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Commit 3cafa9fb authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf: Optimize the !vmalloc backed buffer 



Reduce code and data by using the knowledge that for
!PERF_USE_VMALLOC data_order is always 0.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100521090710.795019386@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5d967a8b

include/linux/perf_event.h

+1 −1
Original line number Diff line number Diff line
@@ -588,8 +588,8 @@ struct perf_mmap_data { 
	struct rcu_head			rcu_head;

#ifdef CONFIG_PERF_USE_VMALLOC

	struct work_struct		work;

	int				page_order;	/* allocation order  */

#endif

	int				data_order;	/* allocation order  */

	int				nr_pages;	/* nr of data pages  */

	int				writable;	/* are we writable   */

	int				nr_locked;	/* nr pages mlocked  */

kernel/perf_event.c

+26 −15
Original line number Diff line number Diff line
@@ -2297,11 +2297,6 @@ void perf_event_update_userpage(struct perf_event *event) 
	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



/*
@@ -2359,7 +2354,6 @@ perf_mmap_data_alloc(struct perf_event *event, int nr_pages) 
			goto fail_data_pages;

	}



	data->data_order = 0;

	data->nr_pages = nr_pages;



	return data;
@@ -2395,6 +2389,11 @@ static void perf_mmap_data_free(struct perf_mmap_data *data) 
	kfree(data);

}



static inline int page_order(struct perf_mmap_data *data)

{

	return 0;

}



#else



/*
@@ -2403,10 +2402,15 @@ static void perf_mmap_data_free(struct perf_mmap_data *data) 
 * 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);
@@ -2426,7 +2430,7 @@ static void perf_mmap_data_free_work(struct work_struct *work) 
	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++)
@@ -2465,7 +2469,7 @@ perf_mmap_data_alloc(struct perf_event *event, int nr_pages) 


	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;
@@ -2479,6 +2483,11 @@ perf_mmap_data_alloc(struct perf_event *event, int nr_pages) 


#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;
@@ -2979,10 +2988,12 @@ void perf_output_copy(struct perf_output_handle *handle, 
		handle->addr += size;

		handle->size -= size;

		if (!handle->size) {

			struct perf_mmap_data *data = handle->data;



			handle->page++;

			handle->page &= handle->data->nr_pages - 1;

			handle->addr = handle->data->data_pages[handle->page];

			handle->size = PAGE_SIZE << handle->data->data_order;

			handle->page &= data->nr_pages - 1;

			handle->addr = data->data_pages[handle->page];

			handle->size = PAGE_SIZE << page_order(data);

		}

	} while (len);

}
@@ -3050,12 +3061,12 @@ int perf_output_begin(struct perf_output_handle *handle, 
	if (head - local_read(&data->wakeup) > data->watermark)

		local_add(data->watermark, &data->wakeup);



	handle->page = handle->offset >> (PAGE_SHIFT + data->data_order);

	handle->page = handle->offset >> (PAGE_SHIFT + page_order(data));

	handle->page &= data->nr_pages - 1;

	handle->size = handle->offset & ((PAGE_SIZE << data->data_order) - 1);

	handle->size = handle->offset & ((PAGE_SIZE << page_order(data)) - 1);

	handle->addr = data->data_pages[handle->page];

	handle->addr += handle->size;

	handle->size = (PAGE_SIZE << data->data_order) - handle->size;

	handle->size = (PAGE_SIZE << page_order(data)) - handle->size;



	if (have_lost) {

		lost_event.header.type = PERF_RECORD_LOST;