Fix SMP related bugs
* sched/sched: Fix a deadlock in SMP mode
Two months ago, I introduced sched_tasklist_lock() and
sched_tasklist_unlock() to protect tasklists in SMP mode.
Actually, this change works pretty well for HTTP audio
streaming aging test with lc823450-xgevk.
However, I found a deadlock in the scheduler when I tried
similar aging tests with DVFS autonomous mode where CPU
clock speed changed based on cpu load. In this case, call
sequences were as follows;
cpu1: sched_unlock()->sched_mergepending()->sched_addreadytorun()->up_cpu_pause()
cpu0: sched_lock()->sched_mergepending()
To avoid this deadlock, I added sched_tasklist_unlock() when calling
up_cpu_pause() and sched_addreadytorun(). Also, added
sched_tasklist_lock() after the call.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* libc: Add critical section in lib_filesem.c for SMP
To set my_pid into fs_folder atomically in SMP mode,
critical section API must be used.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* mm: Add critical section in mm_sem.c for SMP
To set my_pid into mm_folder atomically in SMP mode,
critical section API must be used.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
* net: Add critical section in net_lock.c for SMP
To set my pid (me) into fs_folder atomically in SMP mode,
critical section API must be used.
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>
binfmt/, configs/, grahics/, libc/, mm/, net/, sched/: OS references to the errno variable should always use the set_errno(), get_errno() macros
arch/arm/src/stm32 and stm32f7: Architecture-specific code is not permitted to modify the errno variable. drivers/ and libc/: OS references to the errno variable should always use the set_errno(), get_errno() macros
Replace all usage kill() in the OS proper with nxsig_kill().
sched/signal: Add nxsig_kill() which is functionally equivalent to kill() except that it does not modify the errno variable.
This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
sched/semaphore: Add nxsem_post() which is identical to sem_post() except that it never modifies the errno variable. Changed all references to sem_post in the OS to nxsem_post().
sched/semaphore: Add nxsem_destroy() which is identical to sem_destroy() except that it never modifies the errno variable. Changed all references to sem_destroy() in the OS to nxsem_destroy().
libc/semaphore and sched/semaphore: Add nxsem_getprotocol() and nxsem_setprotocola which are identical to sem_getprotocol() and set_setprotocol() except that they never modifies the errno variable. Changed all references to sem_setprotocol in the OS to nxsem_setprotocol(). sem_getprotocol() was not used in the OS
libc/semaphore: Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable. Changed all references to sem_getvalue in the OS to nxsem_getvalue().
sched/semaphore: Rename all internal private functions from sem_xyz to nxsem_xyz. The sem_ prefix is (will be) reserved only for the application semaphore interfaces.
libc/semaphore: Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable. Changed all references to sem_init in the OS to nxsem_init().
sched/semaphore: Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.
sched/semaphoate: Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
