lkml.org 
[lkml]   [2012]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH v11]: Hibernation: fix the number of pages used for hibernate/thaw buffering
From
Date
On Mon, 2012-04-23 at 23:59 +0200, Rafael J. Wysocki wrote:
> Please resend it with a better changelog. I mean, please explain what
> the regression is and why it is being fixed this way.

---------------------------------------
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.

A more elaborate patch, which also addressed other hibernation/thaw
issues, has been merged into linux-next, commit
e9cbc5a6270be7aa9c42d9b15293ba9ac7161262.

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
---
kernel/power/swap.c | 33 +++++++++++++++++++++++++--------
1 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 8742fd0..fdf834f 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.
---------------------------------------
--
Bojan



\
 
 \ /
  Last update: 2012-04-24 00:43    [W:0.117 / U:1.188 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site