From: Minchan Kim Subject: Re: [PATCH v3 8/9] zram: use crypto API for compression Date: Mon, 21 Sep 2015 12:45:12 +0900 Message-ID: <20150921034512.GC27729@bbox> References: <1442553564-3476-1-git-send-email-iamjoonsoo.kim@lge.com> <1442553564-3476-9-git-send-email-iamjoonsoo.kim@lge.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , Nitin Gupta , Sergey Senozhatsky , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, Herbert Xu , "David S. Miller" , Stephan Mueller , Joonsoo Kim To: Joonsoo Kim Return-path: Received: from mail-pa0-f47.google.com ([209.85.220.47]:33731 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753481AbbIUDnq (ORCPT ); Sun, 20 Sep 2015 23:43:46 -0400 Content-Disposition: inline In-Reply-To: <1442553564-3476-9-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi Joonsoo, On Fri, Sep 18, 2015 at 02:19:23PM +0900, Joonsoo Kim wrote: > Until now, zram uses compression algorithm through direct call > to core algorithm function, but, it has drawback that we need to add > compression algorithm manually to zram if needed. Without this work, > we cannot utilize various compression algorithms in the system. > Moreover, to add new compression algorithm, we need to know how to use it > and this is somewhat time-consuming. > > When I tested new algorithms such as zlib, these problems make me hard > to test them. To prevent these problem in the future, I think that > using crypto API for compression is better approach and this patch > implements it. > > The reason we need to support vairous compression algorithms is that > zram's performance is highly depend on workload and compression algorithm > and architecture. Every compression algorithm has it's own strong point. > For example, zlib is the best for compression ratio, but, it's > (de)compression speed is rather slow. Against my expectation, in my kernel > build test with zram swap, in low-memory condition on x86, zlib shows best > performance than others. In this case, I guess that compression ratio is > the most important factor. Unlike this situation, on ARM, maybe fast > (de)compression speed is the most important because it's computation speed > is slower than x86. > > We can't expect what algorithm is the best fit for one's system, because > it needs too complex calculation. We need to test it in case by case and > easy to use new compression algorithm by this patch will help > that situation. > > There is one problem that crypto API requires tfm object to (de)compress > something and zram abstract it on zstrm which is very limited resource. > If number of zstrm is set to low and is contended, zram's performace could > be down-graded due to this change. But, following patch support to use > crypto decompress_noctx API and would restore the performance as is. > > Signed-off-by: Joonsoo Kim > --- > drivers/block/zram/Kconfig | 8 +++---- > drivers/block/zram/Makefile | 4 +--- > drivers/block/zram/zcomp.c | 54 +++++++++++++++++++++++------------------- > drivers/block/zram/zcomp.h | 30 ++++++----------------- > drivers/block/zram/zcomp_lz4.c | 47 ------------------------------------ > drivers/block/zram/zcomp_lz4.h | 17 ------------- > drivers/block/zram/zcomp_lzo.c | 47 ------------------------------------ > drivers/block/zram/zcomp_lzo.h | 17 ------------- > drivers/block/zram/zram_drv.c | 6 ++--- > 9 files changed, 44 insertions(+), 186 deletions(-) > delete mode 100644 drivers/block/zram/zcomp_lz4.c > delete mode 100644 drivers/block/zram/zcomp_lz4.h > delete mode 100644 drivers/block/zram/zcomp_lzo.c > delete mode 100644 drivers/block/zram/zcomp_lzo.h > > diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig > index 386ba3d..7619bed 100644 > --- a/drivers/block/zram/Kconfig > +++ b/drivers/block/zram/Kconfig > @@ -1,8 +1,7 @@ > config ZRAM > tristate "Compressed RAM block device support" > depends on BLOCK && SYSFS && ZSMALLOC > - select LZO_COMPRESS > - select LZO_DECOMPRESS > + select CRYPTO_LZO > default n > help > Creates virtual block devices called /dev/zramX (X = 0, 1, ...). > @@ -18,9 +17,8 @@ config ZRAM > config ZRAM_LZ4_COMPRESS > bool "Enable LZ4 algorithm support" > depends on ZRAM > - select LZ4_COMPRESS > - select LZ4_DECOMPRESS > + select CRYPTO_LZ4 It is out of my expectation. When I heard crypto support for zRAM first, I imagined zram user can use any crypto compressor algorithm easily if system has the algorithm. IOW, I expect zRAM shouldn't bind CONFIG_CRYPTO_ALGONAME statically except the default one(ie, CONFIG_CRYPTO_LZO) like zswap and It seems you did in eariler version. You seem to have a trouble to adapt crypto to current comp_algorithm because crypto doesn't export any API to enumerate algorithm name while zram should export supporting algorithm name via comp_algorithm and I heard crypto maintainer doesn't want to export it. Instead, user can use /proc/crypto to know what kinds of compressor system can support. Hmm, At the first glance, I was about to say "let's sort it out with futher patches" but I changed my mind. ;-). We should sort it out before you are adding zlib support(ie, please include zlib support patch with number data in this patchset). Otherwise, we should add new hard-wired stuff for zlib like lzo, lz4 to comp_algorithm and will depreate soon. My idea is ABI change of comp_algorithm. Namely, let's deprecate it and guide to use /proc/crypto to show available compressor. Someday, we removes backends string array finally. Welcome to any ideas. > default n > help > This option enables LZ4 compression algorithm support. Compression > - algorithm can be changed using `comp_algorithm' device attribute. > \ No newline at end of file > + algorithm can be changed using `comp_algorithm' device attribute. > diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile > index be0763f..9e2b79e 100644 > --- a/drivers/block/zram/Makefile > +++ b/drivers/block/zram/Makefile > @@ -1,5 +1,3 @@ > -zram-y := zcomp_lzo.o zcomp.o zram_drv.o > - > -zram-$(CONFIG_ZRAM_LZ4_COMPRESS) += zcomp_lz4.o > +zram-y := zcomp.o zram_drv.o > > obj-$(CONFIG_ZRAM) += zram.o > diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c > index 3456d5a..c2ed7c8 100644 > --- a/drivers/block/zram/zcomp.c > +++ b/drivers/block/zram/zcomp.c > @@ -15,10 +15,6 @@ > #include > > #include "zcomp.h" > -#include "zcomp_lzo.h" > -#ifdef CONFIG_ZRAM_LZ4_COMPRESS > -#include "zcomp_lz4.h" > -#endif > > /* > * single zcomp_strm backend > @@ -43,19 +39,20 @@ struct zcomp_strm_multi { > wait_queue_head_t strm_wait; > }; > > -static struct zcomp_backend *backends[] = { > - &zcomp_lzo, > +static const char * const backends[] = { > + "lzo", > #ifdef CONFIG_ZRAM_LZ4_COMPRESS > - &zcomp_lz4, > + "lz4", > #endif > NULL > }; > > -static struct zcomp_backend *find_backend(const char *compress) > +static const char *find_backend(const char *compress) > { > int i = 0; > while (backends[i]) { > - if (sysfs_streq(compress, backends[i]->name)) > + if (sysfs_streq(compress, backends[i]) && > + crypto_has_comp(compress, 0, 0)) > break; > i++; > } > @@ -64,8 +61,8 @@ static struct zcomp_backend *find_backend(const char *compress) > > static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) > { > - if (zstrm->private) > - comp->backend->destroy(zstrm->private); > + if (zstrm->tfm) > + crypto_free_comp(zstrm->tfm); > free_pages((unsigned long)zstrm->buffer, 1); > kfree(zstrm); > } > @@ -80,13 +77,18 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) > if (!zstrm) > return NULL; > > - zstrm->private = comp->backend->create(); > + zstrm->tfm = crypto_alloc_comp(comp->backend, 0, 0); > + if (IS_ERR(zstrm->tfm)) { > + kfree(zstrm); > + return NULL; > + } > + > /* > * allocate 2 pages. 1 for compressed data, plus 1 extra for the > * case when compressed size is larger than the original one > */ > zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); > - if (!zstrm->private || !zstrm->buffer) { > + if (!zstrm->buffer) { > zcomp_strm_free(comp, zstrm); > zstrm = NULL; > } > @@ -274,12 +276,12 @@ ssize_t zcomp_available_show(const char *comp, char *buf) > int i = 0; > > while (backends[i]) { > - if (!strcmp(comp, backends[i]->name)) > + if (!strcmp(comp, backends[i])) > sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, > - "[%s] ", backends[i]->name); > + "[%s] ", backends[i]); > else > sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, > - "%s ", backends[i]->name); > + "%s ", backends[i]); > i++; > } > sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n"); > @@ -317,10 +319,10 @@ void zcomp_compress_end(struct zcomp *comp, struct zcomp_strm *zstrm) > zcomp_strm_release(comp, zstrm); > } > > -/* May return NULL, may sleep */ > +/* Never return NULL, may sleep */ > struct zcomp_strm *zcomp_decompress_begin(struct zcomp *comp) > { > - return NULL; > + return zcomp_strm_find(comp); > } > > void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm) > @@ -330,17 +332,21 @@ void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm) > } > > int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, > - const unsigned char *src, size_t *dst_len) > + const unsigned char *src, unsigned int *dst_len) > { > - return comp->backend->compress(src, zstrm->buffer, dst_len, > - zstrm->private); > + *dst_len = PAGE_SIZE << 1; > + > + return crypto_comp_compress(zstrm->tfm, src, PAGE_SIZE, > + zstrm->buffer, dst_len); > } > > int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm, > const unsigned char *src, > - size_t src_len, unsigned char *dst) > + unsigned int src_len, unsigned char *dst) > { > - return comp->backend->decompress(src, src_len, dst); > + unsigned int size = PAGE_SIZE; > + > + return crypto_comp_decompress(zstrm->tfm, src, src_len, dst, &size); > } > > void zcomp_destroy(struct zcomp *comp) > @@ -359,7 +365,7 @@ void zcomp_destroy(struct zcomp *comp) > struct zcomp *zcomp_create(const char *compress, int max_strm) > { > struct zcomp *comp; > - struct zcomp_backend *backend; > + const char *backend; > > backend = find_backend(compress); > if (!backend) > diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h > index 4c09c01..4f9df8e 100644 > --- a/drivers/block/zram/zcomp.h > +++ b/drivers/block/zram/zcomp.h > @@ -11,38 +11,22 @@ > #define _ZCOMP_H_ > > #include > +#include > > struct zcomp_strm { > + struct crypto_comp *tfm; > + > /* compression/decompression buffer */ > void *buffer; > - /* > - * The private data of the compression stream, only compression > - * stream backend can touch this (e.g. compression algorithm > - * working memory) > - */ > - void *private; > + > /* used in multi stream backend, protected by backend strm_lock */ > struct list_head list; > }; > > -/* static compression backend */ > -struct zcomp_backend { > - int (*compress)(const unsigned char *src, unsigned char *dst, > - size_t *dst_len, void *private); > - > - int (*decompress)(const unsigned char *src, size_t src_len, > - unsigned char *dst); > - > - void *(*create)(void); > - void (*destroy)(void *private); > - > - const char *name; > -}; > - > /* dynamic per-device compression frontend */ > struct zcomp { > void *stream; > - struct zcomp_backend *backend; > + const char *backend; > > struct zcomp_strm *(*strm_find)(struct zcomp *comp); > void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm); > @@ -61,14 +45,14 @@ struct zcomp_strm *zcomp_compress_begin(struct zcomp *comp); > void zcomp_compress_end(struct zcomp *comp, struct zcomp_strm *zstrm); > > int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, > - const unsigned char *src, size_t *dst_len); > + const unsigned char *src, unsigned int *dst_len); > > struct zcomp_strm *zcomp_decompress_begin(struct zcomp *comp); > void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm); > > int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm, > const unsigned char *src, > - size_t src_len, unsigned char *dst); > + unsigned int src_len, unsigned char *dst); > > bool zcomp_set_max_streams(struct zcomp *comp, int num_strm); > #endif /* _ZCOMP_H_ */ > diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c > deleted file mode 100644 > index f2afb7e..0000000 > --- a/drivers/block/zram/zcomp_lz4.c > +++ /dev/null > @@ -1,47 +0,0 @@ > -/* > - * Copyright (C) 2014 Sergey Senozhatsky. > - * > - * This program is free software; you can redistribute it and/or > - * modify it under the terms of the GNU General Public License > - * as published by the Free Software Foundation; either version > - * 2 of the License, or (at your option) any later version. > - */ > - > -#include > -#include > -#include > - > -#include "zcomp_lz4.h" > - > -static void *zcomp_lz4_create(void) > -{ > - return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL); > -} > - > -static void zcomp_lz4_destroy(void *private) > -{ > - kfree(private); > -} > - > -static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst, > - size_t *dst_len, void *private) > -{ > - /* return : Success if return 0 */ > - return lz4_compress(src, PAGE_SIZE, dst, dst_len, private); > -} > - > -static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len, > - unsigned char *dst) > -{ > - size_t dst_len = PAGE_SIZE; > - /* return : Success if return 0 */ > - return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len); > -} > - > -struct zcomp_backend zcomp_lz4 = { > - .compress = zcomp_lz4_compress, > - .decompress = zcomp_lz4_decompress, > - .create = zcomp_lz4_create, > - .destroy = zcomp_lz4_destroy, > - .name = "lz4", > -}; > diff --git a/drivers/block/zram/zcomp_lz4.h b/drivers/block/zram/zcomp_lz4.h > deleted file mode 100644 > index 60613fb..0000000 > --- a/drivers/block/zram/zcomp_lz4.h > +++ /dev/null > @@ -1,17 +0,0 @@ > -/* > - * Copyright (C) 2014 Sergey Senozhatsky. > - * > - * This program is free software; you can redistribute it and/or > - * modify it under the terms of the GNU General Public License > - * as published by the Free Software Foundation; either version > - * 2 of the License, or (at your option) any later version. > - */ > - > -#ifndef _ZCOMP_LZ4_H_ > -#define _ZCOMP_LZ4_H_ > - > -#include "zcomp.h" > - > -extern struct zcomp_backend zcomp_lz4; > - > -#endif /* _ZCOMP_LZ4_H_ */ > diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c > deleted file mode 100644 > index da1bc47..0000000 > --- a/drivers/block/zram/zcomp_lzo.c > +++ /dev/null > @@ -1,47 +0,0 @@ > -/* > - * Copyright (C) 2014 Sergey Senozhatsky. > - * > - * This program is free software; you can redistribute it and/or > - * modify it under the terms of the GNU General Public License > - * as published by the Free Software Foundation; either version > - * 2 of the License, or (at your option) any later version. > - */ > - > -#include > -#include > -#include > - > -#include "zcomp_lzo.h" > - > -static void *lzo_create(void) > -{ > - return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); > -} > - > -static void lzo_destroy(void *private) > -{ > - kfree(private); > -} > - > -static int lzo_compress(const unsigned char *src, unsigned char *dst, > - size_t *dst_len, void *private) > -{ > - int ret = lzo1x_1_compress(src, PAGE_SIZE, dst, dst_len, private); > - return ret == LZO_E_OK ? 0 : ret; > -} > - > -static int lzo_decompress(const unsigned char *src, size_t src_len, > - unsigned char *dst) > -{ > - size_t dst_len = PAGE_SIZE; > - int ret = lzo1x_decompress_safe(src, src_len, dst, &dst_len); > - return ret == LZO_E_OK ? 0 : ret; > -} > - > -struct zcomp_backend zcomp_lzo = { > - .compress = lzo_compress, > - .decompress = lzo_decompress, > - .create = lzo_create, > - .destroy = lzo_destroy, > - .name = "lzo", > -}; > diff --git a/drivers/block/zram/zcomp_lzo.h b/drivers/block/zram/zcomp_lzo.h > deleted file mode 100644 > index 128c580..0000000 > --- a/drivers/block/zram/zcomp_lzo.h > +++ /dev/null > @@ -1,17 +0,0 @@ > -/* > - * Copyright (C) 2014 Sergey Senozhatsky. > - * > - * This program is free software; you can redistribute it and/or > - * modify it under the terms of the GNU General Public License > - * as published by the Free Software Foundation; either version > - * 2 of the License, or (at your option) any later version. > - */ > - > -#ifndef _ZCOMP_LZO_H_ > -#define _ZCOMP_LZO_H_ > - > -#include "zcomp.h" > - > -extern struct zcomp_backend zcomp_lzo; > - > -#endif /* _ZCOMP_LZO_H_ */ > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 55e09db1..834f452 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -567,7 +567,7 @@ static int zram_decompress_page(struct zram *zram, struct zcomp_strm *zstrm, > unsigned char *cmem; > struct zram_meta *meta = zram->meta; > unsigned long handle; > - size_t size; > + unsigned int size; > > bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); > handle = meta->table[index].handle; > @@ -656,7 +656,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, > int offset) > { > int ret = 0; > - size_t clen; > + unsigned int clen; > unsigned long handle; > struct page *page; > unsigned char *user_mem, *cmem, *src, *uncmem = NULL; > @@ -731,7 +731,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, > > handle = zs_malloc(meta->mem_pool, clen); > if (!handle) { > - pr_err("Error allocating memory for compressed page: %u, size=%zu\n", > + pr_err("Error allocating memory for compressed page: %u, size=%u\n", > index, clen); > ret = -ENOMEM; > goto out; > -- > 1.9.1 >