Commit f8262d47 authored by Bojan Smojver's avatar Bojan Smojver Committed by Rafael J. Wysocki
Browse files

PM / Hibernate: fix the number of pages used for hibernate/thaw buffering 



Hibernation regression fix, since 3.2.

Calculate the number of required free pages based on non-high memory
pages only, because that is where the buffers will come from.

Commit 081a9d04 introduced a new buffer
page allocation logic during hibernation, in order to improve the
performance. The amount of pages allocated was calculated based on total
amount of pages available, although only non-high memory pages are
usable for this purpose. This caused hibernation code to attempt to over
allocate pages on platforms that have high memory, which led to hangs.

Signed-off-by: default avatarBojan Smojver <bojan@rexursive.com>
Signed-off-by: default avatarRafael J. Wysocki <rjw@suse.de>
parent 66f75a5d

kernel/power/swap.c

+22 −6
Original line number Diff line number Diff line
@@ -51,6 +51,23 @@ 


#define MAP_PAGE_ENTRIES	(PAGE_SIZE / sizeof(sector_t) - 1)



/*

 * Number of free pages that are not high.

 */

static inline unsigned long low_free_pages(void)

{

	return nr_free_pages() - nr_free_highpages();

}



/*

 * Number of pages required to be kept free while writing the image. Always

 * half of all available low pages before the writing starts.

 */

static inline unsigned long reqd_free_pages(void)

{

	return low_free_pages() / 2;

}



struct swap_map_page {

	sector_t entries[MAP_PAGE_ENTRIES];

	sector_t next_swap;
@@ -72,7 +89,7 @@ struct swap_map_handle { 
	sector_t cur_swap;

	sector_t first_sector;

	unsigned int k;

	unsigned long nr_free_pages, written;

	unsigned long reqd_free_pages;

	u32 crc32;

};
@@ -316,8 +333,7 @@ static int get_swap_writer(struct swap_map_handle *handle) 
		goto err_rel;

	}

	handle->k = 0;

	handle->nr_free_pages = nr_free_pages() >> 1;

	handle->written = 0;

	handle->reqd_free_pages = reqd_free_pages();

	handle->first_sector = handle->cur_swap;

	return 0;

err_rel:
@@ -352,11 +368,11 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf, 
		handle->cur_swap = offset;

		handle->k = 0;

	}

	if (bio_chain && ++handle->written > handle->nr_free_pages) {

	if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {

		error = hib_wait_on_bio_chain(bio_chain);

		if (error)

			goto out;

		handle->written = 0;

		handle->reqd_free_pages = reqd_free_pages();

	}

 out:

	return error;
@@ -618,7 +634,7 @@ static int save_image_lzo(struct swap_map_handle *handle, 
	 * Adjust number of free pages after all allocations have been done.

	 * We don't want to run out of pages when writing.

	 */

	handle->nr_free_pages = nr_free_pages() >> 1;

	handle->reqd_free_pages = reqd_free_pages();



	/*

	 * Start the CRC32 thread.

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