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: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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@ -1290,20 +1290,20 @@ out:
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}
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/*
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* The function below uses __get_free_page to allocate a pipeline stage, along
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* with all the necessary small buffers which together make a buffer of size
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* The function below uses __get_free_pages to allocate a data buffer of size
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* tape->stage_size (or a bit more). We attempt to combine sequential pages as
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* much as possible.
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*
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* It returns a pointer to the new allocated stage, or NULL if we can't (or
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* don't want to) allocate a stage.
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* It returns a pointer to the newly allocated buffer, or NULL in case of
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* failure.
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*/
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static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
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static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,
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int clear)
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{
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idetape_stage_t *stage;
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struct idetape_bh *prev_bh, *bh;
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int pages = tape->pages_per_stage;
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unsigned int order, b_allocd;
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char *b_data = NULL;
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stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
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@ -1315,46 +1315,60 @@ static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
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bh = stage->bh;
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if (bh == NULL)
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goto abort;
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bh->b_reqnext = NULL;
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bh->b_data = (char *) __get_free_page(GFP_KERNEL);
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order = fls(pages) - 1;
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bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
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if (!bh->b_data)
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goto abort;
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b_allocd = (1 << order) * PAGE_SIZE;
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pages &= (order-1);
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if (clear)
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memset(bh->b_data, 0, PAGE_SIZE);
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bh->b_size = PAGE_SIZE;
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memset(bh->b_data, 0, b_allocd);
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bh->b_reqnext = NULL;
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bh->b_size = b_allocd;
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atomic_set(&bh->b_count, full ? bh->b_size : 0);
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while (--pages) {
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b_data = (char *) __get_free_page(GFP_KERNEL);
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while (pages) {
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order = fls(pages) - 1;
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b_data = (char *) __get_free_pages(GFP_KERNEL, order);
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if (!b_data)
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goto abort;
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b_allocd = (1 << order) * PAGE_SIZE;
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if (clear)
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memset(b_data, 0, PAGE_SIZE);
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if (bh->b_data == b_data + PAGE_SIZE) {
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bh->b_size += PAGE_SIZE;
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bh->b_data -= PAGE_SIZE;
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memset(b_data, 0, b_allocd);
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/* newly allocated page frames below buffer header or ...*/
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if (bh->b_data == b_data + b_allocd) {
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bh->b_size += b_allocd;
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bh->b_data -= b_allocd;
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if (full)
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atomic_add(PAGE_SIZE, &bh->b_count);
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atomic_add(b_allocd, &bh->b_count);
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continue;
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}
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/* they are above the header */
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if (b_data == bh->b_data + bh->b_size) {
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bh->b_size += PAGE_SIZE;
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bh->b_size += b_allocd;
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if (full)
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atomic_add(PAGE_SIZE, &bh->b_count);
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atomic_add(b_allocd, &bh->b_count);
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continue;
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}
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prev_bh = bh;
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bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
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if (!bh) {
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free_page((unsigned long) b_data);
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free_pages((unsigned long) b_data, order);
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goto abort;
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}
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bh->b_reqnext = NULL;
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bh->b_data = b_data;
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bh->b_size = PAGE_SIZE;
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bh->b_size = b_allocd;
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atomic_set(&bh->b_count, full ? bh->b_size : 0);
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prev_bh->b_reqnext = bh;
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pages &= (order-1);
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}
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bh->b_size -= tape->excess_bh_size;
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if (full)
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atomic_sub(tape->excess_bh_size, &bh->b_count);
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@ -1837,7 +1851,7 @@ static int idetape_init_read(ide_drive_t *drive)
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" 0 now\n");
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tape->merge_stage_size = 0;
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}
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tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
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tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);
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if (!tape->merge_stage)
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return -ENOMEM;
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tape->chrdev_dir = IDETAPE_DIR_READ;
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@ -2115,7 +2129,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
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"should be 0 now\n");
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tape->merge_stage_size = 0;
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}
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tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
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tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);
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if (!tape->merge_stage)
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return -ENOMEM;
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tape->chrdev_dir = IDETAPE_DIR_WRITE;
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@ -2495,7 +2509,7 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
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idetape_tape_t *tape = drive->driver_data;
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idetape_empty_write_pipeline(drive);
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tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
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tape->merge_stage = ide_tape_kmalloc_buffer(tape, 1, 0);
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if (tape->merge_stage != NULL) {
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idetape_pad_zeros(drive, tape->blk_size *
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(tape->user_bs_factor - 1));
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