[PATCH 10/16] drm/amdkfd: Simplify events page allocator
Felix Kuehling
Felix.Kuehling at amd.com
Sat Oct 21 00:23:14 UTC 2017
The first event page is always big enough to handle all events.
Handling of multiple events pages is not supported by user mode, and
not necessary.
Signed-off-by: Yong Zhao <yong.zhao at amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
drivers/gpu/drm/amd/amdkfd/kfd_events.c | 197 +++++++++++---------------------
drivers/gpu/drm/amd/amdkfd/kfd_events.h | 1 -
drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 4 +-
3 files changed, 70 insertions(+), 132 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index f178248..f800e48 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -41,6 +41,9 @@ struct kfd_event_waiter {
bool activated; /* Becomes true when event is signaled */
};
+#define SLOTS_PER_PAGE KFD_SIGNAL_EVENT_LIMIT
+#define SLOT_BITMAP_LONGS BITS_TO_LONGS(SLOTS_PER_PAGE)
+
/*
* Over-complicated pooled allocator for event notification slots.
*
@@ -51,132 +54,98 @@ struct kfd_event_waiter {
* Individual signal events are then allocated a slot in a page.
*/
-struct signal_page {
- struct list_head event_pages; /* kfd_process.signal_event_pages */
+struct kfd_signal_page {
uint64_t *kernel_address;
uint64_t __user *user_address;
- uint32_t page_index; /* Index into the mmap aperture. */
unsigned int free_slots;
- unsigned long used_slot_bitmap[0];
+ unsigned long used_slot_bitmap[SLOT_BITMAP_LONGS];
};
-#define SLOTS_PER_PAGE KFD_SIGNAL_EVENT_LIMIT
-#define SLOT_BITMAP_SIZE BITS_TO_LONGS(SLOTS_PER_PAGE)
-#define BITS_PER_PAGE (ilog2(SLOTS_PER_PAGE)+1)
-#define SIGNAL_PAGE_SIZE (sizeof(struct signal_page) + \
- SLOT_BITMAP_SIZE * sizeof(long))
-
/*
* For signal events, the event ID is used as the interrupt user data.
* For SQ s_sendmsg interrupts, this is limited to 8 bits.
*/
#define INTERRUPT_DATA_BITS 12
-#define SIGNAL_EVENT_ID_SLOT_SHIFT 0
-static uint64_t *page_slots(struct signal_page *page)
+static uint64_t *page_slots(struct kfd_signal_page *page)
{
return page->kernel_address;
}
static bool allocate_free_slot(struct kfd_process *process,
- struct signal_page **out_page,
- unsigned int *out_slot_index)
+ unsigned int *out_slot_index)
{
- struct signal_page *page;
+ struct kfd_signal_page *page = process->signal_page;
+ unsigned int slot;
- list_for_each_entry(page, &process->signal_event_pages, event_pages) {
- if (page->free_slots > 0) {
- unsigned int slot =
- find_first_zero_bit(page->used_slot_bitmap,
- SLOTS_PER_PAGE);
+ if (!page || page->free_slots == 0) {
+ pr_debug("No free event signal slots were found for process %p\n",
+ process);
- __set_bit(slot, page->used_slot_bitmap);
- page->free_slots--;
+ return false;
+ }
- page_slots(page)[slot] = UNSIGNALED_EVENT_SLOT;
+ slot = find_first_zero_bit(page->used_slot_bitmap, SLOTS_PER_PAGE);
- *out_page = page;
- *out_slot_index = slot;
+ __set_bit(slot, page->used_slot_bitmap);
+ page->free_slots--;
- pr_debug("Allocated event signal slot in page %p, slot %d\n",
- page, slot);
+ page_slots(page)[slot] = UNSIGNALED_EVENT_SLOT;
- return true;
- }
- }
+ *out_slot_index = slot;
- pr_debug("No free event signal slots were found for process %p\n",
- process);
+ pr_debug("Allocated event signal slot in page %p, slot %d\n",
+ page, slot);
- return false;
+ return true;
}
-#define list_tail_entry(head, type, member) \
- list_entry((head)->prev, type, member)
-
-static bool allocate_signal_page(struct file *devkfd, struct kfd_process *p)
+static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
{
void *backing_store;
- struct signal_page *page;
+ struct kfd_signal_page *page;
- page = kzalloc(SIGNAL_PAGE_SIZE, GFP_KERNEL);
+ page = kzalloc(sizeof(*page), GFP_KERNEL);
if (!page)
- goto fail_alloc_signal_page;
+ return NULL;
page->free_slots = SLOTS_PER_PAGE;
- backing_store = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ backing_store = (void *) __get_free_pages(GFP_KERNEL,
get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
if (!backing_store)
goto fail_alloc_signal_store;
- /* prevent user-mode info leaks */
+ /* Initialize all events to unsignaled */
memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
- KFD_SIGNAL_EVENT_LIMIT * 8);
+ KFD_SIGNAL_EVENT_LIMIT * 8);
page->kernel_address = backing_store;
-
- if (list_empty(&p->signal_event_pages))
- page->page_index = 0;
- else
- page->page_index = list_tail_entry(&p->signal_event_pages,
- struct signal_page,
- event_pages)->page_index + 1;
-
pr_debug("Allocated new event signal page at %p, for process %p\n",
page, p);
- pr_debug("Page index is %d\n", page->page_index);
-
- list_add(&page->event_pages, &p->signal_event_pages);
- return true;
+ return page;
fail_alloc_signal_store:
kfree(page);
-fail_alloc_signal_page:
- return false;
+ return NULL;
}
-static bool allocate_event_notification_slot(struct file *devkfd,
- struct kfd_process *p,
- struct signal_page **page,
- unsigned int *signal_slot_index)
+static bool allocate_event_notification_slot(struct kfd_process *p,
+ unsigned int *signal_slot_index)
{
- bool ret;
-
- ret = allocate_free_slot(p, page, signal_slot_index);
- if (!ret) {
- ret = allocate_signal_page(devkfd, p);
- if (ret)
- ret = allocate_free_slot(p, page, signal_slot_index);
+ if (!p->signal_page) {
+ p->signal_page = allocate_signal_page(p);
+ if (!p->signal_page)
+ return false;
}
- return ret;
+ return allocate_free_slot(p, signal_slot_index);
}
/* Assumes that the process's event_mutex is locked. */
-static void release_event_notification_slot(struct signal_page *page,
+static void release_event_notification_slot(struct kfd_signal_page *page,
size_t slot_index)
{
__clear_bit(slot_index, page->used_slot_bitmap);
@@ -187,22 +156,6 @@ static void release_event_notification_slot(struct signal_page *page,
*/
}
-static struct signal_page *lookup_signal_page_by_index(struct kfd_process *p,
- unsigned int page_index)
-{
- struct signal_page *page;
-
- /*
- * This is safe because we don't delete signal pages until the
- * process exits.
- */
- list_for_each_entry(page, &p->signal_event_pages, event_pages)
- if (page->page_index == page_index)
- return page;
-
- return NULL;
-}
-
/*
* Assumes that p->event_mutex is held and of course that p is not going
* away (current or locked).
@@ -218,13 +171,6 @@ static struct kfd_event *lookup_event_by_id(struct kfd_process *p, uint32_t id)
return NULL;
}
-static u32 make_signal_event_id(struct signal_page *page,
- unsigned int signal_slot_index)
-{
- return page->page_index |
- (signal_slot_index << SIGNAL_EVENT_ID_SLOT_SHIFT);
-}
-
/*
* Produce a kfd event id for a nonsignal event.
* These are arbitrary numbers, so we do a sequential search through
@@ -270,10 +216,9 @@ static u32 make_nonsignal_event_id(struct kfd_process *p)
}
static struct kfd_event *lookup_event_by_page_slot(struct kfd_process *p,
- struct signal_page *page,
unsigned int signal_slot)
{
- return lookup_event_by_id(p, make_signal_event_id(page, signal_slot));
+ return lookup_event_by_id(p, signal_slot);
}
static int create_signal_event(struct file *devkfd,
@@ -288,8 +233,7 @@ static int create_signal_event(struct file *devkfd,
return -ENOMEM;
}
- if (!allocate_event_notification_slot(devkfd, p, &ev->signal_page,
- &ev->signal_slot_index)) {
+ if (!allocate_event_notification_slot(p, &ev->signal_slot_index)) {
pr_warn("Signal event wasn't created because out of kernel memory\n");
return -ENOMEM;
}
@@ -297,10 +241,9 @@ static int create_signal_event(struct file *devkfd,
p->signal_event_count++;
ev->user_signal_address =
- &ev->signal_page->user_address[ev->signal_slot_index];
+ &p->signal_page->user_address[ev->signal_slot_index];
- ev->event_id = make_signal_event_id(ev->signal_page,
- ev->signal_slot_index);
+ ev->event_id = ev->signal_slot_index;
pr_debug("Signal event number %zu created with id %d, address %p\n",
p->signal_event_count, ev->event_id,
@@ -327,7 +270,7 @@ void kfd_event_init_process(struct kfd_process *p)
{
mutex_init(&p->event_mutex);
hash_init(p->events);
- INIT_LIST_HEAD(&p->signal_event_pages);
+ p->signal_page = NULL;
p->next_nonsignal_event_id = KFD_FIRST_NONSIGNAL_EVENT_ID;
p->signal_event_count = 0;
}
@@ -341,8 +284,9 @@ static void destroy_event(struct kfd_process *p, struct kfd_event *ev)
waiter->event = NULL;
wake_up_all(&ev->wq);
- if (ev->signal_page) {
- release_event_notification_slot(ev->signal_page,
+ if ((ev->type == KFD_EVENT_TYPE_SIGNAL ||
+ ev->type == KFD_EVENT_TYPE_DEBUG) && p->signal_page) {
+ release_event_notification_slot(p->signal_page,
ev->signal_slot_index);
p->signal_event_count--;
}
@@ -365,12 +309,11 @@ static void destroy_events(struct kfd_process *p)
* We assume that the process is being destroyed and there is no need to
* unmap the pages or keep bookkeeping data in order.
*/
-static void shutdown_signal_pages(struct kfd_process *p)
+static void shutdown_signal_page(struct kfd_process *p)
{
- struct signal_page *page, *tmp;
+ struct kfd_signal_page *page = p->signal_page;
- list_for_each_entry_safe(page, tmp, &p->signal_event_pages,
- event_pages) {
+ if (page) {
free_pages((unsigned long)page->kernel_address,
get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
kfree(page);
@@ -380,7 +323,7 @@ static void shutdown_signal_pages(struct kfd_process *p)
void kfd_event_free_process(struct kfd_process *p)
{
destroy_events(p);
- shutdown_signal_pages(p);
+ shutdown_signal_page(p);
}
static bool event_can_be_gpu_signaled(const struct kfd_event *ev)
@@ -420,8 +363,7 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
case KFD_EVENT_TYPE_DEBUG:
ret = create_signal_event(devkfd, p, ev);
if (!ret) {
- *event_page_offset = (ev->signal_page->page_index |
- KFD_MMAP_EVENTS_MASK);
+ *event_page_offset = KFD_MMAP_EVENTS_MASK;
*event_page_offset <<= PAGE_SHIFT;
*event_slot_index = ev->signal_slot_index;
}
@@ -523,13 +465,17 @@ int kfd_reset_event(struct kfd_process *p, uint32_t event_id)
static void acknowledge_signal(struct kfd_process *p, struct kfd_event *ev)
{
- page_slots(ev->signal_page)[ev->signal_slot_index] =
+ page_slots(p->signal_page)[ev->signal_slot_index] =
UNSIGNALED_EVENT_SLOT;
}
-static bool is_slot_signaled(struct signal_page *page, unsigned int index)
+static bool is_slot_signaled(struct kfd_process *p, unsigned int index)
{
- return page_slots(page)[index] != UNSIGNALED_EVENT_SLOT;
+ if (!p->signal_page)
+ return false;
+ else
+ return page_slots(p->signal_page)[index] !=
+ UNSIGNALED_EVENT_SLOT;
}
static void set_event_from_interrupt(struct kfd_process *p,
@@ -562,22 +508,19 @@ void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
/* Partial ID is a full ID. */
ev = lookup_event_by_id(p, partial_id);
set_event_from_interrupt(p, ev);
- } else {
+ } else if (p->signal_page) {
/*
* Partial ID is in fact partial. For now we completely
* ignore it, but we could use any bits we did receive to
* search faster.
*/
- struct signal_page *page;
unsigned int i;
- list_for_each_entry(page, &p->signal_event_pages, event_pages)
- for (i = 0; i < SLOTS_PER_PAGE; i++)
- if (is_slot_signaled(page, i)) {
- ev = lookup_event_by_page_slot(p,
- page, i);
- set_event_from_interrupt(p, ev);
- }
+ for (i = 0; i < SLOTS_PER_PAGE; i++)
+ if (is_slot_signaled(p, i)) {
+ ev = lookup_event_by_page_slot(p, i);
+ set_event_from_interrupt(p, ev);
+ }
}
mutex_unlock(&p->event_mutex);
@@ -842,9 +785,8 @@ int kfd_wait_on_events(struct kfd_process *p,
int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
{
- unsigned int page_index;
unsigned long pfn;
- struct signal_page *page;
+ struct kfd_signal_page *page;
/* check required size is logical */
if (get_order(KFD_SIGNAL_EVENT_LIMIT * 8) !=
@@ -853,13 +795,10 @@ int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
return -EINVAL;
}
- page_index = vma->vm_pgoff;
-
- page = lookup_signal_page_by_index(p, page_index);
+ page = p->signal_page;
if (!page) {
/* Probably KFD bug, but mmap is user-accessible. */
- pr_debug("Signal page could not be found for page_index %u\n",
- page_index);
+ pr_debug("Signal page could not be found\n");
return -EINVAL;
}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.h b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
index 96f9122..f85fcee 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
@@ -60,7 +60,6 @@ struct kfd_event {
wait_queue_head_t wq; /* List of event waiters. */
/* Only for signal events. */
- struct signal_page *signal_page;
unsigned int signal_slot_index;
uint64_t __user *user_signal_address;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index d3cf53a..c1b3ee2 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -540,8 +540,8 @@ struct kfd_process {
struct mutex event_mutex;
/* All events in process hashed by ID, linked on kfd_event.events. */
DECLARE_HASHTABLE(events, 4);
- /* struct slot_page_header.event_pages */
- struct list_head signal_event_pages;
+ /* Event page */
+ struct kfd_signal_page *signal_page;
u32 next_nonsignal_event_id;
size_t signal_event_count;
bool signal_event_limit_reached;
--
2.7.4
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