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Date: Thu, 17 Jul 2014 13:27:03 +0300 From: Timofey Titovets <nefelim4ag@...il.com> To: Jerome Marchand <jmarchan@...hat.com>, minchan@...nel.org CC: Sergey Senozhatsky <sergey.senozhatsky@...il.com>, linux-kernel@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org>, Nitin Gupta <ngupta@...are.org> Subject: Re: [PATCH] zram: auto add/del devices on demand Thanks for comments, i will fix what you say and split patches one for code and one for Documentation. After, i will resend patch set On 07/17/2014 01:09 PM, Jerome Marchand wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 07/17/2014 11:32 AM, Timofey Titovets wrote: >> From: Timofey Titovets <nefelim4ag@...il.com> >> >> 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 <nefelim4ag@...il.com> >> >> 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 >> <ngupta@...are.org>"); > > -----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@...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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