Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932240AbaGQKJ4 (ORCPT ); Thu, 17 Jul 2014 06:09:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26516 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753994AbaGQKJy (ORCPT ); Thu, 17 Jul 2014 06:09:54 -0400 Message-ID: <53C7A0C1.60600@redhat.com> Date: Thu, 17 Jul 2014 12:09:05 +0200 From: Jerome Marchand User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Timofey Titovets , minchan@kernel.org CC: Sergey Senozhatsky , linux-kernel@vger.kernel.org, Andrew Morton , Nitin Gupta Subject: Re: [PATCH] zram: auto add/del devices on demand References: <53C7982F.8020205@gmail.com> In-Reply-To: <53C7982F.8020205@gmail.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/17/2014 11:32 AM, Timofey Titovets wrote: > From: Timofey Titovets > > This add supporting of autochange count of zram devices on demand, > like loop devices; This working by following rules: - Always save > minimum devices count specified by num_device (can be specified > while kernel module loading) - if last device already using add new > device; - if last and prelast devices is free - delete last zram > device; > Hi Timofey, Your patch change zram behaviour. Please describe what changes from the user point of view and update Documentation/blockdev/zram.txt accordingly. > Signed-off-by: Timofey Titovets > > Please pull from: https://github.com/Nefelim4ag/linux.git --- > Tested on 3.15.5-2-ARCH, can be applied on any kernel version after > this patch 'zram: add LZ4 compression support' - > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=6e76668e415adf799839f0ab205142ad7002d260 > > --- drivers/block/zram/zram_drv.c | 65 > ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 61 > insertions(+), 4 deletions(-) > > diff --git a/drivers/block/zram/zram_drv.c > b/drivers/block/zram/zram_drv.c index 089e72c..d0a3055 100644 --- > a/drivers/block/zram/zram_drv.c +++ > b/drivers/block/zram/zram_drv.c @@ -42,6 +42,10 @@ static const > char *default_compressor = "lzo"; > > /* Module params (documentation at end) */ static unsigned int > num_devices = 1; +static unsigned int last_created_dev = 1; + > +static void zram_add_dev(void); +static void zram_del_dev(void); > > #define ZRAM_ATTR_RO(name) \ static ssize_t > zram_attr_##name##_show(struct device *d, \ @@ -168,6 +172,7 > @@ static ssize_t comp_algorithm_store(struct device *dev, struct > device_attribute *attr, const char *buf, size_t len) { struct zram > *zram = dev_to_zram(dev); + down_write(&zram->init_lock); if > (init_done(zram)) { up_write(&zram->init_lock); @@ -239,6 +244,7 @@ > static struct zram_meta *zram_meta_alloc(u64 disksize) { size_t > num_pages; struct zram_meta *meta = kmalloc(sizeof(*meta), > GFP_KERNEL); + if (!meta) goto out; > > @@ -374,6 +380,7 @@ static int zram_bvec_read(struct zram *zram, > struct bio_vec *bvec, struct page *page; unsigned char *user_mem, > *uncmem = NULL; struct zram_meta *meta = zram->meta; + page = > bvec->bv_page; > > read_lock(&meta->tb_lock); @@ -607,6 +614,7 @@ static void > zram_reset_device(struct zram *zram, bool reset_capacity) /* Free > all pages that are still in this zram device */ for (index = 0; > index < zram->disksize >> PAGE_SHIFT; index++) { unsigned long > handle = meta->table[index].handle; + if (!handle) continue; > > @@ -668,6 +676,7 @@ static ssize_t disksize_store(struct device > *dev, set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); > revalidate_disk(zram->disk); up_write(&zram->init_lock); + > zram_add_dev(); return len; > > out_destroy_comp: @@ -712,6 +721,7 @@ static ssize_t > reset_store(struct device *dev, bdput(bdev); > > zram_reset_device(zram, true); + zram_del_dev(); return len; > > out: @@ -954,6 +964,51 @@ static void destroy_device(struct zram > *zram) blk_cleanup_queue(zram->queue); } > > +/* remove last free device, if last and prelast dev a free */ > +static void zram_del_dev(void) +{ + if (last_created_dev < > num_devices) + return; + + if > (zram_devices[last_created_dev].disksize == 0 && + > zram_devices[last_created_dev-1].disksize == 0 + ) { + > destroy_device(&zram_devices[last_created_dev]); + > last_created_dev--; + pr_info("Deleted zram%u device\n", > last_created_dev); + } +} + +/* Auto add empty zram device, if > last device in use */ +static void zram_add_dev(void) +{ + int > ret; + + if (last_created_dev+1 > max_num_devices) { + > pr_warn("Can't add zram%u, max device number reached\n", + > num_devices); + last_created_dev--; + ret = -EINVAL; Why do you set ret to EINVAL here? It's never used. > + goto out; That label is useless. Just use return. > + } + + if (&zram_devices[last_created_dev].disksize > 0) { + > last_created_dev++; + ret = > create_device(&zram_devices[last_created_dev], + > last_created_dev); + if (ret) + goto free; If ret is only used to test that create_device() succeeded, then we can get rid of that variable altogether. Thanks, Jerome > + pr_info("Created zram%u device\n", last_created_dev); + > } + + return; + +free: + > destroy_device(&zram_devices[last_created_dev]); + > last_created_dev--; +out:; +} + static int __init zram_init(void) > { int ret, dev_id; @@ -972,18 +1027,20 @@ static int __init > zram_init(void) goto out; } > > - /* Allocate the device array and initialize each one */ - > zram_devices = kzalloc(num_devices * sizeof(struct zram), > GFP_KERNEL); + /* Allocate the device array */ + zram_devices > = kcalloc(max_num_devices, sizeof(struct zram), GFP_KERNEL); if > (!zram_devices) { ret = -ENOMEM; goto unregister; } > > + /* Initialise zram{0..num_devices} */ for (dev_id = 0; dev_id > < num_devices; dev_id++) { ret = > create_device(&zram_devices[dev_id], dev_id); if (ret) goto > free_devices; } + last_created_dev = num_devices-1; > > pr_info("Created %u device(s) ...\n", num_devices); > > @@ -1004,7 +1061,7 @@ static void __exit zram_exit(void) int i; > struct zram *zram; > > - for (i = 0; i < num_devices; i++) { + for (i = 0; i < > last_created_dev+1; i++) { zram = &zram_devices[i]; > > destroy_device(zram); @@ -1025,7 +1082,7 @@ > module_init(zram_init); module_exit(zram_exit); > > module_param(num_devices, uint, 0); -MODULE_PARM_DESC(num_devices, > "Number of zram devices"); +MODULE_PARM_DESC(num_devices, "Number > of pre created zram devices"); > > MODULE_LICENSE("Dual BSD/GPL"); MODULE_AUTHOR("Nitin Gupta > "); -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTx6C9AAoJEHTzHJCtsuoC+VIH/R7Z1rQ7iNhsa5ycEIJFdxsa tp3oihmg3tvdnTlXj4bBb57zyN8fV2t/pfUOHFn3BWWm8lmruE43T25E5C+HuB7H VSAD8lxBHCO+NrA+imHtnReHdN22VwrJFUR9ZQfKzSj+GruoJQZVXD9NHhf9oI0q TMgfHK1klnS5ZQ8y1Qq3fllFk/89XSCMAF3ySymWRzm4zcyKIiYLVm2xtou9cYCG DF6JrwUtnr3swQrbTqwUPLVKIdtDfrDSBCdz0vEZ8gFtCB8vVTzF0CqUhkjaxt83 cldz0FfLM31iZ+l+5MVvTHIVl4a2oC+lZ4EAfX3qZBGK1HA/V0obLjgCLTZwS2s= =JJII -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/