From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com [209.85.212.176]) by kanga.kvack.org (Postfix) with ESMTP id A40206B0038 for ; Thu, 21 Aug 2014 15:08:34 -0400 (EDT) Received: by mail-wi0-f176.google.com with SMTP id bs8so9181761wib.15 for ; Thu, 21 Aug 2014 12:08:34 -0700 (PDT) Received: from mail-we0-x234.google.com (mail-we0-x234.google.com [2a00:1450:400c:c03::234]) by mx.google.com with ESMTPS id ew2si42360866wjd.41.2014.08.21.12.08.32 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 21 Aug 2014 12:08:33 -0700 (PDT) Received: by mail-we0-f180.google.com with SMTP id w61so9698736wes.25 for ; Thu, 21 Aug 2014 12:08:32 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1408580838-29236-4-git-send-email-minchan@kernel.org> References: <1408580838-29236-1-git-send-email-minchan@kernel.org> <1408580838-29236-4-git-send-email-minchan@kernel.org> From: Dan Streetman Date: Thu, 21 Aug 2014 15:08:12 -0400 Message-ID: Subject: Re: [PATCH v3 3/4] zram: zram memory size limitation Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , Linux-MM , linux-kernel , Sergey Senozhatsky , Jerome Marchand , juno.choi@lge.com, seungho1.park@lge.com, Luigi Semenzato , Nitin Gupta , Seth Jennings , David Horner On Wed, Aug 20, 2014 at 8:27 PM, Minchan Kim wrote: > 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 > a limit so that zram could fail allocation once it reaches > the limit. > > Signed-off-by: Minchan Kim > --- > Documentation/ABI/testing/sysfs-block-zram | 9 +++++++ > Documentation/blockdev/zram.txt | 20 ++++++++++++--- > drivers/block/zram/zram_drv.c | 41 ++++++++++++++++++++++++++++++ > drivers/block/zram/zram_drv.h | 5 ++++ > 4 files changed, 71 insertions(+), 4 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram > index 70ec992514d0..025331c19045 100644 > --- a/Documentation/ABI/testing/sysfs-block-zram > +++ b/Documentation/ABI/testing/sysfs-block-zram > @@ -119,3 +119,12 @@ Description: > efficiency can be calculated using compr_data_size and this > statistic. > Unit: bytes > + > +What: /sys/block/zram/mem_limit > +Date: August 2014 > +Contact: Minchan Kim > +Description: > + The mem_limit file is read/write and specifies the amount > + of memory to be able to consume memory to store store > + compressed data. might want to clarify here that the value "0", which is the default, disables the limit. > + Unit: bytes > 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 # To disable memory limit echo 0 > /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/ > 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 302dd37bcea3..adc91c7ecaef 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -122,6 +122,33 @@ 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_pages; > + up_read(&zram->init_lock); > + > + return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT); > +} > + > +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); > + down_write(&zram->init_lock); > + zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT; > + 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 +540,14 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, > ret = -ENOMEM; > goto out; > } > + > + if (zram->limit_pages && > + zs_get_total_size(meta->mem_pool) > zram->limit_pages) { > + 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 +652,9 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity) > struct zram_meta *meta; > > down_write(&zram->init_lock); > + > + zram->limit_pages = 0; > + > if (!init_done(zram)) { > up_write(&zram->init_lock); > return; > @@ -857,6 +895,8 @@ 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 +925,7 @@ 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..b7aa9c21553f 100644 > --- a/drivers/block/zram/zram_drv.h > +++ b/drivers/block/zram/zram_drv.h > @@ -112,6 +112,11 @@ struct zram { > u64 disksize; /* bytes */ > int max_comp_streams; > struct zram_stats stats; > + /* > + * the number of pages zram can consume for storing compressed data > + */ > + unsigned long limit_pages; > + > char compressor[10]; > }; > #endif > -- > 2.0.0 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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