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Groups > linux.kernel > #1224175

[PATCH 1/3] zram: make max_zpage_size configurable

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It makes sense to have control over what compression ratios are
ok to store pages uncompressed and what not. Moreover, if we end
up using zbud allocator for zram, any attempt to allocate a whole
page will fail, so we may want to avoid this as much as possible.

So, let's have max_zpage_size configurable as a module parameter.

Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
---
 drivers/block/zram/zram_drv.c | 13 +++++++++++++
 drivers/block/zram/zram_drv.h | 16 ----------------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9fa15bb..6d9f1d1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -42,6 +42,7 @@ static const char *default_compressor = "lzo";
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
+static size_t max_zpage_size = PAGE_SIZE / 4 * 3;
 
 static inline void deprecated_attr_warn(const char *name)
 {
@@ -1411,6 +1412,16 @@ static int __init zram_init(void)
 		return ret;
 	}
 
+	/*
+	 * max_zpage_size must be less than or equal to:
+	 * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
+	 * always return failure.
+	 */
+	if (max_zpage_size > PAGE_SIZE) {
+		pr_err("Invalid max_zpage_size %ld\n", max_zpage_size);
+		return -EINVAL;
+	}
+
 	zram_major = register_blkdev(0, "zram");
 	if (zram_major <= 0) {
 		pr_err("Unable to get major number\n");
@@ -1444,6 +1455,8 @@ module_exit(zram_exit);
 
 module_param(num_devices, uint, 0);
 MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
+module_param(max_zpage_size, ulong, 0);
+MODULE_PARM_DESC(max_zpage_size, "Threshold for storing compressed pages");
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 8e92339..3a29c33 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -20,22 +20,6 @@
 
 #include "zcomp.h"
 
-/*-- Configurable parameters */
-
-/*
- * Pages that compress to size greater than this are stored
- * uncompressed in memory.
- */
-static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
-
-/*
- * NOTE: max_zpage_size must be less than or equal to:
- *   ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
- * always return failure.
- */
-
-/*-- End of configurable params */
-
 #define SECTOR_SHIFT		9
 #define SECTORS_PER_PAGE_SHIFT	(PAGE_SHIFT - SECTOR_SHIFT)
 #define SECTORS_PER_PAGE	(1 << SECTORS_PER_PAGE_SHIFT)
-- 
1.9.1
--
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Thread

[PATCH 0/3] allow zram to use zbud as underlying allocator Vitaly Wool <vitalywool@gmail.com> - 2015-09-14 15:50 +0200
  [PATCH 1/3] zram: make max_zpage_size configurable Vitaly Wool <vitalywool@gmail.com> - 2015-09-14 16:00 +0200
    Re: [PATCH 1/3] zram: make max_zpage_size configurable Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 03:10 +0200
      Re: [PATCH 1/3] zram: make max_zpage_size configurable Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 09:40 +0200
    Re: [PATCH 1/3] zram: make max_zpage_size configurable Dan Streetman <ddstreet@ieee.org> - 2015-09-15 07:50 +0200
      Re: [PATCH 1/3] zram: make max_zpage_size configurable Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 08:10 +0200
  [PATCH 3/3] zram: use common zpool interface Vitaly Wool <vitalywool@gmail.com> - 2015-09-14 16:00 +0200
    Re: [PATCH 3/3] zram: use common zpool interface Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 03:20 +0200
      Re: [PATCH 3/3] zram: use common zpool interface Dan Streetman <ddstreet@ieee.org> - 2015-09-15 08:10 +0200
  [PATCH 2/3] zpool/zsmalloc/zbud: align on interfaces Vitaly Wool <vitalywool@gmail.com> - 2015-09-14 16:00 +0200
    Re: [PATCH 2/3] zpool/zsmalloc/zbud: align on interfaces Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 03:10 +0200
      Re: [PATCH 2/3] zpool/zsmalloc/zbud: align on interfaces Dan Streetman <ddstreet@ieee.org> - 2015-09-15 07:10 +0200
  Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Vlastimil Babka <vbabka@suse.cz> - 2015-09-14 16:10 +0200
    Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Vlastimil Babka <vbabka@suse.cz> - 2015-09-14 16:20 +0200
      Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Dan Streetman <ddstreet@ieee.org> - 2015-09-15 06:10 +0200
        Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 06:30 +0200
          Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Vlastimil Babka <vbabka@suse.cz> - 2015-09-17 08:30 +0200
            Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-09-17 11:30 +0200
    Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Vitaly Wool <vitalywool@gmail.com> - 2015-09-14 16:20 +0200
  Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-15 02:50 +0200
  Re: [PATCH 0/3] allow zram to use zbud as underlying allocator Minchan Kim <minchan@kernel.org> - 2015-09-15 08:20 +0200

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