /* for sockets. */ #define F_SETSIG 10 /* for sockets. */ #define F_GETSIG 11 /* for sockets. */ +#define F_SETOWN_EX 12 +#define F_GETOWN_EX 13 /* for posix fcntl() and lockf() */ #define F_RDLCK 1 |