* [PATCH 2/5] jffs2: Add LZO compression support to jffs2
@ 2007-02-28 19:13 Richard Purdie
2007-04-25 12:35 ` David Woodhouse
0 siblings, 1 reply; 6+ messages in thread
From: Richard Purdie @ 2007-02-28 19:13 UTC (permalink / raw)
To: LKML, David Woodhouse, herbert; +Cc: linux-mtd, linux-crypto
Add LZO1X compression/decompression support to jffs2.
LZO's interface doesn't entirely match that required by jffs2 so a
buffer and memcpy is unavoidable.
Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
---
fs/Kconfig | 10 ++++
fs/jffs2/Makefile | 1
fs/jffs2/compr.c | 6 ++
fs/jffs2/compr.h | 3 -
fs/jffs2/compr_lzo.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/jffs2.h | 1
6 files changed, 140 insertions(+), 1 deletion(-)
Index: linux/fs/Kconfig
===================================================================
--- linux.orig/fs/Kconfig 2007-02-28 18:12:17.000000000 +0000
+++ linux/fs/Kconfig 2007-02-28 18:13:10.000000000 +0000
@@ -1310,6 +1310,16 @@ config JFFS2_ZLIB
Say 'Y' if unsure.
+config JFFS2_LZO
+ bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
+ select LZO
+ depends on JFFS2_FS
+ default y
+ help
+ minilzo-based compression. Generally works better than Zlib.
+
+ Say 'Y' if unsure.
+
config JFFS2_RTIME
bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
depends on JFFS2_FS
Index: linux/fs/jffs2/Makefile
===================================================================
--- linux.orig/fs/jffs2/Makefile 2007-02-28 18:12:17.000000000 +0000
+++ linux/fs/jffs2/Makefile 2007-02-28 18:12:31.000000000 +0000
@@ -18,4 +18,5 @@ jffs2-$(CONFIG_JFFS2_FS_POSIX_ACL) += ac
jffs2-$(CONFIG_JFFS2_RUBIN) += compr_rubin.o
jffs2-$(CONFIG_JFFS2_RTIME) += compr_rtime.o
jffs2-$(CONFIG_JFFS2_ZLIB) += compr_zlib.o
+jffs2-$(CONFIG_JFFS2_LZO) += compr_lzo.o
jffs2-$(CONFIG_JFFS2_SUMMARY) += summary.o
Index: linux/fs/jffs2/compr.c
===================================================================
--- linux.orig/fs/jffs2/compr.c 2007-02-28 18:12:17.000000000 +0000
+++ linux/fs/jffs2/compr.c 2007-02-28 18:13:10.000000000 +0000
@@ -425,6 +425,9 @@ int __init jffs2_compressors_init(void)
jffs2_rubinmips_init();
jffs2_dynrubin_init();
#endif
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_init();
+#endif
/* Setting default compression mode */
#ifdef CONFIG_JFFS2_CMODE_NONE
jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
@@ -443,6 +446,9 @@ int __init jffs2_compressors_init(void)
int jffs2_compressors_exit(void)
{
/* Unregistering compressors */
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_exit();
+#endif
#ifdef CONFIG_JFFS2_RUBIN
jffs2_dynrubin_exit();
jffs2_rubinmips_exit();
Index: linux/fs/jffs2/compr_lzo.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux/fs/jffs2/compr_lzo.c 2007-02-28 18:12:31.000000000 +0000
@@ -0,0 +1,120 @@
+/*
+ * JFFS2 LZO Compression Interface
+ *
+ * Copyright (C) 2007 Nokia Corporation. All rights reserved.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/lzo.h>
+#include "compr.h"
+
+static void *lzo_mem;
+static void *lzo_compress_buf;
+static DEFINE_MUTEX(deflate_mutex);
+
+static void free_workspace(void)
+{
+ vfree(lzo_mem);
+ vfree(lzo_compress_buf);
+}
+
+static int __init alloc_workspace(void)
+{
+ lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
+ lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
+
+ if (!lzo_mem || !lzo_compress_buf) {
+ printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
+ free_workspace();
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
+ uint32_t *sourcelen, uint32_t *dstlen, void *model)
+{
+ unsigned long compress_size;
+ int ret;
+
+ mutex_lock(&deflate_mutex);
+ ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
+ mutex_unlock(&deflate_mutex);
+
+ if (ret != LZO_E_OK)
+ return -1;
+
+ if (compress_size > *dstlen)
+ return -1;
+
+ memcpy(cpage_out, lzo_compress_buf, compress_size);
+ *dstlen = compress_size;
+
+ return 0;
+}
+
+static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
+ uint32_t srclen, uint32_t destlen, void *model)
+{
+ unsigned long dl = destlen;
+ int ret;
+
+ ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl, NULL);
+
+ if (ret != LZO_E_OK || dl != destlen)
+ return -1;
+
+ return 0;
+}
+
+static struct jffs2_compressor jffs2_lzo_comp = {
+ .priority = JFFS2_LZO_PRIORITY,
+ .name = "lzo",
+ .compr = JFFS2_COMPR_LZO,
+ .compress = &jffs2_lzo_compress,
+ .decompress = &jffs2_lzo_decompress,
+ .disabled = 0,
+};
+
+int __init jffs2_lzo_init(void)
+{
+ int ret;
+
+ ret = alloc_workspace();
+ if (ret < 0)
+ return ret;
+
+ ret = jffs2_register_compressor(&jffs2_lzo_comp);
+ if (ret)
+ free_workspace();
+
+ return ret;
+}
+
+void jffs2_lzo_exit(void)
+{
+ jffs2_unregister_compressor(&jffs2_lzo_comp);
+ free_workspace();
+}
Index: linux/include/linux/jffs2.h
===================================================================
--- linux.orig/include/linux/jffs2.h 2007-02-28 18:12:17.000000000 +0000
+++ linux/include/linux/jffs2.h 2007-02-28 18:12:31.000000000 +0000
@@ -46,6 +46,7 @@
#define JFFS2_COMPR_COPY 0x04
#define JFFS2_COMPR_DYNRUBIN 0x05
#define JFFS2_COMPR_ZLIB 0x06
+#define JFFS2_COMPR_LZO 0x07
/* Compatibility flags. */
#define JFFS2_COMPAT_MASK 0xc000 /* What do to if an unknown nodetype is found */
#define JFFS2_NODE_ACCURATE 0x2000
Index: linux/fs/jffs2/compr.h
===================================================================
--- linux.orig/fs/jffs2/compr.h 2007-02-28 18:12:17.000000000 +0000
+++ linux/fs/jffs2/compr.h 2007-02-28 18:13:10.000000000 +0000
@@ -30,9 +30,10 @@
#define JFFS2_RUBINMIPS_PRIORITY 10
#define JFFS2_DYNRUBIN_PRIORITY 20
#define JFFS2_LZARI_PRIORITY 30
-#define JFFS2_LZO_PRIORITY 40
#define JFFS2_RTIME_PRIORITY 50
#define JFFS2_ZLIB_PRIORITY 60
+#define JFFS2_LZO_PRIORITY 80
+
#define JFFS2_RUBINMIPS_DISABLED /* RUBINs will be used only */
#define JFFS2_DYNRUBIN_DISABLED /* for decompression */
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/5] jffs2: Add LZO compression support to jffs2
2007-02-28 19:13 Richard Purdie
@ 2007-04-25 12:35 ` David Woodhouse
0 siblings, 0 replies; 6+ messages in thread
From: David Woodhouse @ 2007-04-25 12:35 UTC (permalink / raw)
To: Richard Purdie; +Cc: LKML, herbert, linux-mtd, linux-crypto
On Wed, 2007-02-28 at 19:13 +0000, Richard Purdie wrote:
> Add LZO1X compression/decompression support to jffs2.
>
> LZO's interface doesn't entirely match that required by jffs2 so a
> buffer and memcpy is unavoidable.
>
> Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
> Index: linux/fs/jffs2/compr_lzo.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux/fs/jffs2/compr_lzo.c 2007-02-28 18:12:31.000000000 +0000
> @@ -0,0 +1,120 @@
> +/*
> + * JFFS2 LZO Compression Interface
> + *
> + * Copyright (C) 2007 Nokia Corporation. All rights reserved.
> + *
> + * Author: Richard Purdie <rpurdie@openedhand.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> + * 02110-1301 USA
> + *
> + */
Please use the same licence, and the same boilerplate, as the rest of
the JFFS2 code.
--
dwmw2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/5] jffs2: Add LZO compression support to jffs2
@ 2007-05-01 14:47 Richard Purdie
2007-05-01 20:00 ` Randy Dunlap
2007-05-04 9:06 ` Satyam Sharma
0 siblings, 2 replies; 6+ messages in thread
From: Richard Purdie @ 2007-05-01 14:47 UTC (permalink / raw)
To: LKML, David Woodhouse, herbert; +Cc: linux-mtd, linux-crypto
Add LZO1X compression/decompression support to jffs2.
LZO's interface doesn't entirely match that required by jffs2 so a
buffer and memcpy is unavoidable.
Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
---
fs/Kconfig | 10 ++++
fs/jffs2/Makefile | 1 +
fs/jffs2/compr.c | 6 +++
fs/jffs2/compr.h | 7 +++-
fs/jffs2/compr_lzo.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/jffs2.h | 1 +
6 files changed, 134 insertions(+), 1 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig
index a42f767..1645dfa 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1310,6 +1310,16 @@ config JFFS2_ZLIB
Say 'Y' if unsure.
+config JFFS2_LZO
+ bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
+ select LZO
+ depends on JFFS2_FS
+ default y
+ help
+ minilzo-based compression. Generally works better than Zlib.
+
+ Say 'Y' if unsure.
+
config JFFS2_RTIME
bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
depends on JFFS2_FS
diff --git a/fs/jffs2/Makefile b/fs/jffs2/Makefile
index c32b241..60e5d49 100644
--- a/fs/jffs2/Makefile
+++ b/fs/jffs2/Makefile
@@ -17,4 +17,5 @@ jffs2-$(CONFIG_JFFS2_FS_POSIX_ACL) += acl.o
jffs2-$(CONFIG_JFFS2_RUBIN) += compr_rubin.o
jffs2-$(CONFIG_JFFS2_RTIME) += compr_rtime.o
jffs2-$(CONFIG_JFFS2_ZLIB) += compr_zlib.o
+jffs2-$(CONFIG_JFFS2_LZO) += compr_lzo.o
jffs2-$(CONFIG_JFFS2_SUMMARY) += summary.o
diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c
index 485d065..6a23408 100644
--- a/fs/jffs2/compr.c
+++ b/fs/jffs2/compr.c
@@ -285,6 +285,9 @@ int __init jffs2_compressors_init(void)
jffs2_rubinmips_init();
jffs2_dynrubin_init();
#endif
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_init();
+#endif
/* Setting default compression mode */
#ifdef CONFIG_JFFS2_CMODE_NONE
jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
@@ -303,6 +306,9 @@ int __init jffs2_compressors_init(void)
int jffs2_compressors_exit(void)
{
/* Unregistering compressors */
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_exit();
+#endif
#ifdef CONFIG_JFFS2_RUBIN
jffs2_dynrubin_exit();
jffs2_rubinmips_exit();
diff --git a/fs/jffs2/compr.h b/fs/jffs2/compr.h
index 68cc701..8c6b2af 100644
--- a/fs/jffs2/compr.h
+++ b/fs/jffs2/compr.h
@@ -27,9 +27,10 @@
#define JFFS2_RUBINMIPS_PRIORITY 10
#define JFFS2_DYNRUBIN_PRIORITY 20
#define JFFS2_LZARI_PRIORITY 30
-#define JFFS2_LZO_PRIORITY 40
#define JFFS2_RTIME_PRIORITY 50
#define JFFS2_ZLIB_PRIORITY 60
+#define JFFS2_LZO_PRIORITY 80
+
#define JFFS2_RUBINMIPS_DISABLED /* RUBINs will be used only */
#define JFFS2_DYNRUBIN_DISABLED /* for decompression */
@@ -90,5 +91,9 @@ void jffs2_rtime_exit(void);
int jffs2_zlib_init(void);
void jffs2_zlib_exit(void);
#endif
+#ifdef CONFIG_JFFS2_LZO
+int jffs2_lzo_init(void);
+void jffs2_lzo_exit(void);
+#endif
#endif /* __JFFS2_COMPR_H__ */
diff --git a/fs/jffs2/compr_lzo.c b/fs/jffs2/compr_lzo.c
new file mode 100644
index 0000000..6396682
--- /dev/null
+++ b/fs/jffs2/compr_lzo.c
@@ -0,0 +1,110 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * LZO Compression Interface
+ *
+ * Copyright © 2007 Nokia Corporation. All rights reserved.
+ *
+ * Created by Richard Purdie <rpurdie@openedhand.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/lzo.h>
+#include "compr.h"
+
+static void *lzo_mem;
+static void *lzo_compress_buf;
+static DEFINE_MUTEX(deflate_mutex);
+
+static void free_workspace(void)
+{
+ vfree(lzo_mem);
+ vfree(lzo_compress_buf);
+}
+
+static int __init alloc_workspace(void)
+{
+ lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
+ lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
+
+ if (!lzo_mem || !lzo_compress_buf) {
+ printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
+ free_workspace();
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
+ uint32_t *sourcelen, uint32_t *dstlen, void *model)
+{
+ unsigned long compress_size;
+ int ret;
+
+ mutex_lock(&deflate_mutex);
+ ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
+ mutex_unlock(&deflate_mutex);
+
+ if (ret != LZO_E_OK)
+ return -1;
+
+ if (compress_size > *dstlen)
+ return -1;
+
+ memcpy(cpage_out, lzo_compress_buf, compress_size);
+ *dstlen = compress_size;
+
+ return 0;
+}
+
+static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
+ uint32_t srclen, uint32_t destlen, void *model)
+{
+ unsigned long dl = destlen;
+ int ret;
+
+ ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl, NULL);
+
+ if (ret != LZO_E_OK || dl != destlen)
+ return -1;
+
+ return 0;
+}
+
+static struct jffs2_compressor jffs2_lzo_comp = {
+ .priority = JFFS2_LZO_PRIORITY,
+ .name = "lzo",
+ .compr = JFFS2_COMPR_LZO,
+ .compress = &jffs2_lzo_compress,
+ .decompress = &jffs2_lzo_decompress,
+ .disabled = 0,
+};
+
+int __init jffs2_lzo_init(void)
+{
+ int ret;
+
+ ret = alloc_workspace();
+ if (ret < 0)
+ return ret;
+
+ ret = jffs2_register_compressor(&jffs2_lzo_comp);
+ if (ret)
+ free_workspace();
+
+ return ret;
+}
+
+void jffs2_lzo_exit(void)
+{
+ jffs2_unregister_compressor(&jffs2_lzo_comp);
+ free_workspace();
+}
diff --git a/include/linux/jffs2.h b/include/linux/jffs2.h
index 840631f..6b563ca 100644
--- a/include/linux/jffs2.h
+++ b/include/linux/jffs2.h
@@ -46,6 +46,7 @@
#define JFFS2_COMPR_COPY 0x04
#define JFFS2_COMPR_DYNRUBIN 0x05
#define JFFS2_COMPR_ZLIB 0x06
+#define JFFS2_COMPR_LZO 0x07
/* Compatibility flags. */
#define JFFS2_COMPAT_MASK 0xc000 /* What do to if an unknown nodetype is found */
#define JFFS2_NODE_ACCURATE 0x2000
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 2/5] jffs2: Add LZO compression support to jffs2
2007-05-01 14:47 [PATCH 2/5] jffs2: Add LZO compression support to jffs2 Richard Purdie
@ 2007-05-01 20:00 ` Randy Dunlap
2007-05-04 9:06 ` Satyam Sharma
1 sibling, 0 replies; 6+ messages in thread
From: Randy Dunlap @ 2007-05-01 20:00 UTC (permalink / raw)
To: Richard Purdie; +Cc: LKML, David Woodhouse, herbert, linux-mtd, linux-crypto
On Tue, 01 May 2007 15:47:03 +0100 Richard Purdie wrote:
> Add LZO1X compression/decompression support to jffs2.
>
> LZO's interface doesn't entirely match that required by jffs2 so a
> buffer and memcpy is unavoidable.
>
> Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
> ---
>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index a42f767..1645dfa 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -1310,6 +1310,16 @@ config JFFS2_ZLIB
>
> Say 'Y' if unsure.
>
> +config JFFS2_LZO
> + bool "JFFS2 LZO compression support" if JFFS2_COMPRESSION_OPTIONS
> + select LZO
> + depends on JFFS2_FS
> + default y
> + help
> + minilzo-based compression. Generally works better than Zlib.
> +
> + Say 'Y' if unsure.
Use <tab> on the "help" line (instead of spaces) and
use <tab><space><space> on the help text lines.
> config JFFS2_RTIME
> bool "JFFS2 RTIME compression support" if JFFS2_COMPRESSION_OPTIONS
> depends on JFFS2_FS
---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/5] jffs2: Add LZO compression support to jffs2
2007-05-01 14:47 [PATCH 2/5] jffs2: Add LZO compression support to jffs2 Richard Purdie
2007-05-01 20:00 ` Randy Dunlap
@ 2007-05-04 9:06 ` Satyam Sharma
2007-05-04 10:52 ` Richard Purdie
1 sibling, 1 reply; 6+ messages in thread
From: Satyam Sharma @ 2007-05-04 9:06 UTC (permalink / raw)
To: Richard Purdie; +Cc: LKML, David Woodhouse, herbert, linux-mtd, linux-crypto
Hi Richard,
On 5/1/07, Richard Purdie <rpurdie@openedhand.com> wrote:
> Add LZO1X compression/decompression support to jffs2.
>
> LZO's interface doesn't entirely match that required by jffs2 so a
> buffer and memcpy is unavoidable.
>
> Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
> ---
> [...]
> +++ b/fs/jffs2/compr_lzo.c
> [...]
> +static void *lzo_mem;
> +static void *lzo_compress_buf;
> +static DEFINE_MUTEX(deflate_mutex);
> +
> +static void free_workspace(void)
> +{
> + vfree(lzo_mem);
> + vfree(lzo_compress_buf);
> +}
> +
> +static int __init alloc_workspace(void)
> +{
> + lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
> + lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
> +
> + if (!lzo_mem || !lzo_compress_buf) {
> + printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
> + free_workspace();
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
> + uint32_t *sourcelen, uint32_t *dstlen, void *model)
> +{
> + unsigned long compress_size;
> + int ret;
> +
> + mutex_lock(&deflate_mutex);
> + ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
> + mutex_unlock(&deflate_mutex);
Considering we do have to memcpy() the entire compressed result to the
destination output buffer later anyway (note that
fs/jffs2/compr_zlib.c doesn't need to do that), do we really gain much
by avoiding vmalloc() and vfree() in jffs2_lzo_compress() itself and
keeping the workspace buffers pre-allocated? I ask because I always
found these global static workspace buffers ugly, and all the
associated code + mutex could go away if we make them local to
jffs2_lzo_compress() -- as long as it doesn't hurt performance
terribly, of course.
Thanks,
Satyam
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/5] jffs2: Add LZO compression support to jffs2
2007-05-04 9:06 ` Satyam Sharma
@ 2007-05-04 10:52 ` Richard Purdie
0 siblings, 0 replies; 6+ messages in thread
From: Richard Purdie @ 2007-05-04 10:52 UTC (permalink / raw)
To: Satyam Sharma; +Cc: LKML, David Woodhouse, herbert, linux-mtd, linux-crypto
On Fri, 2007-05-04 at 14:36 +0530, Satyam Sharma wrote:
> On 5/1/07, Richard Purdie <rpurdie@openedhand.com> wrote:
> > +++ b/fs/jffs2/compr_lzo.c
> > [...]
> > +static void *lzo_mem;
> > +static void *lzo_compress_buf;
> > +static DEFINE_MUTEX(deflate_mutex);
> > +
> > +static void free_workspace(void)
> > +{
> > + vfree(lzo_mem);
> > + vfree(lzo_compress_buf);
> > +}
> > +
> > +static int __init alloc_workspace(void)
> > +{
> > + lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
> > + lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
> > +
> > + if (!lzo_mem || !lzo_compress_buf) {
> > + printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
> > + free_workspace();
> > + return -ENOMEM;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
> > + uint32_t *sourcelen, uint32_t *dstlen, void *model)
> > +{
> > + unsigned long compress_size;
> > + int ret;
> > +
> > + mutex_lock(&deflate_mutex);
> > + ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
> > + mutex_unlock(&deflate_mutex);
>
> Considering we do have to memcpy() the entire compressed result to the
> destination output buffer later anyway (note that
> fs/jffs2/compr_zlib.c doesn't need to do that), do we really gain much
> by avoiding vmalloc() and vfree() in jffs2_lzo_compress() itself and
> keeping the workspace buffers pre-allocated? I ask because I always
> found these global static workspace buffers ugly, and all the
> associated code + mutex could go away if we make them local to
> jffs2_lzo_compress() -- as long as it doesn't hurt performance
> terribly, of course.
memcpy is relatively fast and I'd expect continually allocing and
freeing buffers to have a significant overhead compared with that and
impact performance. The current approach means you don't get ENOMEM
errors in the uncompress/compress paths either.
Regards,
Richard
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2007-05-01 14:47 [PATCH 2/5] jffs2: Add LZO compression support to jffs2 Richard Purdie
2007-05-01 20:00 ` Randy Dunlap
2007-05-04 9:06 ` Satyam Sharma
2007-05-04 10:52 ` Richard Purdie
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2007-02-28 19:13 Richard Purdie
2007-04-25 12:35 ` David Woodhouse
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