On Monday, November 22, 2010, Bojan Smojver wrote:
> Hi Rafael,
>
> This is a fix for reading LZO compressed image using async I/O.
> Essentially, instead of having just one page into which we keep reading
> blocks from swap, we allocate enough of them to cover the largest
> compressed size and then let block I/O pick them all up. Once we have
> them all (and here we wait), we decompress them, as usual. Obviously,
> the very first block we still pick up synchronously, because we need to
> know the size of the lot before we pick up the rest.
>
> I guess this can go in 2.6.37 (actually, this is how I _should_ have
> done that patch in the first place), because it is essentially a
> performance fix.
>
> Also fixed the copyright line, which I've forgotten before.
Applied to suspend-2.6/linux-next.
Thanks,
Rafael
> kernel/power/swap.c | 53
> ++++++++++++++++++++++++++++++++++++--------------
> 1 files changed, 38 insertions(+), 15 deletions(-)
>
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index a0e4a86..baf667b 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -6,6 +6,7 @@
> *
> * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@xxxxxx>
> * Copyright (C) 2006 Rafael J. Wysocki <rjw@xxxxxxx>
> + * Copyright (C) 2010 Bojan Smojver <bojan@xxxxxxxxxxxxx>
> *
> * This file is released under the GPLv2.
> *
> @@ -753,30 +754,43 @@ static int load_image_lzo(struct swap_map_handle
> *handle,
> {
> unsigned int m;
> int error = 0;
> + struct bio *bio;
> struct timeval start;
> struct timeval stop;
> unsigned nr_pages;
> - size_t off, unc_len, cmp_len;
> - unsigned char *unc, *cmp, *page;
> + size_t i, off, unc_len, cmp_len;
> + unsigned char *unc, *cmp, *page[LZO_CMP_PAGES];
>
> - page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
> - if (!page) {
> - printk(KERN_ERR "PM: Failed to allocate LZO page\n");
> - return -ENOMEM;
> + for (i = 0; i < LZO_CMP_PAGES; i++) {
> + page[i] = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
> + if (!page[i]) {
> + printk(KERN_ERR "PM: Failed to allocate LZO page\n");
> +
> + while (i)
> + free_page((unsigned long)page[--i]);
> +
> + return -ENOMEM;
> + }
> }
>
> unc = vmalloc(LZO_UNC_SIZE);
> if (!unc) {
> printk(KERN_ERR "PM: Failed to allocate LZO uncompressed\n");
> - free_page((unsigned long)page);
> +
> + for (i = 0; i < LZO_CMP_PAGES; i++)
> + free_page((unsigned long)page[i]);
> +
> return -ENOMEM;
> }
>
> cmp = vmalloc(LZO_CMP_SIZE);
> if (!cmp) {
> printk(KERN_ERR "PM: Failed to allocate LZO compressed\n");
> +
> vfree(unc);
> - free_page((unsigned long)page);
> + for (i = 0; i < LZO_CMP_PAGES; i++)
> + free_page((unsigned long)page[i]);
> +
> return -ENOMEM;
> }
>
> @@ -787,6 +801,7 @@ static int load_image_lzo(struct swap_map_handle
> *handle,
> if (!m)
> m = 1;
> nr_pages = 0;
> + bio = NULL;
> do_gettimeofday(&start);
>
> error = snapshot_write_next(snapshot);
> @@ -794,11 +809,11 @@ static int load_image_lzo(struct swap_map_handle
> *handle,
> goto out_finish;
>
> for (;;) {
> - error = swap_read_page(handle, page, NULL); /* sync */
> + error = swap_read_page(handle, page[0], NULL); /* sync */
> if (error)
> break;
>
> - cmp_len = *(size_t *)page;
> + cmp_len = *(size_t *)page[0];
> if (unlikely(!cmp_len ||
> cmp_len > lzo1x_worst_compress(LZO_UNC_SIZE))) {
> printk(KERN_ERR "PM: Invalid LZO compressed length\n");
> @@ -806,13 +821,20 @@ static int load_image_lzo(struct swap_map_handle
> *handle,
> break;
> }
>
> - memcpy(cmp, page, PAGE_SIZE);
> - for (off = PAGE_SIZE; off < LZO_HEADER + cmp_len; off += PAGE_SIZE) {
> - error = swap_read_page(handle, page, NULL); /* sync */
> + for (off = PAGE_SIZE, i = 1;
> + off < LZO_HEADER + cmp_len; off += PAGE_SIZE, i++) {
> + error = swap_read_page(handle, page[i], &bio);
> if (error)
> goto out_finish;
> + }
>
> - memcpy(cmp + off, page, PAGE_SIZE);
> + error = hib_wait_on_bio_chain(&bio); /* need all data now */
> + if (error)
> + goto out_finish;
> +
> + for (off = 0, i = 0;
> + off < LZO_HEADER + cmp_len; off += PAGE_SIZE, i++) {
> + memcpy(cmp + off, page[i], PAGE_SIZE);
> }
>
> unc_len = LZO_UNC_SIZE;
> @@ -857,7 +879,8 @@ out_finish:
>
> vfree(cmp);
> vfree(unc);
> - free_page((unsigned long)page);
> + for (i = 0; i < LZO_CMP_PAGES; i++)
> + free_page((unsigned long)page[i]);
>
> return error;
> }
>
>
>
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