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Date: Wed, 04 Aug 2010 12:42:56 +1000
From: Nigel Cunningham <nigel@...onice.net>
To: Bojan Smojver <bojan@...ursive.com>
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH]: Compress hibernation image with LZO (in-kernel)
Hi again.
On 03/08/10 12:30, Bojan Smojver wrote:
> On Tue, 2010-08-03 at 11:59 +1000, Bojan Smojver wrote:
>> PS. I also enhanced the patch to use overlapping compression in order
>> to save memory. Looks like that's causing it to be slower on
>> compression (we go down from 130 - 150 MB/s to around 105 - 110 MB/s),
>> but still over 3 times faster than regular swsusp code. Decompression
>> remains roughly the same around 100+ MB/s (this is double the speed of
>> current swsusp code). I will post this a bit later on.
>
> As promised.
Round here, people generally like to see improvements split up into
small patches that change just one thing. I'd therefore suggest
splitting the removal of sync_read from the rest of the patch. Is it
standalone? I'm not seeing the relationship between the two parts at the
moment.
> diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
> index ca6066a..cb57eb9 100644
> --- a/kernel/power/Kconfig
> +++ b/kernel/power/Kconfig
> @@ -137,6 +137,8 @@ config SUSPEND_FREEZER
> config HIBERNATION
> bool "Hibernation (aka 'suspend to disk')"
> depends on PM&& SWAP&& ARCH_HIBERNATION_POSSIBLE
> + select LZO_COMPRESS
> + select LZO_DECOMPRESS
> select SUSPEND_NVS if HAS_IOMEM
> ---help---
> Enable the suspend to disk (STD) functionality, which is usually
> diff --git a/kernel/power/power.h b/kernel/power/power.h
> index 006270f..a760cf8 100644
> --- a/kernel/power/power.h
> +++ b/kernel/power/power.h
> @@ -103,10 +103,6 @@ struct snapshot_handle {
> void *buffer; /* address of the block to read from
> * or write to
> */
> - int sync_read; /* Set to one to notify the caller of
> - * snapshot_write_next() that it may
> - * need to call wait_on_bio_chain()
> - */
> };
>
> /* This macro returns the address from/to which the caller of
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index 25ce010..f24ee24 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -2135,8 +2135,6 @@ int snapshot_write_next(struct snapshot_handle *handle)
> if (handle->cur> 1&& handle->cur> nr_meta_pages + nr_copy_pages)
> return 0;
>
> - handle->sync_read = 1;
> -
> if (!handle->cur) {
> if (!buffer)
> /* This makes the buffer be freed by swsusp_free() */
> @@ -2169,7 +2167,6 @@ int snapshot_write_next(struct snapshot_handle *handle)
> memory_bm_position_reset(&orig_bm);
> restore_pblist = NULL;
> handle->buffer = get_buffer(&orig_bm,&ca);
> - handle->sync_read = 0;
> if (IS_ERR(handle->buffer))
> return PTR_ERR(handle->buffer);
> }
> @@ -2178,8 +2175,6 @@ int snapshot_write_next(struct snapshot_handle *handle)
> handle->buffer = get_buffer(&orig_bm,&ca);
> if (IS_ERR(handle->buffer))
> return PTR_ERR(handle->buffer);
> - if (handle->buffer != buffer)
> - handle->sync_read = 0;
> }
> handle->cur++;
> return PAGE_SIZE;
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index b0bb217..5a83fd3 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -24,6 +24,7 @@
> #include<linux/swapops.h>
> #include<linux/pm.h>
> #include<linux/slab.h>
> +#include<linux/lzo.h>
>
> #include "power.h"
>
> @@ -357,6 +358,18 @@ static int swap_writer_finish(struct swap_map_handle *handle,
> return error;
> }
>
> +#define LZO_HEADER sizeof(size_t)
> +#define LZO_UNC_PAGES 64
> +#define LZO_UNC_SIZE (LZO_UNC_PAGES * PAGE_SIZE)
> +#define LZO_CMP_PAGES DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
> + LZO_HEADER, PAGE_SIZE)
> +#define LZO_CMP_SIZE (LZO_CMP_PAGES * PAGE_SIZE)
> +#define LZO_OVH_PAGES DIV_ROUND_UP((LZO_UNC_SIZE > 0xBFFF ? \
> + 0xBFFF : LZO_UNC_SIZE) + \
> + LZO_UNC_SIZE / 16 + 64 + 3 + \
> + LZO_HEADER, PAGE_SIZE)
> +#define LZO_OVH_SIZE (LZO_OVH_PAGES + PAGE_SIZE)
> +
Some commenting for these #defines would be good, especially the 'magic'
numbers 0xBFF, 16, 64 and 3. It's all a bit unreadable, too :) Maybe
something like (untested...):
#define LZO_HEADER sizeof(size_t)
#define LZO_UNC_PAGES 64
#define LZO_UNC_SIZE (LZO_UNC_PAGES * PAGE_SIZE)
#define LZO_CMP_PAGES \
DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + LZO_HEADER,
PAGE_SIZE)
#define LZO_CMP_SIZE (LZO_CMP_PAGES * PAGE_SIZE)
#define LZO_MAGIC_1 0xBFFF /* Rename to whatever this is */
#define LZO_MAGIC_2 16 /* Rename */
#define LZO_MAGIC_3 (64 + 3) /* Rename */
#define LZO_OVH_PAGES
DIV_ROUND_UP(min(LZO_UNC_SIZE, LZO_MAGIC_1) + \
LZO_UNC_SIZE / LZO_MAGIC2 + \
LZO_MAGIC_3 + \
LZO_HEADER,
PAGE_SIZE)
#define LZO_OVH_SIZE (LZO_OVH_PAGES + PAGE_SIZE)
> /**
> * save_image - save the suspend image data
> */
> @@ -372,6 +385,29 @@ static int save_image(struct swap_map_handle *handle,
> struct bio *bio;
> struct timeval start;
> struct timeval stop;
> + size_t ul, cl;
rename to bytes_in and bytes_out? I can guess they mean
uncompressed/compressed length, but it's a little cryptic.
> + unsigned char *buf, *wrk, *page;
> +
> + page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
> + if (!page) {
> + printk(KERN_ERR "PM: Failed to allocate LZO page\n");
> + return -ENOMEM;
> + }
> +
> + wrk = vmalloc(LZO1X_1_MEM_COMPRESS);
> + if (!wrk) {
> + printk(KERN_ERR "PM: Failed to allocate LZO workspace\n");
> + free_page((unsigned long)page);
> + return -ENOMEM;
> + }
> +
> + buf = vmalloc(LZO_UNC_SIZE + LZO_OVH_SIZE);
> + if (!buf) {
> + printk(KERN_ERR "PM: Failed to allocate LZO buffer\n");
> + vfree(wrk);
> + free_page((unsigned long)page);
> + return -ENOMEM;
> + }
>
> printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ",
> nr_to_write);
> @@ -382,16 +418,50 @@ static int save_image(struct swap_map_handle *handle,
> bio = NULL;
> do_gettimeofday(&start);
> while (1) {
> - ret = snapshot_read_next(snapshot);
> - if (ret<= 0)
> + for (ul = 0; ul< LZO_UNC_SIZE; ul += PAGE_SIZE) {
> + ret = snapshot_read_next(snapshot);
> + if (ret< 0)
Not sure why my email client (Thunderbird) is shifting your comparison
operators :(
> + goto out_finish;
> +
> + if (ret == 0)
if (!ret)
(Further down, too)
> + break;
> +
> + memcpy(buf + LZO_OVH_SIZE + ul,
> + data_of(*snapshot), PAGE_SIZE);
> +
> + if (!(nr_pages % m))
> + printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
> + nr_pages++;
> + }
> +
> + if (ul == 0)
> + break;
> +
> + ret = lzo1x_1_compress(buf + LZO_OVH_SIZE, ul,
> + buf + LZO_HEADER,&cl, wrk);
> + if (ret< 0) {
> + printk(KERN_ERR "PM: LZO compression failed\n");
> break;
> - ret = swap_write_page(handle, data_of(*snapshot),&bio);
> - if (ret)
> + }
> +
> + if (unlikely(cl == 0 || LZO_HEADER + cl> LZO_CMP_SIZE)) {
> + printk(KERN_ERR "PM: Invalid LZO length\n");
> + ret = -1;
> break;
> - if (!(nr_pages % m))
> - printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
> - nr_pages++;
> + }
> +
> + *(size_t *)buf = cl;
> +
> + for (ul = 0; ul< LZO_HEADER + cl; ul += PAGE_SIZE) {
> + memcpy(page, buf + ul, PAGE_SIZE);
> +
> + ret = swap_write_page(handle, page,&bio);
> + if (ret)
> + goto out_finish;
> + }
> }
> +
> +out_finish:
> err2 = hib_wait_on_bio_chain(&bio);
> do_gettimeofday(&stop);
> if (!ret)
> @@ -401,6 +471,11 @@ static int save_image(struct swap_map_handle *handle,
> else
> printk(KERN_CONT "\n");
> swsusp_show_speed(&start,&stop, nr_to_write, "Wrote");
> +
> + vfree(buf);
> + vfree(wrk);
> + free_page((unsigned long)page);
> +
> return ret;
> }
>
> @@ -416,7 +491,8 @@ static int enough_swap(unsigned int nr_pages)
> unsigned int free_swap = count_swap_pages(root_swap, 1);
>
> pr_debug("PM: Free swap pages: %u\n", free_swap);
> - return free_swap> nr_pages + PAGES_FOR_IO;
> + return free_swap>
> + (nr_pages * LZO_CMP_PAGES) / LZO_UNC_PAGES + 1 + PAGES_FOR_IO;
PAGES_FOR_IO doesn't belong here, but that's not your problem :)
> }
>
> /**
> @@ -547,9 +623,22 @@ static int load_image(struct swap_map_handle *handle,
> int error = 0;
> struct timeval start;
> struct timeval stop;
> - struct bio *bio;
> - int err2;
> unsigned nr_pages;
> + size_t ul, cl, off;
As per comments on ul and cl above.
[...]
Regards,
Nigel
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