[PATCH 3.4 20/24] PM / Hibernate: Hibernate/thaw fixes/improvements

Greg Kroah-Hartman
2014-02-18T22:46:13Z

From: Bojan Smojver <bojan@rexursive.com>

commit 5a21d489fd9541a4a66b9a500659abaca1b19a51 upstream.

1. Do not allocate memory for buffers from emergency pools, unless
absolutely required. Do not warn about and do not retry non-essential
failed allocations.

2. Do not check the amount of free pages left on every single page
write, but wait until one map is completely populated and then check.

3. Set maximum number of pages for read buffering consistently, instead
of inadvertently depending on the size of the sector type.

4. Fix copyright line, which I missed when I submitted the hibernation
threading patch.

5. Dispense with bit shifting arithmetic to improve readability.

6. Really recalculate the number of pages required to be free after all
allocations have been done.

7. Fix calculation of pages required for read buffering. Only count in
pages that do not belong to high memory.

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/power/swap.c | 62 ++++++++++++++++++++++++++++++++--------------------
1 file changed, 39 insertions(+), 23 deletions(-)

--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -6,7 +6,7 @@
*
* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
- * Copyright (C) 2010 Bojan Smojver <bojan@rexursive.com>
+ * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
*
* This file is released under the GPLv2.
*
@@ -282,14 +282,17 @@ static int write_page(void *buf, sector_
return -ENOSPC;

if (bio_chain) {
- src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+ src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
+ __GFP_NORETRY);
if (src) {
copy_page(src, buf);
} else {
ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
if (ret)
return ret;
- src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+ src = (void *)__get_free_page(__GFP_WAIT |
+ __GFP_NOWARN |
+ __GFP_NORETRY);
if (src) {
copy_page(src, buf);
} else {
@@ -367,12 +370,17 @@ static int swap_write_page(struct swap_m
clear_page(handle->cur);
handle->cur_swap = offset;
handle->k = 0;
- }
- if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
- error = hib_wait_on_bio_chain(bio_chain);
- if (error)
- goto out;
- handle->reqd_free_pages = reqd_free_pages();
+
+ if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
+ error = hib_wait_on_bio_chain(bio_chain);
+ if (error)
+ goto out;
+ /*
+ * Recalculate the number of required free pages, to
+ * make sure we never take more than half.
+ */
+ handle->reqd_free_pages = reqd_free_pages();
+ }
}
out:
return error;
@@ -419,8 +427,9 @@ static int swap_writer_finish(struct swa
/* Maximum number of threads for compression/decompression. */
#define LZO_THREADS 3

-/* Maximum number of pages for read buffering. */
-#define LZO_READ_PAGES (MAP_PAGE_ENTRIES * 8)
+/* Minimum/maximum number of pages for read buffering. */
+#define LZO_MIN_RD_PAGES 1024
+#define LZO_MAX_RD_PAGES 8192

/**
@@ -631,12 +640,6 @@ static int save_image_lzo(struct swap_ma
}

/*
- * Adjust number of free pages after all allocations have been done.
- * We don't want to run out of pages when writing.
- */
- handle->reqd_free_pages = reqd_free_pages();
-
- /*
* Start the CRC32 thread.
*/
init_waitqueue_head(&crc->go);
@@ -657,6 +660,12 @@ static int save_image_lzo(struct swap_ma
goto out_clean;
}

+ /*
+ * Adjust the number of required free pages after all allocations have
+ * been done. We don't want to run out of pages when writing.
+ */
+ handle->reqd_free_pages = reqd_free_pages();
+
printk(KERN_INFO
"PM: Using %u thread(s) for compression.\n"
"PM: Compressing and saving image data (%u pages) ... ",
@@ -1067,7 +1076,7 @@ static int load_image_lzo(struct swap_ma
unsigned i, thr, run_threads, nr_threads;
unsigned ring = 0, pg = 0, ring_size = 0,
have = 0, want, need, asked = 0;
- unsigned long read_pages;
+ unsigned long read_pages = 0;
unsigned char **page = NULL;
struct dec_data *data = NULL;
struct crc_data *crc = NULL;
@@ -1079,7 +1088,7 @@ static int load_image_lzo(struct swap_ma
nr_threads = num_online_cpus() - 1;
nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);

- page = vmalloc(sizeof(*page) * LZO_READ_PAGES);
+ page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
if (!page) {
printk(KERN_ERR "PM: Failed to allocate LZO page\n");
ret = -ENOMEM;
@@ -1144,15 +1153,22 @@ static int load_image_lzo(struct swap_ma
}

/*
- * Adjust number of pages for read buffering, in case we are short.
+ * Set the number of pages for read buffering.
+ * This is complete guesswork, because we'll only know the real
+ * picture once prepare_image() is called, which is much later on
+ * during the image load phase. We'll assume the worst case and
+ * say that none of the image pages are from high memory.
*/
- read_pages = (nr_free_pages() - snapshot_get_image_size()) >> 1;
- read_pages = clamp_val(read_pages, LZO_CMP_PAGES, LZO_READ_PAGES);
+ if (low_free_pages() > snapshot_get_image_size())
+ read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
+ read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);

for (i = 0; i < read_pages; i++) {
page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
__GFP_WAIT | __GFP_HIGH :
- __GFP_WAIT);
+ __GFP_WAIT | __GFP_NOWARN |
+ __GFP_NORETRY);
+
if (!page[i]) {
if (i < LZO_CMP_PAGES) {
ring_size = i;