linux-kernel - Re: [PATCH 1/3] zram/zcomp: use GFP

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Date:	Tue, 24 Nov 2015 15:00:37 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Kyeongdon Kim <kyeongdon.kim@....com>,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Subject: Re: [PATCH 1/3] zram/zcomp: use GFP_NOIO to allocate streams

[..]
>  static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
>  {
> -       struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
> +       struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO);
>         if (!zstrm)
>                 return NULL;
> 
> @@ -85,7 +85,7 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
>          * 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);
> +       zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_ZERO, 1);
>         if (!zstrm->private || !zstrm->buffer) {
>                 zcomp_strm_free(comp, zstrm);
>                 zstrm = NULL;

hm... this is not enough.
we allocate

	stream GFP_NOIO
	stream private GFP_KERNEL    <<<< still old flags
	stream buffer

so my patch was something like this:

---

 drivers/block/zram/zcomp.c     | 4 ++--
 drivers/block/zram/zcomp_lz4.c | 2 +-
 drivers/block/zram/zcomp_lzo.c | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 5cb13ca..c536177 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -76,7 +76,7 @@ static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
  */
 static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
 {
-	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
+	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO);
 	if (!zstrm)
 		return NULL;
 
@@ -85,7 +85,7 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
 	 * 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);
+	zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_ZERO, 1);
 	if (!zstrm->private || !zstrm->buffer) {
 		zcomp_strm_free(comp, zstrm);
 		zstrm = NULL;
diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c
index f2afb7e..ee44b51 100644
--- a/drivers/block/zram/zcomp_lz4.c
+++ b/drivers/block/zram/zcomp_lz4.c
@@ -15,7 +15,7 @@
 
 static void *zcomp_lz4_create(void)
 {
-	return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
+	return kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO);
 }
 
 static void zcomp_lz4_destroy(void *private)
diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c
index da1bc47..683ce04 100644
--- a/drivers/block/zram/zcomp_lzo.c
+++ b/drivers/block/zram/zcomp_lzo.c
@@ -15,7 +15,7 @@
 
 static void *lzo_create(void)
 {
-	return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	return kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO);
 }
 
 static void lzo_destroy(void *private)

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