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Commit 41aa1706 authored by Borislav Petkov's avatar Borislav Petkov Committed by Bartlomiej Zolnierkiewicz
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ide-tape: improve buffer allocation strategy 



Instead of allocating pages for the buffer one by one, take advantage of the
buddy alloc system and request them 2^order at a time. This increases the chance
for bigger buffer parts to be contigious and reduces loop iteration count. While
at it, rename function __idetape_kmalloc_stage() to ide_tape_kmalloc_buffer().

[bart: fold with "ide-tape: fix mem leak" patch to preserve bisectability]

Signed-off-by: default avatarBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
parent 4c3032d8

drivers/ide/ide-tape.c

+37 −23
Original line number Diff line number Diff line
@@ -1290,20 +1290,20 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, 
}



/*

 * The function below uses __get_free_page to allocate a pipeline stage, along

 * with all the necessary small buffers which together make a buffer of size

 * The function below uses __get_free_pages to allocate a data buffer of size

 * tape->stage_size (or a bit more). We attempt to combine sequential pages as

 * much as possible.

 *

 * It returns a pointer to the new allocated stage, or NULL if we can't (or

 * don't want to) allocate a stage.

 * It returns a pointer to the newly allocated buffer, or NULL in case of

 * failure.

 */

static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,

static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,

						int clear)

{

	idetape_stage_t *stage;

	struct idetape_bh *prev_bh, *bh;

	int pages = tape->pages_per_stage;

	unsigned int order, b_allocd;

	char *b_data = NULL;



	stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
@@ -1315,46 +1315,60 @@ static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full, 
	bh = stage->bh;

	if (bh == NULL)

		goto abort;

	bh->b_reqnext = NULL;

	bh->b_data = (char *) __get_free_page(GFP_KERNEL);



	order = fls(pages) - 1;

	bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);

	if (!bh->b_data)

		goto abort;

	b_allocd = (1 << order) * PAGE_SIZE;

	pages &= (order-1);



	if (clear)

		memset(bh->b_data, 0, PAGE_SIZE);

	bh->b_size = PAGE_SIZE;

		memset(bh->b_data, 0, b_allocd);

	bh->b_reqnext = NULL;

	bh->b_size = b_allocd;

	atomic_set(&bh->b_count, full ? bh->b_size : 0);



	while (--pages) {

		b_data = (char *) __get_free_page(GFP_KERNEL);

	while (pages) {

		order = fls(pages) - 1;

		b_data = (char *) __get_free_pages(GFP_KERNEL, order);

		if (!b_data)

			goto abort;

		b_allocd = (1 << order) * PAGE_SIZE;



		if (clear)

			memset(b_data, 0, PAGE_SIZE);

		if (bh->b_data == b_data + PAGE_SIZE) {

			bh->b_size += PAGE_SIZE;

			bh->b_data -= PAGE_SIZE;

			memset(b_data, 0, b_allocd);



		/* newly allocated page frames below buffer header or ...*/

		if (bh->b_data == b_data + b_allocd) {

			bh->b_size += b_allocd;

			bh->b_data -= b_allocd;

			if (full)

				atomic_add(PAGE_SIZE, &bh->b_count);

				atomic_add(b_allocd, &bh->b_count);

			continue;

		}

		/* they are above the header */

		if (b_data == bh->b_data + bh->b_size) {

			bh->b_size += PAGE_SIZE;

			bh->b_size += b_allocd;

			if (full)

				atomic_add(PAGE_SIZE, &bh->b_count);

				atomic_add(b_allocd, &bh->b_count);

			continue;

		}

		prev_bh = bh;

		bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);

		if (!bh) {

			free_page((unsigned long) b_data);

			free_pages((unsigned long) b_data, order);

			goto abort;

		}

		bh->b_reqnext = NULL;

		bh->b_data = b_data;

		bh->b_size = PAGE_SIZE;

		bh->b_size = b_allocd;

		atomic_set(&bh->b_count, full ? bh->b_size : 0);

		prev_bh->b_reqnext = bh;



		pages &= (order-1);

	}



	bh->b_size -= tape->excess_bh_size;

	if (full)

		atomic_sub(tape->excess_bh_size, &bh->b_count);
@@ -1837,7 +1851,7 @@ static int idetape_init_read(ide_drive_t *drive) 
					 " 0 now\n");

			tape->merge_stage_size = 0;

		}

		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);

		tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);

		if (!tape->merge_stage)

			return -ENOMEM;

		tape->chrdev_dir = IDETAPE_DIR_READ;
@@ -2115,7 +2129,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, 
				"should be 0 now\n");

			tape->merge_stage_size = 0;

		}

		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);

		tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);

		if (!tape->merge_stage)

			return -ENOMEM;

		tape->chrdev_dir = IDETAPE_DIR_WRITE;
@@ -2495,7 +2509,7 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor) 
	idetape_tape_t *tape = drive->driver_data;



	idetape_empty_write_pipeline(drive);

	tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);

	tape->merge_stage = ide_tape_kmalloc_buffer(tape, 1, 0);

	if (tape->merge_stage != NULL) {

		idetape_pad_zeros(drive, tape->blk_size *

				(tape->user_bs_factor - 1));