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Message-Id: <1407977877-18185-2-git-send-email-minchan@kernel.org> Date: Thu, 14 Aug 2014 09:57:57 +0900 From: Minchan Kim <minchan@...nel.org> To: Andrew Morton <akpm@...ux-foundation.org> Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, Sergey Senozhatsky <sergey.senozhatsky@...il.com>, Jerome Marchand <jmarchan@...hat.com>, juno.choi@....com, seungho1.park@....com, Luigi Semenzato <semenzato@...gle.com>, Nitin Gupta <ngupta@...are.org>, Seth Jennings <sjenning@...ux.vnet.ibm.com>, Dan Streetman <ddstreet@...e.org>, ds2horner@...il.com, Minchan Kim <minchan@...nel.org> Subject: [PATCH 2/2] zram: limit memory size for zram Since zram has no control feature to limit memory usage, it makes hard to manage system memrory. This patch adds new knob "mem_limit" via sysfs to set up the limit. Note: I added the logic in zram, not zsmalloc because the limit is requirement of zram, not zsmalloc so I'd like to avoid unnecessary branch in zsmalloc. Signed-off-by: Minchan Kim <minchan@...nel.org> --- Documentation/blockdev/zram.txt | 20 +++++++++++++++---- drivers/block/zram/zram_drv.c | 43 +++++++++++++++++++++++++++++++++++++++++ drivers/block/zram/zram_drv.h | 1 + 3 files changed, 60 insertions(+), 4 deletions(-) diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 0595c3f56ccf..9f239ff8c444 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -74,14 +74,26 @@ There is little point creating a zram of greater than twice the size of memory since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the size of the disk when not in use so a huge zram is wasteful. -5) Activate: +5) Set memory limit: Optional + Set memory limit by writing the value to sysfs node 'mem_limit'. + The value can be either in bytes or you can use mem suffixes. + Examples: + # limit /dev/zram0 with 50MB memory + echo $((50*1024*1024)) > /sys/block/zram0/mem_limit + + # Using mem suffixes + echo 256K > /sys/block/zram0/mem_limit + echo 512M > /sys/block/zram0/mem_limit + echo 1G > /sys/block/zram0/mem_limit + +6) Activate: mkswap /dev/zram0 swapon /dev/zram0 mkfs.ext4 /dev/zram1 mount /dev/zram1 /tmp -6) Stats: +7) Stats: Per-device statistics are exported as various nodes under /sys/block/zram<id>/ disksize @@ -96,11 +108,11 @@ size of the disk when not in use so a huge zram is wasteful. compr_data_size mem_used_total -7) Deactivate: +8) Deactivate: swapoff /dev/zram0 umount /dev/zram1 -8) Reset: +9) Reset: Write any positive value to 'reset' sysfs node echo 1 > /sys/block/zram0/reset echo 1 > /sys/block/zram1/reset diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index d00831c3d731..b48a3d0e9031 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -122,6 +122,35 @@ static ssize_t max_comp_streams_show(struct device *dev, return scnprintf(buf, PAGE_SIZE, "%d\n", val); } +static ssize_t mem_limit_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + u64 val; + struct zram *zram = dev_to_zram(dev); + + down_read(&zram->init_lock); + val = zram->limit_bytes; + up_read(&zram->init_lock); + + return scnprintf(buf, PAGE_SIZE, "%llu\n", val); +} + +static ssize_t mem_limit_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + u64 limit; + struct zram *zram = dev_to_zram(dev); + + limit = memparse(buf, NULL); + if (!limit) + return -EINVAL; + + down_write(&zram->init_lock); + zram->limit_bytes = limit; + up_write(&zram->init_lock); + return len; +} + static ssize_t max_comp_streams_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { @@ -513,6 +542,14 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, ret = -ENOMEM; goto out; } + + if (zram->limit_bytes && + zs_get_total_size_bytes(meta->mem_pool) > zram->limit_bytes) { + zs_free(meta->mem_pool, handle); + ret = -ENOMEM; + goto out; + } + cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { @@ -617,6 +654,9 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity) struct zram_meta *meta; down_write(&zram->init_lock); + + zram->limit_bytes = 0; + if (!init_done(zram)) { up_write(&zram->init_lock); return; @@ -857,6 +897,8 @@ static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL); static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store); static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); +static DEVICE_ATTR(mem_limit, S_IRUGO | S_IWUSR, mem_limit_show, + mem_limit_store); static DEVICE_ATTR(max_comp_streams, S_IRUGO | S_IWUSR, max_comp_streams_show, max_comp_streams_store); static DEVICE_ATTR(comp_algorithm, S_IRUGO | S_IWUSR, @@ -885,6 +927,7 @@ static struct attribute *zram_disk_attrs[] = { &dev_attr_orig_data_size.attr, &dev_attr_compr_data_size.attr, &dev_attr_mem_used_total.attr, + &dev_attr_mem_limit.attr, &dev_attr_max_comp_streams.attr, &dev_attr_comp_algorithm.attr, NULL, diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index e0f725c87cc6..086c51782e75 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -110,6 +110,7 @@ struct zram { * we can store in a disk. */ u64 disksize; /* bytes */ + u64 limit_bytes; int max_comp_streams; struct zram_stats stats; char compressor[10]; -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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