From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753437AbaB1Rzx (ORCPT ); Fri, 28 Feb 2014 12:55:53 -0500 Received: from mail-ee0-f52.google.com ([74.125.83.52]:52365 "EHLO mail-ee0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753374AbaB1Rzu (ORCPT ); Fri, 28 Feb 2014 12:55:50 -0500 From: Sergey Senozhatsky To: Minchan Kim Cc: Andrew Morton , Jerome Marchand , Nitin Gupta , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv9 3/7] zram: factor out single stream compression Date: Fri, 28 Feb 2014 20:52:03 +0300 Message-Id: <1393609927-22090-4-git-send-email-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 1.9.0.359.g5e34a15 In-Reply-To: <1393609927-22090-1-git-send-email-sergey.senozhatsky@gmail.com> References: <1393609927-22090-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is preparation patch to add multi stream support to zcomp. Introduce struct zcomp_strm_single and a set of functions to manage zcomp_strm stream access. zcomp_strm_single implements single compession stream, same way as current zcomp implementation. This moves zcomp_strm stream control and locking from zcomp, so compressing backend zcomp is not aware of required locking. Single and multi streams require different locking schemes. Minchan Kim reported that spinlock-based locking scheme (which is used in multi stream implementation) has demonstrated a severe perfomance regression for single compression stream case, comparing to mutex-based. see https://lkml.org/lkml/2014/2/18/16 The following set of functions added: - zcomp_strm_single_find()/zcomp_strm_single_release() find and release a compression stream, implement required locking - zcomp_strm_single_create()/zcomp_strm_single_destroy() create and destroy zcomp_strm_single New ->strm_find() and ->strm_release() callbacks added to zcomp, which are set to zcomp_strm_single_find() and zcomp_strm_single_release() during initialisation. Instead of direct locking and zcomp_strm access from zcomp_strm_find() and zcomp_strm_release(), zcomp now calls ->strm_find() and ->strm_release() correspondingly. Signed-off-by: Sergey Senozhatsky --- drivers/block/zram/zcomp.c | 62 ++++++++++++++++++++++++++++++++++++++++------ drivers/block/zram/zcomp.h | 7 ++++-- 2 files changed, 59 insertions(+), 10 deletions(-) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 22f4ae2..72e8071 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -16,6 +16,14 @@ #include "zcomp.h" #include "zcomp_lzo.h" +/* + * single zcomp_strm backend + */ +struct zcomp_strm_single { + struct mutex strm_lock; + struct zcomp_strm *zstrm; +}; + static struct zcomp_backend *find_backend(const char *compress) { if (strncmp(compress, "lzo", 3) == 0) @@ -54,15 +62,56 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) return zstrm; } +static struct zcomp_strm *zcomp_strm_single_find(struct zcomp *comp) +{ + struct zcomp_strm_single *zs = comp->stream; + mutex_lock(&zs->strm_lock); + return zs->zstrm; +} + +static void zcomp_strm_single_release(struct zcomp *comp, + struct zcomp_strm *zstrm) +{ + struct zcomp_strm_single *zs = comp->stream; + mutex_unlock(&zs->strm_lock); +} + +static void zcomp_strm_single_destroy(struct zcomp *comp) +{ + struct zcomp_strm_single *zs = comp->stream; + zcomp_strm_free(comp, zs->zstrm); + kfree(zs); +} + +static int zcomp_strm_single_create(struct zcomp *comp) +{ + struct zcomp_strm_single *zs; + + comp->destroy = zcomp_strm_single_destroy; + comp->strm_find = zcomp_strm_single_find; + comp->strm_release = zcomp_strm_single_release; + zs = kmalloc(sizeof(struct zcomp_strm_single), GFP_KERNEL); + if (!zs) + return -ENOMEM; + + comp->stream = zs; + mutex_init(&zs->strm_lock); + zs->zstrm = zcomp_strm_alloc(comp); + if (!zs->zstrm) { + kfree(zs); + return -ENOMEM; + } + return 0; +} + struct zcomp_strm *zcomp_strm_find(struct zcomp *comp) { - mutex_lock(&comp->strm_lock); - return comp->zstrm; + return comp->strm_find(comp); } void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm) { - mutex_unlock(&comp->strm_lock); + comp->strm_release(comp, zstrm); } int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, @@ -80,7 +129,7 @@ int zcomp_decompress(struct zcomp *comp, const unsigned char *src, void zcomp_destroy(struct zcomp *comp) { - zcomp_strm_free(comp, comp->zstrm); + comp->destroy(comp); kfree(comp); } @@ -104,10 +153,7 @@ struct zcomp *zcomp_create(const char *compress) return NULL; comp->backend = backend; - mutex_init(&comp->strm_lock); - - comp->zstrm = zcomp_strm_alloc(comp); - if (!comp->zstrm) { + if (zcomp_strm_single_create(comp) != 0) { kfree(comp); return NULL; } diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index c9a98e1..dc3500d 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -39,9 +39,12 @@ struct zcomp_backend { /* dynamic per-device compression frontend */ struct zcomp { - struct mutex strm_lock; - struct zcomp_strm *zstrm; + void *stream; struct zcomp_backend *backend; + + struct zcomp_strm *(*strm_find)(struct zcomp *comp); + void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm); + void (*destroy)(struct zcomp *comp); }; struct zcomp *zcomp_create(const char *comp); -- 1.9.0.359.g5e34a15