>From 6fa7e053c9b37ffd3e329785bb37b96e4185f155 Mon Sep 17 00:00:00 2001
From: Nigel Cunningham <nigel@xxxxxxxxxxxx>
Date: Mon, 6 Jul 2009 14:05:39 +1000
Subject: [PATCH] Hibernation: Add compression support.
Add support for compressing pages using the LZO cryptoapi algorithm.
Since this algorithm usually achieves approximately 60% compression,
allow ourselves to overcommit the available swap a little - assume
compression of at least 40% will be achieved when deciding if we
have enough swapspace available.
Signed-off-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
---
kernel/power/Kconfig | 16 ++++++
kernel/power/Makefile | 1 +
kernel/power/compress.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++
kernel/power/hibernate.c | 12 ++++
kernel/power/power.h | 27 ++++++++++
kernel/power/swap.c | 10 +++-
6 files changed, 189 insertions(+), 2 deletions(-)
create mode 100644 kernel/power/compress.c
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 72067cb..041e266 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -183,6 +183,22 @@ config PM_STD_PARTITION
suspended image to. It will simply pick the first available swap
device.
+config HIBERNATION_COMPRESSION
+ bool "Compression support"
+ depends on HIBERNATION && CRYPTO
+ select CRYPTO_LZO
+ default y
+ ---help---
+ This option adds support for using cryptoapi LZO compression
+ algorithm. Compression is particularly useful as it can
+ more than double your hibernation speed (depending
+ upon how well your image compresses).
+
+ You probably want this, so say Y here.
+
+comment "No compression support available without Cryptoapi support."
+ depends on HIBERNATION && !CRYPTO
+
config APM_EMULATION
tristate "Advanced Power Management Emulation"
depends on PM && SYS_SUPPORTS_APM_EMULATION
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index c3b81c3..c341a8e 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -10,5 +10,6 @@ obj-$(CONFIG_SUSPEND) += suspend.o
obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o
obj-$(CONFIG_HIBERNATION) += swsusp.o hibernate.o snapshot.o swap.o user.o
obj-$(CONFIG_HIBERNATION_NVS) += hibernate_nvs.o
+obj-${CONFIG_HIBERNATION_COMPRESSION} += compress.o
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff --git a/kernel/power/compress.c b/kernel/power/compress.c
new file mode 100644
index 0000000..bb508e2
--- /dev/null
+++ b/kernel/power/compress.c
@@ -0,0 +1,125 @@
+/*
+ * kernel/power/compression.c
+ *
+ * Copyright (C) 2003-2009 Nigel Cunningham (nigel at tuxonice net)
+ *
+ * This file is released under the GPLv2.
+ *
+ * This file contains data compression routines for hibernation,
+ * using cryptoapi.
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/crypto.h>
+
+static const char hibernate_compressor_name[32] = "lzo";
+
+static struct crypto_comp *transform;
+static unsigned int len;
+static char *output_buffer;
+
+/*
+ * hibernate_compress_cleanup
+ *
+ * Frees memory allocated for our labours.
+ */
+void hibernate_compress_cleanup(void)
+{
+ if (transform) {
+ crypto_free_comp(transform);
+ transform = NULL;
+ }
+
+ if (output_buffer) {
+ vfree(output_buffer);
+ output_buffer = NULL;
+ }
+}
+
+/*
+ * hibernate_crypto_prepare
+ *
+ * Prepare to do some work by allocating buffers and transforms.
+ */
+int hibernate_compress_prepare(void)
+{
+ transform = crypto_alloc_comp(hibernate_compressor_name, 0, 0);
+ if (IS_ERR(transform)) {
+ printk(KERN_INFO "Hibernation: Failed to initialise the "
+ "%s compression transform.\n",
+ hibernate_compressor_name);
+ transform = NULL;
+ return 1;
+ }
+
+ output_buffer = (char *) vmalloc_32(2 * PAGE_SIZE);
+
+ if (!output_buffer) {
+ printk(KERN_ERR "Failed to allocate a output buffer for "
+ "hibernation compression support.\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+
+/*
+ * hibernate_compress_write_page()
+ *
+ * Compress a page of data, buffering output and passing on filled
+ * pages to the next module in the pipeline.
+ *
+ * Buffer_page: Pointer to a buffer of size PAGE_SIZE, containing
+ * data to be compressed.
+ *
+ * Returns: 0 on success. Otherwise the error is that returned by later
+ * modules, -ECHILD if we have a broken pipeline or -EIO if
+ * zlib errs.
+ */
+int hibernate_compress_page(void *buffer_page)
+{
+ int ret;
+
+ len = PAGE_SIZE;
+
+ ret = crypto_comp_compress(transform, buffer_page, PAGE_SIZE,
+ output_buffer, &len);
+
+ if (!ret && len < PAGE_SIZE) { /* some compression */
+ memcpy(buffer_page, output_buffer, len);
+ return len;
+ } else
+ return PAGE_SIZE;
+}
+
+/*
+ * hibernate_compress_read_page()
+ * @buffer_page: struct page *. Pointer to a buffer of size PAGE_SIZE.
+ *
+ * Retrieve data from later modules and decompress it until the input buffer
+ * is filled.
+ * Zero if successful. Error condition from me or from downstream on failure.
+ */
+int hibernate_decompress_page(char *buffer_start, unsigned int len)
+{
+ unsigned int outlen = PAGE_SIZE;
+ int ret;
+
+ /* Error or uncompressed data */
+ if (len == PAGE_SIZE)
+ return 0;
+
+ memcpy(output_buffer, buffer_start, len);
+ ret = crypto_comp_decompress(transform, output_buffer, len, buffer_start,
+ &outlen);
+ if (ret)
+ printk(KERN_ERR "Hibernation: Decompression returned %d.\n",
+ ret);
+ else if (outlen != PAGE_SIZE) {
+ printk(KERN_ERR "Decompression yielded %d bytes instead of "
+ "%ld.\n", outlen, PAGE_SIZE);
+ ret = -EIO;
+ }
+ return ret;
+}
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 81d2e74..238266d 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -550,6 +550,11 @@ int hibernate(void)
}
pm_prepare_console();
+
+ error = hibernate_compress_prepare();
+ if (error)
+ goto Exit;
+
error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
if (error)
goto Exit;
@@ -599,6 +604,7 @@ int hibernate(void)
usermodehelper_enable();
Exit:
pm_notifier_call_chain(PM_POST_HIBERNATION);
+ hibernate_compress_cleanup();
pm_restore_console();
atomic_inc(&snapshot_device_available);
Unlock:
@@ -690,6 +696,11 @@ static int software_resume(void)
}
pm_prepare_console();
+
+ error = hibernate_compress_prepare();
+ if (error)
+ goto Finish;
+
error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
if (error)
goto Finish;
@@ -723,6 +734,7 @@ static int software_resume(void)
usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);
+ hibernate_compress_cleanup();
pm_restore_console();
atomic_inc(&snapshot_device_available);
/* For success case, the suspend path will release the lock */
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 26d5a26..5e7813f 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -49,6 +49,33 @@ static inline char *check_image_kernel(struct swsusp_info *info)
extern int hibernation_snapshot(int platform_mode);
extern int hibernation_restore(int platform_mode);
extern int hibernation_platform_enter(void);
+
+#ifdef CONFIG_HIBERNATION_COMPRESSION
+void hibernate_compress_cleanup(void);
+int hibernate_compress_prepare(void);
+int hibernate_compress_page(char *page);
+int hibernate_decompress_page(char *page, int size);
+#else
+static void hibernate_compress_cleanup(void)
+{
+}
+
+static int hibernate_compress_prepare(void)
+{
+ return 0;
+}
+
+static int hibernate_compress_page(void *buffer)
+{
+ return PAGE_SIZE;
+}
+
+static int hibernate_decompress_page(void *buffer, int size)
+{
+ return PAGE_SIZE;
+}
+
+#endif
#endif
extern int pfn_is_nosave(unsigned long);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 260c622..22aa4d3 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -393,7 +393,7 @@ static int save_image(struct swap_map_handle *handle,
do {
ret = snapshot_read_next(snapshot, PAGE_SIZE);
if (ret > 0) {
- int bytes = PAGE_SIZE;
+ int bytes = hibernate_compress_page(data_of(*snapshot));
/*
* Write the size of the (possibly) compressed data and
@@ -430,6 +430,8 @@ static int save_image(struct swap_map_handle *handle,
*
* Returns TRUE or FALSE after checking the total amount of swap
* space avaiable from the resume partition.
+ *
+ * Assumes compression of at least 40% will be achieved.
*/
static int enough_swap(unsigned int nr_pages)
@@ -437,7 +439,7 @@ 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) * 1.01;
+ return free_swap > (nr_pages + PAGES_FOR_IO) * .6;
}
/**
@@ -608,8 +610,12 @@ static int load_image(struct swap_map_handle *handle,
handle, &bio);
if (error)
break;
+
if (snapshot->sync_read)
error = wait_on_bio_chain(&bio);
+
+ error = hibernate_decompress_page(data_of(*snapshot), bytes);
+
if (error)
break;
if (!(nr_pages % m))
--
1.6.0.4
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