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authorJens Axboe <jens.axboe@oracle.com>2008-01-24 02:54:47 -0500
committerJens Axboe <jens.axboe@oracle.com>2008-01-28 04:50:36 -0500
commitfadad878cc0640cc9cd5569998bf54b693f7b38b (patch)
tree9ad8c65d458d45f970f7e78cd1512c0e7da58def
parent521f3bbdba6b92582ef8047df01b156668343542 (diff)
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.h1
-rw-r--r--kernel/fork.c14
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 @@
27#define CLONE_NEWUSER 0x10000000 /* New user namespace */ 27#define CLONE_NEWUSER 0x10000000 /* New user namespace */
28#define CLONE_NEWPID 0x20000000 /* New pid namespace */ 28#define CLONE_NEWPID 0x20000000 /* New pid namespace */
29#define CLONE_NEWNET 0x40000000 /* New network namespace */ 29#define CLONE_NEWNET 0x40000000 /* New network namespace */
30#define CLONE_IO 0x80000000 /* Clone io context */
30 31
31/* 32/*
32 * Scheduling policies 33 * 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:
792 return error; 792 return error;
793} 793}
794 794
795static int copy_io(struct task_struct *tsk) 795static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
796{ 796{
797#ifdef CONFIG_BLOCK 797#ifdef CONFIG_BLOCK
798 struct io_context *ioc = current->io_context; 798 struct io_context *ioc = current->io_context;
799 799
800 if (!ioc) 800 if (!ioc)
801 return 0; 801 return 0;
802 802 /*
803 if (ioprio_valid(ioc->ioprio)) { 803 * Share io context with parent, if CLONE_IO is set
804 */
805 if (clone_flags & CLONE_IO) {
806 tsk->io_context = ioc_task_link(ioc);
807 if (unlikely(!tsk->io_context))
808 return -ENOMEM;
809 } else if (ioprio_valid(ioc->ioprio)) {
804 tsk->io_context = alloc_io_context(GFP_KERNEL, -1); 810 tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
805 if (unlikely(!tsk->io_context)) 811 if (unlikely(!tsk->io_context))
806 return -ENOMEM; 812 return -ENOMEM;
@@ -1176,7 +1182,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
1176 goto bad_fork_cleanup_mm; 1182 goto bad_fork_cleanup_mm;
1177 if ((retval = copy_namespaces(clone_flags, p))) 1183 if ((retval = copy_namespaces(clone_flags, p)))
1178 goto bad_fork_cleanup_keys; 1184 goto bad_fork_cleanup_keys;
1179 if ((retval = copy_io(p))) 1185 if ((retval = copy_io(clone_flags, p)))
1180 goto bad_fork_cleanup_namespaces; 1186 goto bad_fork_cleanup_namespaces;
1181 retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); 1187 retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
1182 if (retval) 1188 if (retval)