From 41aa17069ea8d2b5cd2ca1ef7ff6cdb7c6abec95 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 27 Apr 2008 15:38:32 +0200 Subject: [PATCH] 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 Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-tape.c | 60 ++++++++++++++++++++++++++---------------- 1 file changed, 37 insertions(+), 23 deletions(-) diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index 2275cd22902..dc7abb25a8e 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -1290,20 +1290,20 @@ out: } /* - * 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)); -- 2.41.1