[v9,06/10] eal: add thread lifetime management
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Commit Message
From: Narcisa Vasile <navasile@microsoft.com>
Add function for thread creation, join, canceling, detaching.
The *rte_thread_create()* function can optionally receive an rte_thread_attr_t
object that will cause the thread to be created with the affinity and priority
described by the attributes object. If no rte_thread_attr_t is passed
(parameter is NULL), the default affinity and priority are used.
On Windows, the function executed by a thread when the thread starts is
represeneted by a function pointer of type DWORD (*func) (void*).
On other platforms, the function pointer is a void* (*func) (void*).
Performing a cast between these two types of function pointers to
uniformize the API on all platforms may result in undefined behavior.
TO fix this issue, a wrapper that respects the signature required by
CreateThread() has been created on Windows.
Signed-off-by: Narcisa Vasile <navasile@microsoft.com>
---
lib/eal/common/rte_thread.c | 116 +++++++++++++++++++++++++
lib/eal/include/rte_thread.h | 67 +++++++++++++++
lib/eal/windows/rte_thread.c | 162 +++++++++++++++++++++++++++++++++++
3 files changed, 345 insertions(+)
Comments
2021-06-04 16:44 (UTC-0700), Narcisa Ana Maria Vasile:
[...]
> diff --git a/lib/eal/include/rte_thread.h b/lib/eal/include/rte_thread.h
> index 5c54cd9d67..1d481b9ad5 100644
> --- a/lib/eal/include/rte_thread.h
> +++ b/lib/eal/include/rte_thread.h
> @@ -208,6 +208,73 @@ __rte_experimental
> int rte_thread_attr_set_priority(rte_thread_attr_t *thread_attr,
> enum rte_thread_priority priority);
>
> +/**
> + * Create a new thread that will invoke the 'thread_func' routine.
> + *
> + * @param thread_id
> + * A pointer that will store the id of the newly created thread.
> + *
> + * @param thread_attr
> + * Attributes that are used at the creation of the new thread.
> + *
> + * @param thread_func
> + * The routine that the new thread will invoke when starting execution.
> + *
> + * @param args
> + * Arguments to be passed to the 'thread_func' routine.
> + *
> + * @return
> + * On success, return 0.
> + * On failure, return a positive errno-style error number.
> + */
> +__rte_experimental
> +int rte_thread_create(rte_thread_t *thread_id,
> + const rte_thread_attr_t *thread_attr,
> + void *(*thread_func)(void *), void *args);
1. Thread function prototype is used at least in 4 places,
maybe give it a name, like `rte_thread_func`?
2. We can't easily support it's `void*` return type on Windows,
because it doesn't fit in DWORD. In `rte_thread_join` below you use `int`.
All `pthread_join` usages in DPDK ignore return value, but I'd rather keep it.
Do you think it's OK to stick to `int`?
[...]
> +/**
> + * Terminates a thread.
> + *
> + * @param thread_id
> + * The id of the thread to be cancelled.
> + *
> + * @return
> + * On success, return 0.
> + * On failure, return a positive errno-style error number.
> + */
> +__rte_experimental
> +int rte_thread_cancel(rte_thread_t thread_id);
What do you think of making this function internal for now?
We don't want applications to rely on this prototype.
To hide it from Doxygen, `/*` comment or #ifndef __DOXYGEN__ can be used.
It is worth noting in commit message
that it's not implemented for Windows and why.
> +
> +/**
> + * Detaches a thread.
Please explain what it means, because detaching is a pthread concept.
> + *
> + * @param thread_id
> + * The id of the thread to be cancelled.
Not "cancelled".
> + *
> + * @return
> + * On success, return 0.
> + * On failure, return a positive errno-style error number.
> + */
> +__rte_experimental
> +int rte_thread_detach(rte_thread_t thread_id);
> +
> +
Redundant empty line.
> #ifdef RTE_HAS_CPUSET
>
> /**
> diff --git a/lib/eal/windows/rte_thread.c b/lib/eal/windows/rte_thread.c
> index 6dc3d575c0..5afdd54e15 100644
> --- a/lib/eal/windows/rte_thread.c
> +++ b/lib/eal/windows/rte_thread.c
> @@ -14,6 +14,11 @@ struct eal_tls_key {
> DWORD thread_index;
> };
>
> +struct thread_routine_ctx {
> + void* (*start_routine) (void*);
> + void *routine_args;
> +};
> +
> /* Translates the most common error codes related to threads */
> static int
> thread_translate_win32_error(DWORD error)
> @@ -346,6 +351,163 @@ rte_thread_attr_set_priority(rte_thread_attr_t *thread_attr,
> return 0;
> }
>
> +static DWORD
> +thread_func_wrapper(void *args)
> +{
> + struct thread_routine_ctx *pctx = args;
> + intptr_t func_ret = 0;
> + struct thread_routine_ctx ctx = { NULL, NULL };
> +
> + ctx.start_routine = pctx->start_routine;
> + ctx.routine_args = pctx->routine_args;
> +
> + free(pctx);
> +
> + func_ret = (intptr_t)ctx.start_routine(ctx.routine_args);
> + return (DWORD)func_ret;
> +}
> +
> +int
> +rte_thread_create(rte_thread_t *thread_id,
> + const rte_thread_attr_t *thread_attr,
> + void *(*thread_func)(void *), void *args)
> +{
> + int ret = 0;
> + DWORD tid = 0;
> + HANDLE thread_handle = NULL;
> + GROUP_AFFINITY thread_affinity;
> + struct thread_routine_ctx *ctx = NULL;
> +
> + ctx = calloc(1, sizeof(*ctx));
Why use `calloc()` for a scalar?
[...]
> +int
> +rte_thread_cancel(rte_thread_t thread_id)
> +{
> + int ret = 0;
> + HANDLE thread_handle = NULL;
> +
> + thread_handle = OpenThread(THREAD_TERMINATE, FALSE, thread_id.opaque_id);
> + if (thread_handle == NULL) {
> + ret = thread_log_last_error("OpenThread()");
> + goto cleanup;
> + }
> +
> + /*
> + * TODO: Behavior is different between POSIX and Windows threads.
> + * POSIX threads wait for a cancellation point.
> + * Current Windows emulation kills thread at any point.
> + */
> + ret = TerminateThread(thread_handle, 0);
> + if (ret != 0) {
> + ret = thread_log_last_error("TerminateThread()");
> + goto cleanup;
> + }
> +
> +cleanup:
> + if (thread_handle != NULL) {
> + CloseHandle(thread_handle);
> + thread_handle = NULL;
> + }
> + return ret;
> +}
As we've discussed before, such implementation should never be used.
I suggest removing it for now, otherwise if someone enables the code
calling rte_thread_cancel() for Windows, it will almost certainly lead
to deadlock bugs.
> +
> +int
> +rte_thread_detach(rte_thread_t thread_id)
> +{
> + (void)thread_id;
RTE_SET_USED/__rte_unused
> + return ENOTSUP;
> +}
> +
It should return success as the thread is in detached state after the call.
> int
> rte_thread_key_create(rte_thread_key *key,
> __rte_unused void (*destructor)(void *))
On Wed, Jun 09, 2021 at 02:04:09AM +0300, Dmitry Kozlyuk wrote:
> 2021-06-04 16:44 (UTC-0700), Narcisa Ana Maria Vasile:
> [...]
> > diff --git a/lib/eal/include/rte_thread.h b/lib/eal/include/rte_thread.h
> > index 5c54cd9d67..1d481b9ad5 100644
> > --- a/lib/eal/include/rte_thread.h
> > +++ b/lib/eal/include/rte_thread.h
> > +__rte_experimental
> > +int rte_thread_create(rte_thread_t *thread_id,
> > + const rte_thread_attr_t *thread_attr,
> > + void *(*thread_func)(void *), void *args);
>
> 1. Thread function prototype is used at least in 4 places,
> maybe give it a name, like `rte_thread_func`?
>
> 2. We can't easily support it's `void*` return type on Windows,
> because it doesn't fit in DWORD. In `rte_thread_join` below you use `int`.
> All `pthread_join` usages in DPDK ignore return value, but I'd rather keep it.
> Do you think it's OK to stick to `int`?
>
Thank you, I agree that we should keep it. I've changed it to unsigned long
to fit with Windows's DWORD as well.
> [...]
> > +/**
> > + * Terminates a thread.
> > + *
> > + * @param thread_id
> > + * The id of the thread to be cancelled.
> > + *
> > + * @return
> > + * On success, return 0.
> > + * On failure, return a positive errno-style error number.
> > + */
> > +__rte_experimental
> > +int rte_thread_cancel(rte_thread_t thread_id);
>
> What do you think of making this function internal for now?
> We don't want applications to rely on this prototype.
> To hide it from Doxygen, `/*` comment or #ifndef __DOXYGEN__ can be used.
> It is worth noting in commit message
> that it's not implemented for Windows and why.
>
Thank you, I've removed it for now.
> > +
> > + HANDLE thread_handle = NULL;
> > + GROUP_AFFINITY thread_affinity;
> > + struct thread_routine_ctx *ctx = NULL;
> > +
> > + ctx = calloc(1, sizeof(*ctx));
>
> Why use `calloc()` for a scalar?
ctx is pointer to struct that holds the thread function pointer and its arguments.
Did I misunderstand what you meant?
>
2021-06-18 14:41 (UTC-0700), Narcisa Ana Maria Vasile:
> On Wed, Jun 09, 2021 at 02:04:09AM +0300, Dmitry Kozlyuk wrote:
> > 2021-06-04 16:44 (UTC-0700), Narcisa Ana Maria Vasile:
[...]
> > > +
> > > + HANDLE thread_handle = NULL;
> > > + GROUP_AFFINITY thread_affinity;
> > > + struct thread_routine_ctx *ctx = NULL;
> > > +
> > > + ctx = calloc(1, sizeof(*ctx));
> >
> > Why use `calloc()` for a scalar?
>
> ctx is pointer to struct that holds the thread function pointer and its arguments.
> Did I misunderstand what you meant?
`calloc(size_t n, size_t size)` mainly exists for safe array allocations,
because multiplication in `malloc(n * size)` may overflow. You are allocating
a singular value, i. e. a scalar, so the choice of `calloc()` over `malloc()`
raises questions. Nevertheless, it is harmless and works correctly. Consider
it a nit.
@@ -149,6 +149,122 @@ rte_thread_attr_set_priority(rte_thread_attr_t *thread_attr,
return 0;
}
+int
+rte_thread_create(rte_thread_t *thread_id,
+ const rte_thread_attr_t *thread_attr,
+ void *(*thread_func)(void *), void *args)
+{
+ int ret = 0;
+ pthread_attr_t attr;
+ pthread_attr_t *attrp = NULL;
+ struct sched_param param = {
+ .sched_priority = 0,
+ };
+ int policy = SCHED_OTHER;
+
+ if (thread_attr != NULL) {
+ ret = pthread_attr_init(&attr);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_attr_init failed\n");
+ goto cleanup;
+ }
+
+ attrp = &attr;
+
+ /*
+ * Set the inherit scheduler parameter to explicit,
+ * otherwise the priority attribute is ignored.
+ */
+ ret = pthread_attr_setinheritsched(attrp,
+ PTHREAD_EXPLICIT_SCHED);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_attr_setinheritsched failed\n");
+ goto cleanup;
+ }
+
+ /*
+ * In case a realtime scheduling policy is requested,
+ * the sched_priority parameter is set to the value stored in
+ * thread_attr. Otherwise, for the default scheduling policy
+ * (SCHED_OTHER) sched_priority needs to be initialized to 0.
+ */
+ if (thread_attr->priority == RTE_THREAD_PRIORITY_REALTIME_CRITICAL) {
+ policy = SCHED_RR;
+ param.sched_priority = thread_attr->priority;
+ }
+
+ ret = pthread_attr_setschedpolicy(attrp, policy);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_attr_setschedpolicy failed\n");
+ goto cleanup;
+ }
+
+ ret = pthread_attr_setschedparam(attrp, ¶m);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_attr_setschedparam failed\n");
+ goto cleanup;
+ }
+
+ ret = pthread_attr_setaffinity_np(attrp,
+ sizeof(thread_attr->cpuset),
+ &thread_attr->cpuset);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_attr_setaffinity_np failed\n");
+ goto cleanup;
+ }
+ }
+
+ ret = pthread_create(&thread_id->opaque_id, attrp, thread_func, args);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_create failed\n");
+ goto cleanup;
+ }
+
+cleanup:
+ if (attrp != NULL)
+ pthread_attr_destroy(&attr);
+
+ return ret;
+}
+
+int
+rte_thread_join(rte_thread_t thread_id, int *value_ptr)
+{
+ int ret = 0;
+ void *res = NULL;
+ void **pres = NULL;
+
+ if (value_ptr != NULL)
+ pres = &res;
+
+ ret = pthread_join(thread_id.opaque_id, pres);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "pthread_join failed\n");
+ return ret;
+ }
+
+ if (pres != NULL)
+ *value_ptr = *(int *)(*pres);
+
+ return 0;
+}
+
+int rte_thread_cancel(rte_thread_t thread_id)
+{
+ /*
+ * TODO: Behavior is different between POSIX and Windows threads.
+ * POSIX threads wait for a cancellation point.
+ * Current Windows emulation kills thread at any point.
+ */
+ return pthread_cancel(thread_id.opaque_id);
+}
+
+int
+rte_thread_detach(rte_thread_t thread_id)
+{
+ return pthread_detach(thread_id.opaque_id);
+}
+
int
rte_thread_key_create(rte_thread_key *key, void (*destructor)(void *))
{
@@ -208,6 +208,73 @@ __rte_experimental
int rte_thread_attr_set_priority(rte_thread_attr_t *thread_attr,
enum rte_thread_priority priority);
+/**
+ * Create a new thread that will invoke the 'thread_func' routine.
+ *
+ * @param thread_id
+ * A pointer that will store the id of the newly created thread.
+ *
+ * @param thread_attr
+ * Attributes that are used at the creation of the new thread.
+ *
+ * @param thread_func
+ * The routine that the new thread will invoke when starting execution.
+ *
+ * @param args
+ * Arguments to be passed to the 'thread_func' routine.
+ *
+ * @return
+ * On success, return 0.
+ * On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_create(rte_thread_t *thread_id,
+ const rte_thread_attr_t *thread_attr,
+ void *(*thread_func)(void *), void *args);
+
+/**
+ * Waits for the thread identified by 'thread_id' to terminate
+ *
+ * @param thread_id
+ * The identifier of the thread.
+ *
+ * @param value_ptr
+ * Stores the exit status of the thread.
+ *
+ * @return
+ * On success, return 0.
+ * On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_join(rte_thread_t thread_id, int *value_ptr);
+
+/**
+ * Terminates a thread.
+ *
+ * @param thread_id
+ * The id of the thread to be cancelled.
+ *
+ * @return
+ * On success, return 0.
+ * On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_cancel(rte_thread_t thread_id);
+
+/**
+ * Detaches a thread.
+ *
+ * @param thread_id
+ * The id of the thread to be cancelled.
+ *
+ * @return
+ * On success, return 0.
+ * On failure, return a positive errno-style error number.
+ */
+__rte_experimental
+int rte_thread_detach(rte_thread_t thread_id);
+
+
#ifdef RTE_HAS_CPUSET
/**
@@ -14,6 +14,11 @@ struct eal_tls_key {
DWORD thread_index;
};
+struct thread_routine_ctx {
+ void* (*start_routine) (void*);
+ void *routine_args;
+};
+
/* Translates the most common error codes related to threads */
static int
thread_translate_win32_error(DWORD error)
@@ -346,6 +351,163 @@ rte_thread_attr_set_priority(rte_thread_attr_t *thread_attr,
return 0;
}
+static DWORD
+thread_func_wrapper(void *args)
+{
+ struct thread_routine_ctx *pctx = args;
+ intptr_t func_ret = 0;
+ struct thread_routine_ctx ctx = { NULL, NULL };
+
+ ctx.start_routine = pctx->start_routine;
+ ctx.routine_args = pctx->routine_args;
+
+ free(pctx);
+
+ func_ret = (intptr_t)ctx.start_routine(ctx.routine_args);
+ return (DWORD)func_ret;
+}
+
+int
+rte_thread_create(rte_thread_t *thread_id,
+ const rte_thread_attr_t *thread_attr,
+ void *(*thread_func)(void *), void *args)
+{
+ int ret = 0;
+ DWORD tid = 0;
+ HANDLE thread_handle = NULL;
+ GROUP_AFFINITY thread_affinity;
+ struct thread_routine_ctx *ctx = NULL;
+
+ ctx = calloc(1, sizeof(*ctx));
+ if (ctx == NULL) {
+ RTE_LOG(DEBUG, EAL, "Insufficient memory for thread context allocations\n");
+ ret = ENOMEM;
+ goto cleanup;
+ }
+ ctx->routine_args = args;
+ ctx->start_routine = thread_func;
+
+ thread_handle = CreateThread(NULL, 0, thread_func_wrapper, ctx,
+ CREATE_SUSPENDED, &tid);
+ if (thread_handle == NULL) {
+ ret = thread_log_last_error("CreateThread()");
+ goto cleanup;
+ }
+ thread_id->opaque_id = tid;
+
+ if (thread_attr != NULL) {
+ if (CPU_COUNT(&thread_attr->cpuset) > 0) {
+ ret = rte_convert_cpuset_to_affinity(&thread_attr->cpuset, &thread_affinity);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "Unable to convert cpuset to thread affinity\n");
+ goto cleanup;
+ }
+
+ if (!SetThreadGroupAffinity(thread_handle, &thread_affinity, NULL)) {
+ ret = thread_log_last_error("SetThreadGroupAffinity()");
+ goto cleanup;
+ }
+ }
+ ret = rte_thread_set_priority(*thread_id, thread_attr->priority);
+ if (ret != 0) {
+ RTE_LOG(DEBUG, EAL, "Unable to set thread priority\n");
+ goto cleanup;
+ }
+ }
+
+ if (ResumeThread(thread_handle) == (DWORD)-1) {
+ ret = thread_log_last_error("ResumeThread()");
+ goto cleanup;
+ }
+
+ return 0;
+
+cleanup:
+ if (thread_handle != NULL) {
+ CloseHandle(thread_handle);
+ thread_handle = NULL;
+ }
+ return ret;
+}
+
+int
+rte_thread_join(rte_thread_t thread_id, int *value_ptr)
+{
+ HANDLE thread_handle = NULL;
+ DWORD result = 0;
+ DWORD exit_code = 0;
+ BOOL err = 0;
+ int ret = 0;
+
+ thread_handle = OpenThread(SYNCHRONIZE | THREAD_QUERY_INFORMATION,
+ FALSE, thread_id.opaque_id);
+ if (thread_handle == NULL) {
+ ret = thread_log_last_error("OpenThread()");
+ goto cleanup;
+ }
+
+ result = WaitForSingleObject(thread_handle, INFINITE);
+ if (result != WAIT_OBJECT_0) {
+ ret = thread_log_last_error("WaitForSingleObject()");
+ goto cleanup;
+ }
+
+ if (value_ptr != NULL) {
+ err = GetExitCodeThread(thread_handle, &exit_code);
+ if (err == 0) {
+ ret = thread_log_last_error("GetExitCodeThread()");
+ goto cleanup;
+ }
+ *value_ptr = exit_code;
+ }
+
+cleanup:
+ if (thread_handle != NULL) {
+ CloseHandle(thread_handle);
+ thread_handle = NULL;
+ }
+
+ return ret;
+}
+
+int
+rte_thread_cancel(rte_thread_t thread_id)
+{
+ int ret = 0;
+ HANDLE thread_handle = NULL;
+
+ thread_handle = OpenThread(THREAD_TERMINATE, FALSE, thread_id.opaque_id);
+ if (thread_handle == NULL) {
+ ret = thread_log_last_error("OpenThread()");
+ goto cleanup;
+ }
+
+ /*
+ * TODO: Behavior is different between POSIX and Windows threads.
+ * POSIX threads wait for a cancellation point.
+ * Current Windows emulation kills thread at any point.
+ */
+ ret = TerminateThread(thread_handle, 0);
+ if (ret != 0) {
+ ret = thread_log_last_error("TerminateThread()");
+ goto cleanup;
+ }
+
+cleanup:
+ if (thread_handle != NULL) {
+ CloseHandle(thread_handle);
+ thread_handle = NULL;
+ }
+ return ret;
+}
+
+int
+rte_thread_detach(rte_thread_t thread_id)
+{
+ (void)thread_id;
+ return ENOTSUP;
+}
+
int
rte_thread_key_create(rte_thread_key *key,
__rte_unused void (*destructor)(void *))