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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2014-04-07 15:38:13 -0700
committerAlex Shi <alex.shi@linaro.org>2015-05-11 20:42:00 +0800
commit9381faeb8bc1d1fdfb6931b69ee70a594d04c4fe (patch)
treebb74d864d71c78bd708f68b2c356f421b2cc2e8d
parent92e9d71d940158389d3553a382045c3c9a7a7e98 (diff)
downloadlinux-linaro-stable-9381faeb8bc1d1fdfb6931b69ee70a594d04c4fe.tar.gz
zram: factor out single stream compression
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 <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 9cc97529a180b369fcb7e5265771b6ba7e01f05b) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--drivers/block/zram/zcomp.c62
-rw-r--r--drivers/block/zram/zcomp.h7
2 files changed, 59 insertions, 10 deletions
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 22f4ae235660..72e8071f9d73 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 c9a98e1317fe..dc3500d842a3 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);