#include <linux/smp.h>
#include <linux/file.h>
#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/hash.h>
#include <linux/sysfs.h>
#include <linux/dcache.h>
#include <linux/percpu.h>
void __weak hw_perf_disable(void) { barrier(); }
void __weak hw_perf_enable(void) { barrier(); }
-int __weak
-hw_perf_group_sched_in(struct perf_event *group_leader,
- struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- return 0;
-}
-
void __weak perf_event_print_debug(void) { }
static DEFINE_PER_CPU(int, perf_disable_count);
event->total_time_running = run_end - event->tstamp_running;
}
+/*
+ * Update total_time_enabled and total_time_running for all events in a group.
+ */
+static void update_group_times(struct perf_event *leader)
+{
+ struct perf_event *event;
+
+ update_event_times(leader);
+ list_for_each_entry(event, &leader->sibling_list, group_entry)
+ update_event_times(event);
+}
+
static struct list_head *
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
{
static void
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
{
- struct perf_event *group_leader = event->group_leader;
+ WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
+ event->attach_state |= PERF_ATTACH_CONTEXT;
/*
- * Depending on whether it is a standalone or sibling event,
- * add it straight to the context's event list, or to the group
- * leader's sibling list:
+ * If we're a stand alone event or group leader, we go to the context
+ * list, group events are kept attached to the group so that
+ * perf_group_detach can, at all times, locate all siblings.
*/
- if (group_leader == event) {
+ if (event->group_leader == event) {
struct list_head *list;
if (is_software_event(event))
list = ctx_group_list(event, ctx);
list_add_tail(&event->group_entry, list);
- } else {
- if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
- !is_software_event(event))
- group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
-
- list_add_tail(&event->group_entry, &group_leader->sibling_list);
- group_leader->nr_siblings++;
}
list_add_rcu(&event->event_entry, &ctx->event_list);
ctx->nr_stat++;
}
+static void perf_group_attach(struct perf_event *event)
+{
+ struct perf_event *group_leader = event->group_leader;
+
+ WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
+ event->attach_state |= PERF_ATTACH_GROUP;
+
+ if (group_leader == event)
+ return;
+
+ if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
+ !is_software_event(event))
+ group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
+
+ list_add_tail(&event->group_entry, &group_leader->sibling_list);
+ group_leader->nr_siblings++;
+}
+
/*
* Remove a event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
- struct perf_event *sibling, *tmp;
-
- if (list_empty(&event->group_entry))
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_CONTEXT))
return;
+
+ event->attach_state &= ~PERF_ATTACH_CONTEXT;
+
ctx->nr_events--;
if (event->attr.inherit_stat)
ctx->nr_stat--;
- list_del_init(&event->group_entry);
list_del_rcu(&event->event_entry);
- if (event->group_leader != event)
- event->group_leader->nr_siblings--;
+ if (event->group_leader == event)
+ list_del_init(&event->group_entry);
- update_event_times(event);
+ update_group_times(event);
/*
* If event was in error state, then keep it
*/
if (event->state > PERF_EVENT_STATE_OFF)
event->state = PERF_EVENT_STATE_OFF;
+}
+
+static void perf_group_detach(struct perf_event *event)
+{
+ struct perf_event *sibling, *tmp;
+ struct list_head *list = NULL;
+
+ /*
+ * We can have double detach due to exit/hot-unplug + close.
+ */
+ if (!(event->attach_state & PERF_ATTACH_GROUP))
+ return;
+
+ event->attach_state &= ~PERF_ATTACH_GROUP;
+
+ /*
+ * If this is a sibling, remove it from its group.
+ */
+ if (event->group_leader != event) {
+ list_del_init(&event->group_entry);
+ event->group_leader->nr_siblings--;
+ return;
+ }
+
+ if (!list_empty(&event->group_entry))
+ list = &event->group_entry;
/*
* If this was a group event with sibling events then
* upgrade the siblings to singleton events by adding them
- * to the context list directly:
+ * to whatever list we are on.
*/
list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
- struct list_head *list;
-
- list = ctx_group_list(event, ctx);
- list_move_tail(&sibling->group_entry, list);
+ if (list)
+ list_move_tail(&sibling->group_entry, list);
sibling->group_leader = sibling;
/* Inherit group flags from the previous leader */
}
/*
- * Update total_time_enabled and total_time_running for all events in a group.
- */
-static void update_group_times(struct perf_event *leader)
-{
- struct perf_event *event;
-
- update_event_times(leader);
- list_for_each_entry(event, &leader->sibling_list, group_entry)
- update_event_times(event);
-}
-
-/*
* Cross CPU call to disable a performance event
*/
static void __perf_event_disable(void *info)
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
- struct perf_event *event, *partial_group;
+ struct perf_event *event, *partial_group = NULL;
+ const struct pmu *pmu = group_event->pmu;
+ bool txn = false;
int ret;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
- ret = hw_perf_group_sched_in(group_event, cpuctx, ctx);
- if (ret)
- return ret < 0 ? ret : 0;
+ /* Check if group transaction availabe */
+ if (pmu->start_txn)
+ txn = true;
+
+ if (txn)
+ pmu->start_txn(pmu);
- if (event_sched_in(group_event, cpuctx, ctx))
+ if (event_sched_in(group_event, cpuctx, ctx)) {
+ if (txn)
+ pmu->cancel_txn(pmu);
return -EAGAIN;
+ }
/*
* Schedule in siblings as one group (if any):
}
}
- return 0;
+ if (!txn)
+ return 0;
+
+ ret = pmu->commit_txn(pmu);
+ if (!ret) {
+ pmu->cancel_txn(pmu);
+ return 0;
+ }
group_error:
/*
}
event_sched_out(group_event, cpuctx, ctx);
+ if (txn)
+ pmu->cancel_txn(pmu);
+
return -EAGAIN;
}
struct perf_event_context *ctx)
{
list_add_event(event, ctx);
+ perf_group_attach(event);
event->tstamp_enabled = ctx->time;
event->tstamp_running = ctx->time;
event->tstamp_stopped = ctx->time;
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_event_context *next_ctx;
struct perf_event_context *parent;
- struct pt_regs *regs;
int do_switch = 1;
- regs = task_pt_regs(task);
- perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
+ perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
if (likely(!ctx || !cpuctx->task_ctx))
return;
if (cpuctx->task_ctx == ctx)
return;
+ perf_disable();
+
/*
* We want to keep the following priority order:
* cpu pinned (that don't need to move), task pinned,
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
cpuctx->task_ctx = ctx;
+
+ perf_enable();
}
#define MAX_INTERRUPTS (~0ULL)
}
static void perf_pending_sync(struct perf_event *event);
+static void perf_mmap_data_put(struct perf_mmap_data *data);
static void free_event(struct perf_event *event)
{
atomic_dec(&nr_task_events);
}
- if (event->output) {
- fput(event->output->filp);
- event->output = NULL;
+ if (event->data) {
+ perf_mmap_data_put(event->data);
+ event->data = NULL;
}
if (event->destroy)
{
struct perf_event_context *ctx = event->ctx;
+ /*
+ * Remove from the PMU, can't get re-enabled since we got
+ * here because the last ref went.
+ */
+ perf_event_disable(event);
+
WARN_ON_ONCE(ctx->parent_ctx);
- mutex_lock(&ctx->mutex);
- perf_event_remove_from_context(event);
+ /*
+ * There are two ways this annotation is useful:
+ *
+ * 1) there is a lock recursion from perf_event_exit_task
+ * see the comment there.
+ *
+ * 2) there is a lock-inversion with mmap_sem through
+ * perf_event_read_group(), which takes faults while
+ * holding ctx->mutex, however this is called after
+ * the last filedesc died, so there is no possibility
+ * to trigger the AB-BA case.
+ */
+ mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
+ raw_spin_lock_irq(&ctx->lock);
+ perf_group_detach(event);
+ list_del_event(event, ctx);
+ raw_spin_unlock_irq(&ctx->lock);
mutex_unlock(&ctx->mutex);
mutex_lock(&event->owner->perf_event_mutex);
return ret;
}
-static int perf_event_set_output(struct perf_event *event, int output_fd);
+static const struct file_operations perf_fops;
+
+static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+{
+ struct file *file;
+
+ file = fget_light(fd, fput_needed);
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if (file->f_op != &perf_fops) {
+ fput_light(file, *fput_needed);
+ *fput_needed = 0;
+ return ERR_PTR(-EBADF);
+ }
+
+ return file->private_data;
+}
+
+static int perf_event_set_output(struct perf_event *event,
+ struct perf_event *output_event);
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return perf_event_period(event, (u64 __user *)arg);
case PERF_EVENT_IOC_SET_OUTPUT:
- return perf_event_set_output(event, arg);
+ {
+ struct perf_event *output_event = NULL;
+ int fput_needed = 0;
+ int ret;
+
+ if (arg != -1) {
+ output_event = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_event))
+ return PTR_ERR(output_event);
+ }
+
+ ret = perf_event_set_output(event, output_event);
+ if (output_event)
+ fput_light(output_event->filp, fput_needed);
+
+ return ret;
+ }
case PERF_EVENT_IOC_SET_FILTER:
return perf_event_set_filter(event, (void __user *)arg);
rcu_read_unlock();
}
-static unsigned long perf_data_size(struct perf_mmap_data *data)
-{
- return data->nr_pages << (PAGE_SHIFT + data->data_order);
-}
-
#ifndef CONFIG_PERF_USE_VMALLOC
/*
return virt_to_page(data->data_pages[pgoff - 1]);
}
+static void *perf_mmap_alloc_page(int cpu)
+{
+ struct page *page;
+ int node;
+
+ node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+ page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+ if (!page)
+ return NULL;
+
+ return page_address(page);
+}
+
static struct perf_mmap_data *
perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
{
unsigned long size;
int i;
- WARN_ON(atomic_read(&event->mmap_count));
-
size = sizeof(struct perf_mmap_data);
size += nr_pages * sizeof(void *);
if (!data)
goto fail;
- data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
+ data->user_page = perf_mmap_alloc_page(event->cpu);
if (!data->user_page)
goto fail_user_page;
for (i = 0; i < nr_pages; i++) {
- data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
+ data->data_pages[i] = perf_mmap_alloc_page(event->cpu);
if (!data->data_pages[i])
goto fail_data_pages;
}
- data->data_order = 0;
data->nr_pages = nr_pages;
return data;
kfree(data);
}
+static inline int page_order(struct perf_mmap_data *data)
+{
+ return 0;
+}
+
#else
/*
* Required for architectures that have d-cache aliasing issues.
*/
+static inline int page_order(struct perf_mmap_data *data)
+{
+ return data->page_order;
+}
+
static struct page *
perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
{
- if (pgoff > (1UL << data->data_order))
+ if (pgoff > (1UL << page_order(data)))
return NULL;
return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
int i, nr;
data = container_of(work, struct perf_mmap_data, work);
- nr = 1 << data->data_order;
+ nr = 1 << page_order(data);
base = data->user_page;
for (i = 0; i < nr + 1; i++)
unsigned long size;
void *all_buf;
- WARN_ON(atomic_read(&event->mmap_count));
-
size = sizeof(struct perf_mmap_data);
size += sizeof(void *);
data->user_page = all_buf;
data->data_pages[0] = all_buf + PAGE_SIZE;
- data->data_order = ilog2(nr_pages);
+ data->page_order = ilog2(nr_pages);
data->nr_pages = 1;
return data;
#endif
+static unsigned long perf_data_size(struct perf_mmap_data *data)
+{
+ return data->nr_pages << (PAGE_SHIFT + page_order(data));
+}
+
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct perf_event *event = vma->vm_file->private_data;
{
long max_size = perf_data_size(data);
- atomic_set(&data->lock, -1);
-
if (event->attr.watermark) {
data->watermark = min_t(long, max_size,
event->attr.wakeup_watermark);
if (!data->watermark)
data->watermark = max_size / 2;
-
+ atomic_set(&data->refcount, 1);
rcu_assign_pointer(event->data, data);
}
perf_mmap_data_free(data);
}
-static void perf_mmap_data_release(struct perf_event *event)
+static struct perf_mmap_data *perf_mmap_data_get(struct perf_event *event)
{
- struct perf_mmap_data *data = event->data;
+ struct perf_mmap_data *data;
- WARN_ON(atomic_read(&event->mmap_count));
+ rcu_read_lock();
+ data = rcu_dereference(event->data);
+ if (data) {
+ if (!atomic_inc_not_zero(&data->refcount))
+ data = NULL;
+ }
+ rcu_read_unlock();
+
+ return data;
+}
+
+static void perf_mmap_data_put(struct perf_mmap_data *data)
+{
+ if (!atomic_dec_and_test(&data->refcount))
+ return;
- rcu_assign_pointer(event->data, NULL);
call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
}
{
struct perf_event *event = vma->vm_file->private_data;
- WARN_ON_ONCE(event->ctx->parent_ctx);
if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
unsigned long size = perf_data_size(event->data);
- struct user_struct *user = current_user();
+ struct user_struct *user = event->mmap_user;
+ struct perf_mmap_data *data = event->data;
atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
- vma->vm_mm->locked_vm -= event->data->nr_locked;
- perf_mmap_data_release(event);
+ vma->vm_mm->locked_vm -= event->mmap_locked;
+ rcu_assign_pointer(event->data, NULL);
mutex_unlock(&event->mmap_mutex);
+
+ perf_mmap_data_put(data);
+ free_uid(user);
}
}
long user_extra, extra;
int ret = 0;
+ /*
+ * Don't allow mmap() of inherited per-task counters. This would
+ * create a performance issue due to all children writing to the
+ * same buffer.
+ */
+ if (event->cpu == -1 && event->attr.inherit)
+ return -EINVAL;
+
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
WARN_ON_ONCE(event->ctx->parent_ctx);
mutex_lock(&event->mmap_mutex);
- if (event->output) {
- ret = -EINVAL;
- goto unlock;
- }
-
- if (atomic_inc_not_zero(&event->mmap_count)) {
- if (nr_pages != event->data->nr_pages)
+ if (event->data) {
+ if (event->data->nr_pages == nr_pages)
+ atomic_inc(&event->data->refcount);
+ else
ret = -EINVAL;
goto unlock;
}
WARN_ON(event->data);
data = perf_mmap_data_alloc(event, nr_pages);
- ret = -ENOMEM;
- if (!data)
+ if (!data) {
+ ret = -ENOMEM;
goto unlock;
+ }
- ret = 0;
perf_mmap_data_init(event, data);
-
- atomic_set(&event->mmap_count, 1);
- atomic_long_add(user_extra, &user->locked_vm);
- vma->vm_mm->locked_vm += extra;
- event->data->nr_locked = extra;
if (vma->vm_flags & VM_WRITE)
event->data->writable = 1;
+ atomic_long_add(user_extra, &user->locked_vm);
+ event->mmap_locked = extra;
+ event->mmap_user = get_current_user();
+ vma->vm_mm->locked_vm += event->mmap_locked;
+
unlock:
+ if (!ret)
+ atomic_inc(&event->mmap_count);
mutex_unlock(&event->mmap_mutex);
vma->vm_flags |= VM_RESERVED;
}
static const struct file_operations perf_fops = {
+ .llseek = no_llseek,
.release = perf_release,
.read = perf_read,
.poll = perf_poll,
{
}
+
+/*
+ * We assume there is only KVM supporting the callbacks.
+ * Later on, we might change it to a list if there is
+ * another virtualization implementation supporting the callbacks.
+ */
+struct perf_guest_info_callbacks *perf_guest_cbs;
+
+int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = cbs;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
+
+int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+ perf_guest_cbs = NULL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+
/*
* Output
*/
}
/*
- * Curious locking construct.
- *
* We need to ensure a later event_id doesn't publish a head when a former
- * event_id isn't done writing. However since we need to deal with NMIs we
+ * event isn't done writing. However since we need to deal with NMIs we
* cannot fully serialize things.
*
- * What we do is serialize between CPUs so we only have to deal with NMI
- * nesting on a single CPU.
- *
* We only publish the head (and generate a wakeup) when the outer-most
- * event_id completes.
+ * event completes.
*/
-static void perf_output_lock(struct perf_output_handle *handle)
+static void perf_output_get_handle(struct perf_output_handle *handle)
{
struct perf_mmap_data *data = handle->data;
- int cur, cpu = get_cpu();
-
- handle->locked = 0;
- for (;;) {
- cur = atomic_cmpxchg(&data->lock, -1, cpu);
- if (cur == -1) {
- handle->locked = 1;
- break;
- }
- if (cur == cpu)
- break;
-
- cpu_relax();
- }
+ preempt_disable();
+ local_inc(&data->nest);
+ handle->wakeup = local_read(&data->wakeup);
}
-static void perf_output_unlock(struct perf_output_handle *handle)
+static void perf_output_put_handle(struct perf_output_handle *handle)
{
struct perf_mmap_data *data = handle->data;
unsigned long head;
- int cpu;
-
- data->done_head = data->head;
-
- if (!handle->locked)
- goto out;
again:
- /*
- * The xchg implies a full barrier that ensures all writes are done
- * before we publish the new head, matched by a rmb() in userspace when
- * reading this position.
- */
- while ((head = atomic_long_xchg(&data->done_head, 0)))
- data->user_page->data_head = head;
+ head = local_read(&data->head);
/*
- * NMI can happen here, which means we can miss a done_head update.
+ * IRQ/NMI can happen here, which means we can miss a head update.
*/
- cpu = atomic_xchg(&data->lock, -1);
- WARN_ON_ONCE(cpu != smp_processor_id());
+ if (!local_dec_and_test(&data->nest))
+ goto out;
/*
- * Therefore we have to validate we did not indeed do so.
+ * Publish the known good head. Rely on the full barrier implied
+ * by atomic_dec_and_test() order the data->head read and this
+ * write.
*/
- if (unlikely(atomic_long_read(&data->done_head))) {
- /*
- * Since we had it locked, we can lock it again.
- */
- while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
- cpu_relax();
+ data->user_page->data_head = head;
+ /*
+ * Now check if we missed an update, rely on the (compiler)
+ * barrier in atomic_dec_and_test() to re-read data->head.
+ */
+ if (unlikely(head != local_read(&data->head))) {
+ local_inc(&data->nest);
goto again;
}
- if (atomic_xchg(&data->wakeup, 0))
+ if (handle->wakeup != local_read(&data->wakeup))
perf_output_wakeup(handle);
-out:
- put_cpu();
+
+ out:
+ preempt_enable();
}
-void perf_output_copy(struct perf_output_handle *handle,
+__always_inline void perf_output_copy(struct perf_output_handle *handle,
const void *buf, unsigned int len)
{
- unsigned int pages_mask;
- unsigned long offset;
- unsigned int size;
- void **pages;
-
- offset = handle->offset;
- pages_mask = handle->data->nr_pages - 1;
- pages = handle->data->data_pages;
-
do {
- unsigned long page_offset;
- unsigned long page_size;
- int nr;
+ unsigned long size = min_t(unsigned long, handle->size, len);
- nr = (offset >> PAGE_SHIFT) & pages_mask;
- page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
- page_offset = offset & (page_size - 1);
- size = min_t(unsigned int, page_size - page_offset, len);
+ memcpy(handle->addr, buf, size);
- memcpy(pages[nr] + page_offset, buf, size);
+ len -= size;
+ handle->addr += size;
+ buf += size;
+ handle->size -= size;
+ if (!handle->size) {
+ struct perf_mmap_data *data = handle->data;
- len -= size;
- buf += size;
- offset += size;
+ handle->page++;
+ handle->page &= data->nr_pages - 1;
+ handle->addr = data->data_pages[handle->page];
+ handle->size = PAGE_SIZE << page_order(data);
+ }
} while (len);
-
- handle->offset = offset;
-
- /*
- * Check we didn't copy past our reservation window, taking the
- * possible unsigned int wrap into account.
- */
- WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
}
int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size,
int nmi, int sample)
{
- struct perf_event *output_event;
struct perf_mmap_data *data;
unsigned long tail, offset, head;
int have_lost;
if (event->parent)
event = event->parent;
- output_event = rcu_dereference(event->output);
- if (output_event)
- event = output_event;
-
data = rcu_dereference(event->data);
if (!data)
goto out;
handle->sample = sample;
if (!data->nr_pages)
- goto fail;
+ goto out;
- have_lost = atomic_read(&data->lost);
+ have_lost = local_read(&data->lost);
if (have_lost)
size += sizeof(lost_event);
- perf_output_lock(handle);
+ perf_output_get_handle(handle);
do {
/*
*/
tail = ACCESS_ONCE(data->user_page->data_tail);
smp_rmb();
- offset = head = atomic_long_read(&data->head);
+ offset = head = local_read(&data->head);
head += size;
if (unlikely(!perf_output_space(data, tail, offset, head)))
goto fail;
- } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
+ } while (local_cmpxchg(&data->head, offset, head) != offset);
- handle->offset = offset;
- handle->head = head;
+ if (head - local_read(&data->wakeup) > data->watermark)
+ local_add(data->watermark, &data->wakeup);
- if (head - tail > data->watermark)
- atomic_set(&data->wakeup, 1);
+ handle->page = offset >> (PAGE_SHIFT + page_order(data));
+ handle->page &= data->nr_pages - 1;
+ handle->size = offset & ((PAGE_SIZE << page_order(data)) - 1);
+ handle->addr = data->data_pages[handle->page];
+ handle->addr += handle->size;
+ handle->size = (PAGE_SIZE << page_order(data)) - handle->size;
if (have_lost) {
lost_event.header.type = PERF_RECORD_LOST;
lost_event.header.misc = 0;
lost_event.header.size = sizeof(lost_event);
lost_event.id = event->id;
- lost_event.lost = atomic_xchg(&data->lost, 0);
+ lost_event.lost = local_xchg(&data->lost, 0);
perf_output_put(handle, lost_event);
}
return 0;
fail:
- atomic_inc(&data->lost);
- perf_output_unlock(handle);
+ local_inc(&data->lost);
+ perf_output_put_handle(handle);
out:
rcu_read_unlock();
int wakeup_events = event->attr.wakeup_events;
if (handle->sample && wakeup_events) {
- int events = atomic_inc_return(&data->events);
+ int events = local_inc_return(&data->events);
if (events >= wakeup_events) {
- atomic_sub(wakeup_events, &data->events);
- atomic_set(&data->wakeup, 1);
+ local_sub(wakeup_events, &data->events);
+ local_inc(&data->wakeup);
}
}
- perf_output_unlock(handle);
+ perf_output_put_handle(handle);
rcu_read_unlock();
}
struct perf_task_event *task_event)
{
struct perf_output_handle handle;
- int size;
struct task_struct *task = task_event->task;
- int ret;
+ int size, ret;
size = task_event->event_id.header.size;
ret = perf_output_begin(&handle, event, size, 0, 0);
.event_id = {
.header = {
.type = PERF_RECORD_MMAP,
- .misc = 0,
+ .misc = PERF_RECORD_MISC_USER,
/* .size */
},
/* .pid */
}
}
-static void perf_swevent_unthrottle(struct perf_event *event)
-{
- /*
- * Nothing to do, we already reset hwc->interrupts.
- */
-}
-
static void perf_swevent_add(struct perf_event *event, u64 nr,
int nmi, struct perf_sample_data *data,
struct pt_regs *regs)
perf_swevent_overflow(event, 0, nmi, data, regs);
}
-static int perf_swevent_is_counting(struct perf_event *event)
-{
- /*
- * The event is active, we're good!
- */
- if (event->state == PERF_EVENT_STATE_ACTIVE)
- return 1;
-
- /*
- * The event is off/error, not counting.
- */
- if (event->state != PERF_EVENT_STATE_INACTIVE)
- return 0;
-
- /*
- * The event is inactive, if the context is active
- * we're part of a group that didn't make it on the 'pmu',
- * not counting.
- */
- if (event->ctx->is_active)
- return 0;
-
- /*
- * We're inactive and the context is too, this means the
- * task is scheduled out, we're counting events that happen
- * to us, like migration events.
- */
- return 1;
-}
-
-static int perf_tp_event_match(struct perf_event *event,
- struct perf_sample_data *data);
-
static int perf_exclude_event(struct perf_event *event,
struct pt_regs *regs)
{
struct perf_sample_data *data,
struct pt_regs *regs)
{
- if (event->cpu != -1 && event->cpu != smp_processor_id())
- return 0;
-
- if (!perf_swevent_is_counting(event))
- return 0;
-
if (event->attr.type != type)
return 0;
if (perf_exclude_event(event, regs))
return 0;
- if (event->attr.type == PERF_TYPE_TRACEPOINT &&
- !perf_tp_event_match(event, data))
- return 0;
-
return 1;
}
-static void perf_swevent_ctx_event(struct perf_event_context *ctx,
- enum perf_type_id type,
- u32 event_id, u64 nr, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
+static inline u64 swevent_hash(u64 type, u32 event_id)
+{
+ u64 val = event_id | (type << 32);
+
+ return hash_64(val, SWEVENT_HLIST_BITS);
+}
+
+static inline struct hlist_head *
+__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
+{
+ u64 hash = swevent_hash(type, event_id);
+
+ return &hlist->heads[hash];
+}
+
+/* For the read side: events when they trigger */
+static inline struct hlist_head *
+find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id)
+{
+ struct swevent_hlist *hlist;
+
+ hlist = rcu_dereference(ctx->swevent_hlist);
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+/* For the event head insertion and removal in the hlist */
+static inline struct hlist_head *
+find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event)
{
+ struct swevent_hlist *hlist;
+ u32 event_id = event->attr.config;
+ u64 type = event->attr.type;
+
+ /*
+ * Event scheduling is always serialized against hlist allocation
+ * and release. Which makes the protected version suitable here.
+ * The context lock guarantees that.
+ */
+ hlist = rcu_dereference_protected(ctx->swevent_hlist,
+ lockdep_is_held(&event->ctx->lock));
+ if (!hlist)
+ return NULL;
+
+ return __find_swevent_head(hlist, type, event_id);
+}
+
+static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
+ u64 nr, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ struct perf_cpu_context *cpuctx;
struct perf_event *event;
+ struct hlist_node *node;
+ struct hlist_head *head;
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ cpuctx = &__get_cpu_var(perf_cpu_context);
+
+ rcu_read_lock();
+
+ head = find_swevent_head_rcu(cpuctx, type, event_id);
+
+ if (!head)
+ goto end;
+
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
if (perf_swevent_match(event, type, event_id, data, regs))
perf_swevent_add(event, nr, nmi, data, regs);
}
+end:
+ rcu_read_unlock();
}
int perf_swevent_get_recursion_context(void)
{
- struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
+ struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
int rctx;
if (in_nmi())
else
rctx = 0;
- if (cpuctx->recursion[rctx]) {
- put_cpu_var(perf_cpu_context);
+ if (cpuctx->recursion[rctx])
return -1;
- }
cpuctx->recursion[rctx]++;
barrier();
struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
barrier();
cpuctx->recursion[rctx]--;
- put_cpu_var(perf_cpu_context);
}
EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
-static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
- u64 nr, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct perf_cpu_context *cpuctx;
- struct perf_event_context *ctx;
-
- cpuctx = &__get_cpu_var(perf_cpu_context);
- rcu_read_lock();
- perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
- nr, nmi, data, regs);
- /*
- * doesn't really matter which of the child contexts the
- * events ends up in.
- */
- ctx = rcu_dereference(current->perf_event_ctxp);
- if (ctx)
- perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
- rcu_read_unlock();
-}
void __perf_sw_event(u32 event_id, u64 nr, int nmi,
struct pt_regs *regs, u64 addr)
struct perf_sample_data data;
int rctx;
+ preempt_disable_notrace();
rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
return;
do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
perf_swevent_put_recursion_context(rctx);
+ preempt_enable_notrace();
}
static void perf_swevent_read(struct perf_event *event)
static int perf_swevent_enable(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
+ struct perf_cpu_context *cpuctx;
+ struct hlist_head *head;
+
+ cpuctx = &__get_cpu_var(perf_cpu_context);
if (hwc->sample_period) {
hwc->last_period = hwc->sample_period;
perf_swevent_set_period(event);
}
+
+ head = find_swevent_head(cpuctx, event);
+ if (WARN_ON_ONCE(!head))
+ return -EINVAL;
+
+ hlist_add_head_rcu(&event->hlist_entry, head);
+
return 0;
}
static void perf_swevent_disable(struct perf_event *event)
{
+ hlist_del_rcu(&event->hlist_entry);
+}
+
+static void perf_swevent_void(struct perf_event *event)
+{
+}
+
+static int perf_swevent_int(struct perf_event *event)
+{
+ return 0;
}
static const struct pmu perf_ops_generic = {
.enable = perf_swevent_enable,
.disable = perf_swevent_disable,
+ .start = perf_swevent_int,
+ .stop = perf_swevent_void,
.read = perf_swevent_read,
- .unthrottle = perf_swevent_unthrottle,
+ .unthrottle = perf_swevent_void, /* hwc->interrupts already reset */
};
/*
perf_sample_data_init(&data, 0);
data.period = event->hw.last_period;
regs = get_irq_regs();
- /*
- * In case we exclude kernel IPs or are somehow not in interrupt
- * context, provide the next best thing, the user IP.
- */
- if ((event->attr.exclude_kernel || !regs) &&
- !event->attr.exclude_user)
- regs = task_pt_regs(current);
- if (regs) {
+ if (regs && !perf_exclude_event(event, regs)) {
if (!(event->attr.exclude_idle && current->pid == 0))
if (perf_event_overflow(event, 0, &data, regs))
ret = HRTIMER_NORESTART;
.read = task_clock_perf_event_read,
};
-#ifdef CONFIG_EVENT_TRACING
+/* Deref the hlist from the update side */
+static inline struct swevent_hlist *
+swevent_hlist_deref(struct perf_cpu_context *cpuctx)
+{
+ return rcu_dereference_protected(cpuctx->swevent_hlist,
+ lockdep_is_held(&cpuctx->hlist_mutex));
+}
-void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
- int entry_size, struct pt_regs *regs)
+static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
{
- struct perf_sample_data data;
- struct perf_raw_record raw = {
- .size = entry_size,
- .data = record,
- };
+ struct swevent_hlist *hlist;
- perf_sample_data_init(&data, addr);
- data.raw = &raw;
+ hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
+ kfree(hlist);
+}
+
+static void swevent_hlist_release(struct perf_cpu_context *cpuctx)
+{
+ struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx);
- /* Trace events already protected against recursion */
- do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
- &data, regs);
+ if (!hlist)
+ return;
+
+ rcu_assign_pointer(cpuctx->swevent_hlist, NULL);
+ call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
}
-EXPORT_SYMBOL_GPL(perf_tp_event);
-static int perf_tp_event_match(struct perf_event *event,
+static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+
+ mutex_lock(&cpuctx->hlist_mutex);
+
+ if (!--cpuctx->hlist_refcount)
+ swevent_hlist_release(cpuctx);
+
+ mutex_unlock(&cpuctx->hlist_mutex);
+}
+
+static void swevent_hlist_put(struct perf_event *event)
+{
+ int cpu;
+
+ if (event->cpu != -1) {
+ swevent_hlist_put_cpu(event, event->cpu);
+ return;
+ }
+
+ for_each_possible_cpu(cpu)
+ swevent_hlist_put_cpu(event, cpu);
+}
+
+static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
+{
+ struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
+ int err = 0;
+
+ mutex_lock(&cpuctx->hlist_mutex);
+
+ if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+ if (!hlist) {
+ err = -ENOMEM;
+ goto exit;
+ }
+ rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
+ }
+ cpuctx->hlist_refcount++;
+ exit:
+ mutex_unlock(&cpuctx->hlist_mutex);
+
+ return err;
+}
+
+static int swevent_hlist_get(struct perf_event *event)
+{
+ int err;
+ int cpu, failed_cpu;
+
+ if (event->cpu != -1)
+ return swevent_hlist_get_cpu(event, event->cpu);
+
+ get_online_cpus();
+ for_each_possible_cpu(cpu) {
+ err = swevent_hlist_get_cpu(event, cpu);
+ if (err) {
+ failed_cpu = cpu;
+ goto fail;
+ }
+ }
+ put_online_cpus();
+
+ return 0;
+ fail:
+ for_each_possible_cpu(cpu) {
+ if (cpu == failed_cpu)
+ break;
+ swevent_hlist_put_cpu(event, cpu);
+ }
+
+ put_online_cpus();
+ return err;
+}
+
+#ifdef CONFIG_EVENT_TRACING
+
+static const struct pmu perf_ops_tracepoint = {
+ .enable = perf_trace_enable,
+ .disable = perf_trace_disable,
+ .start = perf_swevent_int,
+ .stop = perf_swevent_void,
+ .read = perf_swevent_read,
+ .unthrottle = perf_swevent_void,
+};
+
+static int perf_tp_filter_match(struct perf_event *event,
struct perf_sample_data *data)
{
void *record = data->raw->data;
return 0;
}
+static int perf_tp_event_match(struct perf_event *event,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ /*
+ * All tracepoints are from kernel-space.
+ */
+ if (event->attr.exclude_kernel)
+ return 0;
+
+ if (!perf_tp_filter_match(event, data))
+ return 0;
+
+ return 1;
+}
+
+void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
+ struct pt_regs *regs, struct hlist_head *head)
+{
+ struct perf_sample_data data;
+ struct perf_event *event;
+ struct hlist_node *node;
+
+ struct perf_raw_record raw = {
+ .size = entry_size,
+ .data = record,
+ };
+
+ perf_sample_data_init(&data, addr);
+ data.raw = &raw;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
+ if (perf_tp_event_match(event, &data, regs))
+ perf_swevent_add(event, count, 1, &data, regs);
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(perf_tp_event);
+
static void tp_perf_event_destroy(struct perf_event *event)
{
- perf_trace_disable(event->attr.config);
+ perf_trace_destroy(event);
}
static const struct pmu *tp_perf_event_init(struct perf_event *event)
{
+ int err;
+
/*
* Raw tracepoint data is a severe data leak, only allow root to
* have these.
!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
- if (perf_trace_enable(event->attr.config))
+ err = perf_trace_init(event);
+ if (err)
return NULL;
event->destroy = tp_perf_event_destroy;
- return &perf_ops_generic;
+ return &perf_ops_tracepoint;
}
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
#else
-static int perf_tp_event_match(struct perf_event *event,
- struct perf_sample_data *data)
-{
- return 1;
-}
-
static const struct pmu *tp_perf_event_init(struct perf_event *event)
{
return NULL;
WARN_ON(event->parent);
atomic_dec(&perf_swevent_enabled[event_id]);
+ swevent_hlist_put(event);
}
static const struct pmu *sw_perf_event_init(struct perf_event *event)
case PERF_COUNT_SW_ALIGNMENT_FAULTS:
case PERF_COUNT_SW_EMULATION_FAULTS:
if (!event->parent) {
+ int err;
+
+ err = swevent_hlist_get(event);
+ if (err)
+ return ERR_PTR(err);
+
atomic_inc(&perf_swevent_enabled[event_id]);
event->destroy = sw_perf_event_destroy;
}
goto out;
}
-static int perf_event_set_output(struct perf_event *event, int output_fd)
+static int
+perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
{
- struct perf_event *output_event = NULL;
- struct file *output_file = NULL;
- struct perf_event *old_output;
- int fput_needed = 0;
+ struct perf_mmap_data *data = NULL, *old_data = NULL;
int ret = -EINVAL;
- if (!output_fd)
+ if (!output_event)
goto set;
- output_file = fget_light(output_fd, &fput_needed);
- if (!output_file)
- return -EBADF;
-
- if (output_file->f_op != &perf_fops)
+ /* don't allow circular references */
+ if (event == output_event)
goto out;
- output_event = output_file->private_data;
-
- /* Don't chain output fds */
- if (output_event->output)
+ /*
+ * Don't allow cross-cpu buffers
+ */
+ if (output_event->cpu != event->cpu)
goto out;
- /* Don't set an output fd when we already have an output channel */
- if (event->data)
+ /*
+ * If its not a per-cpu buffer, it must be the same task.
+ */
+ if (output_event->cpu == -1 && output_event->ctx != event->ctx)
goto out;
- atomic_long_inc(&output_file->f_count);
-
set:
mutex_lock(&event->mmap_mutex);
- old_output = event->output;
- rcu_assign_pointer(event->output, output_event);
- mutex_unlock(&event->mmap_mutex);
+ /* Can't redirect output if we've got an active mmap() */
+ if (atomic_read(&event->mmap_count))
+ goto unlock;
- if (old_output) {
- /*
- * we need to make sure no existing perf_output_*()
- * is still referencing this event.
- */
- synchronize_rcu();
- fput(old_output->filp);
+ if (output_event) {
+ /* get the buffer we want to redirect to */
+ data = perf_mmap_data_get(output_event);
+ if (!data)
+ goto unlock;
}
+ old_data = event->data;
+ rcu_assign_pointer(event->data, data);
ret = 0;
+unlock:
+ mutex_unlock(&event->mmap_mutex);
+
+ if (old_data)
+ perf_mmap_data_put(old_data);
out:
- fput_light(output_file, fput_needed);
return ret;
}
struct perf_event_attr __user *, attr_uptr,
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
{
- struct perf_event *event, *group_leader;
+ struct perf_event *event, *group_leader = NULL, *output_event = NULL;
struct perf_event_attr attr;
struct perf_event_context *ctx;
struct file *event_file = NULL;
struct file *group_file = NULL;
+ int event_fd;
int fput_needed = 0;
- int fput_needed2 = 0;
int err;
/* for future expandability... */
return -EINVAL;
}
+ event_fd = get_unused_fd_flags(O_RDWR);
+ if (event_fd < 0)
+ return event_fd;
+
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(pid, cpu);
- if (IS_ERR(ctx))
- return PTR_ERR(ctx);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto err_fd;
+ }
+
+ if (group_fd != -1) {
+ group_leader = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_leader)) {
+ err = PTR_ERR(group_leader);
+ goto err_put_context;
+ }
+ group_file = group_leader->filp;
+ if (flags & PERF_FLAG_FD_OUTPUT)
+ output_event = group_leader;
+ if (flags & PERF_FLAG_FD_NO_GROUP)
+ group_leader = NULL;
+ }
/*
* Look up the group leader (we will attach this event to it):
*/
- group_leader = NULL;
- if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
+ if (group_leader) {
err = -EINVAL;
- group_file = fget_light(group_fd, &fput_needed);
- if (!group_file)
- goto err_put_context;
- if (group_file->f_op != &perf_fops)
- goto err_put_context;
- group_leader = group_file->private_data;
/*
* Do not allow a recursive hierarchy (this new sibling
* becoming part of another group-sibling):
event = perf_event_alloc(&attr, cpu, ctx, group_leader,
NULL, NULL, GFP_KERNEL);
- err = PTR_ERR(event);
- if (IS_ERR(event))
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
goto err_put_context;
+ }
- err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
- if (err < 0)
- goto err_free_put_context;
+ if (output_event) {
+ err = perf_event_set_output(event, output_event);
+ if (err)
+ goto err_free_put_context;
+ }
- event_file = fget_light(err, &fput_needed2);
- if (!event_file)
+ event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
+ if (IS_ERR(event_file)) {
+ err = PTR_ERR(event_file);
goto err_free_put_context;
-
- if (flags & PERF_FLAG_FD_OUTPUT) {
- err = perf_event_set_output(event, group_fd);
- if (err)
- goto err_fput_free_put_context;
}
event->filp = event_file;
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
mutex_unlock(¤t->perf_event_mutex);
-err_fput_free_put_context:
- fput_light(event_file, fput_needed2);
+ /*
+ * Drop the reference on the group_event after placing the
+ * new event on the sibling_list. This ensures destruction
+ * of the group leader will find the pointer to itself in
+ * perf_group_detach().
+ */
+ fput_light(group_file, fput_needed);
+ fd_install(event_fd, event_file);
+ return event_fd;
err_free_put_context:
- if (err < 0)
- kfree(event);
-
+ free_event(event);
err_put_context:
- if (err < 0)
- put_ctx(ctx);
-
fput_light(group_file, fput_needed);
-
+ put_ctx(ctx);
+err_fd:
+ put_unused_fd(event_fd);
return err;
}
*
* But since its the parent context it won't be the same instance.
*/
- mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
+ mutex_lock(&child_ctx->mutex);
again:
list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
fput(parent->filp);
+ perf_group_detach(event);
list_del_event(event, ctx);
free_event(event);
}
for_each_possible_cpu(cpu) {
cpuctx = &per_cpu(perf_cpu_context, cpu);
+ mutex_init(&cpuctx->hlist_mutex);
__perf_event_init_context(&cpuctx->ctx, NULL);
}
}
spin_lock(&perf_resource_lock);
cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
spin_unlock(&perf_resource_lock);
+
+ mutex_lock(&cpuctx->hlist_mutex);
+ if (cpuctx->hlist_refcount > 0) {
+ struct swevent_hlist *hlist;
+
+ hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+ WARN_ON_ONCE(!hlist);
+ rcu_assign_pointer(cpuctx->swevent_hlist, hlist);
+ }
+ mutex_unlock(&cpuctx->hlist_mutex);
}
#ifdef CONFIG_HOTPLUG_CPU
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
struct perf_event_context *ctx = &cpuctx->ctx;
+ mutex_lock(&cpuctx->hlist_mutex);
+ swevent_hlist_release(cpuctx);
+ mutex_unlock(&cpuctx->hlist_mutex);
+
mutex_lock(&ctx->mutex);
smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
mutex_unlock(&ctx->mutex);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff