Introduce support of algorithm specific parameters in
algorithm_params device attribute. The expected format
is algorithm.param=value.
For starters, add support for deflate.winbits parameter.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
drivers/block/zram/backend_deflate.c | 10 ++++++----
drivers/block/zram/zcomp.h | 7 +++++++
drivers/block/zram/zram_drv.c | 17 +++++++++++++++--
3 files changed, 28 insertions(+), 6 deletions(-)
diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
index 4c00b5b6739f..b75016e0e654 100644
--- a/drivers/block/zram/backend_deflate.c
+++ b/drivers/block/zram/backend_deflate.c
@@ -8,7 +8,7 @@
#include "backend_deflate.h"
/* Use the same value as crypto API */
-#define DEFLATE_DEF_WINBITS 11
+#define DEFLATE_DEF_WINBITS (-11)
#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
struct deflate_ctx {
@@ -24,6 +24,8 @@ static int deflate_setup_params(struct zcomp_params *params)
{
if (params->level == ZCOMP_PARAM_NOT_SET)
params->level = Z_DEFAULT_COMPRESSION;
+ if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
+ params->deflate.winbits = DEFLATE_DEF_WINBITS;
return 0;
}
@@ -57,13 +59,13 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
return -ENOMEM;
ctx->context = zctx;
- sz = zlib_deflate_workspacesize(-DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL);
+ sz = zlib_deflate_workspacesize(params->deflate.winbits, MAX_MEM_LEVEL);
zctx->cctx.workspace = vzalloc(sz);
if (!zctx->cctx.workspace)
goto error;
ret = zlib_deflateInit2(&zctx->cctx, params->level, Z_DEFLATED,
- -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
+ params->deflate.winbits, DEFLATE_DEF_MEMLEVEL,
Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
goto error;
@@ -73,7 +75,7 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
if (!zctx->dctx.workspace)
goto error;
- ret = zlib_inflateInit2(&zctx->dctx, -DEFLATE_DEF_WINBITS);
+ ret = zlib_inflateInit2(&zctx->dctx, params->deflate.winbits);
if (ret != Z_OK)
goto error;
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index cfacdfe9044c..4acffe671a5e 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -7,6 +7,10 @@
#define ZCOMP_PARAM_NOT_SET INT_MIN
+struct deflate_params {
+ s32 winbits;
+};
+
/*
* Immutable driver (backend) parameters. The driver may attach private
* data to it (e.g. driver representation of the dictionary, etc.).
@@ -17,6 +21,9 @@ struct zcomp_params {
void *dict;
size_t dict_sz;
s32 level;
+ union {
+ struct deflate_params deflate;
+ };
void *drv_data;
};
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a11b7a6e35f4..54c57103715f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1277,12 +1277,14 @@ static void comp_params_reset(struct zram *zram, u32 prio)
vfree(params->dict);
params->level = ZCOMP_PARAM_NOT_SET;
+ params->deflate.winbits = ZCOMP_PARAM_NOT_SET;
params->dict_sz = 0;
params->dict = NULL;
}
static int comp_params_store(struct zram *zram, u32 prio, s32 level,
- const char *dict_path)
+ const char *dict_path,
+ struct deflate_params *deflate_params)
{
ssize_t sz = 0;
@@ -1300,6 +1302,7 @@ static int comp_params_store(struct zram *zram, u32 prio, s32 level,
zram->params[prio].dict_sz = sz;
zram->params[prio].level = level;
+ zram->params[prio].deflate.winbits = deflate_params->winbits;
return 0;
}
@@ -1310,9 +1313,12 @@ static ssize_t algorithm_params_store(struct device *dev,
{
s32 prio = ZRAM_PRIMARY_COMP, level = ZCOMP_PARAM_NOT_SET;
char *args, *param, *val, *algo = NULL, *dict_path = NULL;
+ struct deflate_params deflate_params;
struct zram *zram = dev_to_zram(dev);
int ret;
+ deflate_params.winbits = ZCOMP_PARAM_NOT_SET;
+
args = skip_spaces(buf);
while (*args) {
args = next_arg(args, ¶m, &val);
@@ -1343,6 +1349,13 @@ static ssize_t algorithm_params_store(struct device *dev,
dict_path = val;
continue;
}
+
+ if (!strcmp(param, "deflate.winbits")) {
+ ret = kstrtoint(val, 10, &deflate_params.winbits);
+ if (ret)
+ return ret;
+ continue;
+ }
}
/* Lookup priority by algorithm name */
@@ -1364,7 +1377,7 @@ static ssize_t algorithm_params_store(struct device *dev,
if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
return -EINVAL;
- ret = comp_params_store(zram, prio, level, dict_path);
+ ret = comp_params_store(zram, prio, level, dict_path, &deflate_params);
return ret ? ret : len;
}
--
2.49.0.1045.g170613ef41-googLooks good to me.
Just a minor comment. If we intend to use raw deflate only, like we do now (no zlib header or
trailer for the compressed data), we should probably change deflate.winbits to unsigned and
pass '-deflate.winbits' to zlib_deflateInit2().
Also, here is another patch suggestion from my side on top of this one.
Let me know what you think.
---8<---
zram: Utilize s390 hardware deflate acceleration for zram
Utilize s390 hardware deflate acceleration for zram deflate compression
by default when the facility is available.
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
index b75016e0e654..5bfc57522e3a 100644
--- a/drivers/block/zram/backend_deflate.c
+++ b/drivers/block/zram/backend_deflate.c
@@ -22,10 +22,23 @@ static void deflate_release_params(struct zcomp_params *params)
static int deflate_setup_params(struct zcomp_params *params)
{
- if (params->level == ZCOMP_PARAM_NOT_SET)
- params->level = Z_DEFAULT_COMPRESSION;
- if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
- params->deflate.winbits = DEFLATE_DEF_WINBITS;
+ /*
+ * In case of s390 zlib hardware support available,
+ * use maximum window size and level one as default compression
+ * parameters in order to utilize hardware deflate acceleration.
+ */
+ if (params->level == ZCOMP_PARAM_NOT_SET) {
+ if (zlib_deflate_dfltcc_enabled())
+ params->level = Z_BEST_SPEED;
+ else
+ params->level = Z_DEFAULT_COMPRESSION;
+ }
+ if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET) {
+ if (zlib_deflate_dfltcc_enabled())
+ params->deflate.winbits = -MAX_WBITS;
+ else
+ params->deflate.winbits = DEFLATE_DEF_WINBITS;
+ }
return 0;
}
On 14.05.2025 04:47, Sergey Senozhatsky wrote:
> Introduce support of algorithm specific parameters in
> algorithm_params device attribute. The expected format
> is algorithm.param=value.
>
> For starters, add support for deflate.winbits parameter.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
> drivers/block/zram/backend_deflate.c | 10 ++++++----
> drivers/block/zram/zcomp.h | 7 +++++++
> drivers/block/zram/zram_drv.c | 17 +++++++++++++++--
> 3 files changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
> index 4c00b5b6739f..b75016e0e654 100644
> --- a/drivers/block/zram/backend_deflate.c
> +++ b/drivers/block/zram/backend_deflate.c
> @@ -8,7 +8,7 @@
> #include "backend_deflate.h"
>
> /* Use the same value as crypto API */
> -#define DEFLATE_DEF_WINBITS 11
> +#define DEFLATE_DEF_WINBITS (-11)
> #define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
>
> struct deflate_ctx {
> @@ -24,6 +24,8 @@ static int deflate_setup_params(struct zcomp_params *params)
> {
> if (params->level == ZCOMP_PARAM_NOT_SET)
> params->level = Z_DEFAULT_COMPRESSION;
> + if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
> + params->deflate.winbits = DEFLATE_DEF_WINBITS;
>
> return 0;
> }
> @@ -57,13 +59,13 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
> return -ENOMEM;
>
> ctx->context = zctx;
> - sz = zlib_deflate_workspacesize(-DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL);
> + sz = zlib_deflate_workspacesize(params->deflate.winbits, MAX_MEM_LEVEL);
> zctx->cctx.workspace = vzalloc(sz);
> if (!zctx->cctx.workspace)
> goto error;
>
> ret = zlib_deflateInit2(&zctx->cctx, params->level, Z_DEFLATED,
> - -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
> + params->deflate.winbits, DEFLATE_DEF_MEMLEVEL,
> Z_DEFAULT_STRATEGY);
> if (ret != Z_OK)
> goto error;
> @@ -73,7 +75,7 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
> if (!zctx->dctx.workspace)
> goto error;
>
> - ret = zlib_inflateInit2(&zctx->dctx, -DEFLATE_DEF_WINBITS);
> + ret = zlib_inflateInit2(&zctx->dctx, params->deflate.winbits);
> if (ret != Z_OK)
> goto error;
>
> diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
> index cfacdfe9044c..4acffe671a5e 100644
> --- a/drivers/block/zram/zcomp.h
> +++ b/drivers/block/zram/zcomp.h
> @@ -7,6 +7,10 @@
>
> #define ZCOMP_PARAM_NOT_SET INT_MIN
>
> +struct deflate_params {
> + s32 winbits;
> +};
> +
> /*
> * Immutable driver (backend) parameters. The driver may attach private
> * data to it (e.g. driver representation of the dictionary, etc.).
> @@ -17,6 +21,9 @@ struct zcomp_params {
> void *dict;
> size_t dict_sz;
> s32 level;
> + union {
> + struct deflate_params deflate;
> + };
>
> void *drv_data;
> };
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index a11b7a6e35f4..54c57103715f 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -1277,12 +1277,14 @@ static void comp_params_reset(struct zram *zram, u32 prio)
>
> vfree(params->dict);
> params->level = ZCOMP_PARAM_NOT_SET;
> + params->deflate.winbits = ZCOMP_PARAM_NOT_SET;
> params->dict_sz = 0;
> params->dict = NULL;
> }
>
> static int comp_params_store(struct zram *zram, u32 prio, s32 level,
> - const char *dict_path)
> + const char *dict_path,
> + struct deflate_params *deflate_params)
> {
> ssize_t sz = 0;
>
> @@ -1300,6 +1302,7 @@ static int comp_params_store(struct zram *zram, u32 prio, s32 level,
>
> zram->params[prio].dict_sz = sz;
> zram->params[prio].level = level;
> + zram->params[prio].deflate.winbits = deflate_params->winbits;
> return 0;
> }
>
> @@ -1310,9 +1313,12 @@ static ssize_t algorithm_params_store(struct device *dev,
> {
> s32 prio = ZRAM_PRIMARY_COMP, level = ZCOMP_PARAM_NOT_SET;
> char *args, *param, *val, *algo = NULL, *dict_path = NULL;
> + struct deflate_params deflate_params;
> struct zram *zram = dev_to_zram(dev);
> int ret;
>
> + deflate_params.winbits = ZCOMP_PARAM_NOT_SET;
> +
> args = skip_spaces(buf);
> while (*args) {
> args = next_arg(args, ¶m, &val);
> @@ -1343,6 +1349,13 @@ static ssize_t algorithm_params_store(struct device *dev,
> dict_path = val;
> continue;
> }
> +
> + if (!strcmp(param, "deflate.winbits")) {
> + ret = kstrtoint(val, 10, &deflate_params.winbits);
> + if (ret)
> + return ret;
> + continue;
> + }
> }
>
> /* Lookup priority by algorithm name */
> @@ -1364,7 +1377,7 @@ static ssize_t algorithm_params_store(struct device *dev,
> if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
> return -EINVAL;
>
> - ret = comp_params_store(zram, prio, level, dict_path);
> + ret = comp_params_store(zram, prio, level, dict_path, &deflate_params);
> return ret ? ret : len;
> }
>
Cc-ing Herbert
On (25/05/14 12:58), Zaslonko Mikhail wrote:
> Looks good to me.
>
> Just a minor comment. If we intend to use raw deflate only, like we do now (no zlib header or
> trailer for the compressed data), we should probably change deflate.winbits to unsigned and
> pass '-deflate.winbits' to zlib_deflateInit2().
Yeah, so in zram we can use only raw deflate (we decompress only what we
have compressed earlier and the data never leaves the device.) But in case
of Crypto API I actually don't know, added Herbert to the Cc.
> Also, here is another patch suggestion from my side on top of this one.
> Let me know what you think.
>
> ---8<---
>
> zram: Utilize s390 hardware deflate acceleration for zram
>
> Utilize s390 hardware deflate acceleration for zram deflate compression
> by default when the facility is available.
>
> Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
>
> diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
> index b75016e0e654..5bfc57522e3a 100644
> --- a/drivers/block/zram/backend_deflate.c
> +++ b/drivers/block/zram/backend_deflate.c
> @@ -22,10 +22,23 @@ static void deflate_release_params(struct zcomp_params *params)
>
> static int deflate_setup_params(struct zcomp_params *params)
> {
> - if (params->level == ZCOMP_PARAM_NOT_SET)
> - params->level = Z_DEFAULT_COMPRESSION;
> - if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
> - params->deflate.winbits = DEFLATE_DEF_WINBITS;
> + /*
> + * In case of s390 zlib hardware support available,
> + * use maximum window size and level one as default compression
> + * parameters in order to utilize hardware deflate acceleration.
> + */
> + if (params->level == ZCOMP_PARAM_NOT_SET) {
> + if (zlib_deflate_dfltcc_enabled())
> + params->level = Z_BEST_SPEED;
> + else
> + params->level = Z_DEFAULT_COMPRESSION;
> + }
> + if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET) {
> + if (zlib_deflate_dfltcc_enabled())
> + params->deflate.winbits = -MAX_WBITS;
> + else
> + params->deflate.winbits = DEFLATE_DEF_WINBITS;
> + }
I'm not sure if we want this much of s390 specific code in the generic
zram/Crypto API code. Both of these params can be configured by user-space
via the algorithm_params device attribute.
Hello,
On 15.05.2025 05:14, Sergey Senozhatsky wrote:
> Cc-ing Herbert
>
> On (25/05/14 12:58), Zaslonko Mikhail wrote:
>> Looks good to me.
>>
>> Also, here is another patch suggestion from my side on top of this one.
>> Let me know what you think.
>>
>> ---8<---
>>
>> zram: Utilize s390 hardware deflate acceleration for zram
>>
>> Utilize s390 hardware deflate acceleration for zram deflate compression
>> by default when the facility is available.
>>
>> Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
>>
>> diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
>> index b75016e0e654..5bfc57522e3a 100644
>> --- a/drivers/block/zram/backend_deflate.c
>> +++ b/drivers/block/zram/backend_deflate.c
>> @@ -22,10 +22,23 @@ static void deflate_release_params(struct zcomp_params *params)
>>
>> static int deflate_setup_params(struct zcomp_params *params)
>> {
>> - if (params->level == ZCOMP_PARAM_NOT_SET)
>> - params->level = Z_DEFAULT_COMPRESSION;
>> - if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
>> - params->deflate.winbits = DEFLATE_DEF_WINBITS;
>> + /*
>> + * In case of s390 zlib hardware support available,
>> + * use maximum window size and level one as default compression
>> + * parameters in order to utilize hardware deflate acceleration.
>> + */
>> + if (params->level == ZCOMP_PARAM_NOT_SET) {
>> + if (zlib_deflate_dfltcc_enabled())
>> + params->level = Z_BEST_SPEED;
>> + else
>> + params->level = Z_DEFAULT_COMPRESSION;
>> + }
>> + if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET) {
>> + if (zlib_deflate_dfltcc_enabled())
>> + params->deflate.winbits = -MAX_WBITS;
>> + else
>> + params->deflate.winbits = DEFLATE_DEF_WINBITS;
>> + }
>
> I'm not sure if we want this much of s390 specific code in the generic
> zram/Crypto API code. Both of these params can be configured by user-space
> via the algorithm_params device attribute.
I understand the concern. My intention was to use special defaults for s390
when no algorithm_params configured by the user (which is the common case,
I assume). Do you see other way of doing so without touching zram generic
code?
Thanks,
Mikhail
On Thu, May 15, 2025 at 12:14:38PM +0900, Sergey Senozhatsky wrote: > > Yeah, so in zram we can use only raw deflate (we decompress only what we > have compressed earlier and the data never leaves the device.) But in case > of Crypto API I actually don't know, added Herbert to the Cc. The Crypto API has only ever used the raw deflate format. Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
On (25/05/15 11:17), Herbert Xu wrote: > On Thu, May 15, 2025 at 12:14:38PM +0900, Sergey Senozhatsky wrote: > > > > Yeah, so in zram we can use only raw deflate (we decompress only what we > > have compressed earlier and the data never leaves the device.) But in case > > of Crypto API I actually don't know, added Herbert to the Cc. > > The Crypto API has only ever used the raw deflate format. OK, so do we want to limit user-space and permit only "raw deflate" winbits values. that is only negative ones (either explicitly or implicitly (by negating the value before zlib API calls))?
On Thu, May 15, 2025 at 12:19:25PM +0900, Sergey Senozhatsky wrote: > > OK, so do we want to limit user-space and permit only "raw deflate" > winbits values. that is only negative ones (either explicitly or > implicitly (by negating the value before zlib API calls))? I would suggest that we stick with the zlib values, but filter out the ones that we don't support/use currently. If you've already exported this to user-space then obviously you'll need to decide on how to maintain compatibility but that should be specific to zram. Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
On (25/05/15 11:24), Herbert Xu wrote:
> On Thu, May 15, 2025 at 12:19:25PM +0900, Sergey Senozhatsky wrote:
> >
> > OK, so do we want to limit user-space and permit only "raw deflate"
> > winbits values. that is only negative ones (either explicitly or
> > implicitly (by negating the value before zlib API calls))?
>
> I would suggest that we stick with the zlib values, but filter
> out the ones that we don't support/use currently. If you've already
> exported this to user-space then obviously you'll need to decide
> on how to maintain compatibility but that should be specific to
> zram.
This is not exported yet.
I lean toward not filtering/limiting anything and just permit
what include/linux/zlib.h promises [1]. Would that be OK for
Crypto API?
[1]
----
The windowBits parameter is the base two logarithm of the maximum window
size (the size of the history buffer). It should be in the range 8..15 for
this version of the library. The default value is 15 if inflateInit is used
instead. windowBits must be greater than or equal to the windowBits value
provided to deflateInit2() while compressing, or it must be equal to 15 if
deflateInit2() was not used. If a compressed stream with a larger window
size is given as input, inflate() will return with the error code
Z_DATA_ERROR instead of trying to allocate a larger window.
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
determines the window size. inflate() will then process raw deflate data,
not looking for a zlib or gzip header, not generating a check value, and not
looking for any check values for comparison at the end of the stream. This
is for use with other formats that use the deflate compressed data format
such as zip. Those formats provide their own check values. If a custom
format is developed using the raw deflate format for compressed data, it is
recommended that a check value such as an adler32 or a crc32 be applied to
the uncompressed data as is done in the zlib, gzip, and zip formats. For
most applications, the zlib format should be used as is. Note that comments
above on the use in deflateInit2() applies to the magnitude of windowBits.
windowBits can also be greater than 15 for optional gzip decoding. Add
32 to windowBits to enable zlib and gzip decoding with automatic header
detection, or add 16 to decode only the gzip format (the zlib format will
return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
a crc32 instead of an adler32.
On Thu, May 15, 2025 at 12:32:39PM +0900, Sergey Senozhatsky wrote: > > This is not exported yet. > > I lean toward not filtering/limiting anything and just permit > what include/linux/zlib.h promises [1]. Would that be OK for > Crypto API? I don't have a problem with that. It just makes the hardware implementor's job a little bit harder, because the Crypto API requires every implementation of a given algorithm to be equivalent. So if the software zlib supports a full level specification, then so must the s390 version of zlib. If it cannot support a parameter, then it must provide a software fallback. Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
Hello, On 15.05.2025 05:38, Herbert Xu wrote: > On Thu, May 15, 2025 at 12:32:39PM +0900, Sergey Senozhatsky wrote: >> >> This is not exported yet. >> >> I lean toward not filtering/limiting anything and just permit >> what include/linux/zlib.h promises [1]. Would that be OK for >> Crypto API? > > I don't have a problem with that. > > It just makes the hardware implementor's job a little bit harder, > because the Crypto API requires every implementation of a given > algorithm to be equivalent. So if the software zlib supports > a full level specification, then so must the s390 version of zlib. > If it cannot support a parameter, then it must provide a software > fallback. That's exactly how s390 zlib hardware support works, including fallback to software. My intention was to use specific zlib compression parameters (window size and compression level), as default values for zram delflate on s390 to benefit from hardware acceleration. > > Cheers, Thanks, Mikhail
© 2016 - 2026 Red Hat, Inc.