Re: [PATCH 1/3] zram: make max_zpage_size configurable
From: Sergey Senozhatsky <hidden>
Date: 2015-09-15 00:59:59
Also in:
lkml
On (09/14/15 15:50), Vitaly Wool wrote:
It makes sense to have control over what compression ratios are ok to store pages uncompressed and what not.
um... I don't want this to be exported. this is very 'zram-internal'. besides, you remove the exsiting default value - static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; so now people must provide this module param in order to make zram work the way it used to work for years?
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 how does it help?
quoted hunk ↗ jump to hunk
So, let's have max_zpage_size configurable as a module parameter. Signed-off-by: Vitaly Wool <redacted> --- 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);
and how do people find out ZS_MAX_ALLOC_SIZE? this error message does not help.
quoted hunk ↗ jump to hunk
+ 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");
unclear description.
quoted hunk ↗ jump to hunk
MODULE_LICENSE("Dual BSD/GPL"); MODULE_AUTHOR("Nitin Gupta [off-list ref]");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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
-- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>