From f8262d476823a7ea1eb497ff9676d1eab2393c75 Mon Sep 17 00:00:00 2001 From: Bojan Smojver Date: Tue, 24 Apr 2012 23:53:28 +0200 Subject: 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 081a9d043c983f161b78fdc4671324d1342b86bc 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: Bojan Smojver Signed-off-by: Rafael J. Wysocki --- kernel/power/swap.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 8742fd013a9..eef311a58a6 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -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. -- cgit v1.2.3