diff options
Diffstat (limited to 'Documentation/robust-futex-ABI.txt')
| -rw-r--r-- | Documentation/robust-futex-ABI.txt | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/robust-futex-ABI.txt b/Documentation/robust-futex-ABI.txt index 16eb314f56cc..8a5d34abf726 100644 --- a/Documentation/robust-futex-ABI.txt +++ b/Documentation/robust-futex-ABI.txt @@ -1,7 +1,9 @@ -Started by Paul Jackson <pj@sgi.com> - +==================== The robust futex ABI --------------------- +==================== + +:Author: Started by Paul Jackson <pj@sgi.com> + Robust_futexes provide a mechanism that is used in addition to normal futexes, for kernel assist of cleanup of held locks on task exit. @@ -32,7 +34,7 @@ probably causing deadlock or other such failure of the other threads waiting on the same locks. A thread that anticipates possibly using robust_futexes should first -issue the system call: +issue the system call:: asmlinkage long sys_set_robust_list(struct robust_list_head __user *head, size_t len); @@ -91,7 +93,7 @@ that lock using the futex mechanism. When a thread has invoked the above system call to indicate it anticipates using robust_futexes, the kernel stores the passed in 'head' pointer for that task. The task may retrieve that value later on by -using the system call: +using the system call:: asmlinkage long sys_get_robust_list(int pid, struct robust_list_head __user **head_ptr, @@ -135,6 +137,7 @@ manipulating this list), the user code must observe the following protocol on 'lock entry' insertion and removal: On insertion: + 1) set the 'list_op_pending' word to the address of the 'lock entry' to be inserted, 2) acquire the futex lock, @@ -143,6 +146,7 @@ On insertion: 4) clear the 'list_op_pending' word. On removal: + 1) set the 'list_op_pending' word to the address of the 'lock entry' to be removed, 2) remove the lock entry for this lock from the 'head' list, |