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| author | Jens Axboe <jens.axboe@oracle.com> | 2008-01-24 08:54:47 +0100 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-01-28 10:50:36 +0100 |
| commit | fadad878cc0640cc9cd5569998bf54b693f7b38b (patch) | |
| tree | 9ad8c65d458d45f970f7e78cd1512c0e7da58def | |
| parent | 521f3bbdba6b92582ef8047df01b156668343542 (diff) | |
| download | lwn-fadad878cc0640cc9cd5569998bf54b693f7b38b.tar.gz lwn-fadad878cc0640cc9cd5569998bf54b693f7b38b.zip | |
kernel: add CLONE_IO to specifically request sharing of IO contexts
syslets (or other threads/processes that want io context sharing) can
set this to enforce sharing of io context.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 14 |
2 files changed, 11 insertions, 4 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 80837e7d527e..2d0546e884ea 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -27,6 +27,7 @@ #define CLONE_NEWUSER 0x10000000 /* New user namespace */ #define CLONE_NEWPID 0x20000000 /* New pid namespace */ #define CLONE_NEWNET 0x40000000 /* New network namespace */ +#define CLONE_IO 0x80000000 /* Clone io context */ /* * Scheduling policies diff --git a/kernel/fork.c b/kernel/fork.c index 1987c57abb08..314f5101d2b0 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -792,15 +792,21 @@ out: return error; } -static int copy_io(struct task_struct *tsk) +static int copy_io(unsigned long clone_flags, struct task_struct *tsk) { #ifdef CONFIG_BLOCK struct io_context *ioc = current->io_context; if (!ioc) return 0; - - if (ioprio_valid(ioc->ioprio)) { + /* + * Share io context with parent, if CLONE_IO is set + */ + if (clone_flags & CLONE_IO) { + tsk->io_context = ioc_task_link(ioc); + if (unlikely(!tsk->io_context)) + return -ENOMEM; + } else if (ioprio_valid(ioc->ioprio)) { tsk->io_context = alloc_io_context(GFP_KERNEL, -1); if (unlikely(!tsk->io_context)) return -ENOMEM; @@ -1176,7 +1182,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, goto bad_fork_cleanup_mm; if ((retval = copy_namespaces(clone_flags, p))) goto bad_fork_cleanup_keys; - if ((retval = copy_io(p))) + if ((retval = copy_io(clone_flags, p))) goto bad_fork_cleanup_namespaces; retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); if (retval) |