Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752654AbaAPJmz (ORCPT ); Thu, 16 Jan 2014 04:42:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52887 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752567AbaAPJmo (ORCPT ); Thu, 16 Jan 2014 04:42:44 -0500 Message-ID: <52D7A952.3050907@redhat.com> Date: Thu, 16 Jan 2014 10:41:38 +0100 From: Jerome Marchand User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Sergey Senozhatsky CC: Minchan Kim , Andrew Morton , Nitin Gupta , linux-kernel@vger.kernel.org Subject: Re: [PATCHv2 3/4] zram: rework reported to end-user zram statistics References: <1389780977-18949-1-git-send-email-sergey.senozhatsky@gmail.com> <1389780977-18949-4-git-send-email-sergey.senozhatsky@gmail.com> <20140116005645.GM1992@bbox> <20140116084638.GA2122@swordfish> In-Reply-To: <20140116084638.GA2122@swordfish> 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 On 01/16/2014 09:46 AM, Sergey Senozhatsky wrote: > On (01/16/14 09:56), Minchan Kim wrote: >> Hello Sergey, >> >> On Wed, Jan 15, 2014 at 01:16:16PM +0300, Sergey Senozhatsky wrote: >>> 1) Introduce ZRAM_ATTR_RO macro to generate zram atomic64_t stats >>> `show' functions and reduce code duplication. >>> >>> 2) Remove `good' and `bad' compressed sub-requests stats. RW request may >>> cause a number of RW sub-requests. zram used to account `good' compressed >>> sub-queries (with compressed size less than 50% of original size), `bad' >>> compressed sub-queries (with compressed size greater that 75% of original >>> size), leaving sub-requests with compression size between 50% and 75% of >>> original size not accounted and not reported. zram already accounts each >>> sub-request's compression size so we can calculate real device compression >>> ratio. >>> >>> Acked-by: Minchan Kim >> >> I didn't give any Acked in this patch. >> If I made you confused, Sorry about that. >> > > Hello, > > sorry, I misread the situtation. Now that Minchan draw my attention to it: neither did I. > >> This patch did more than thing you mentioned in desription. >> >> 1. Introduce macro to remove code duplication >> >> It's really good. No argument here. >> >> 2. Change atomic_t with atomic64_t >> >> At a first look, I didn't want it because lots of custormer for zram >> are still 32bit machines so their cost would be increased a bit due to >> any locking facility like cmpxchg on some architectures. >> >> Having said that, I will support your cleanup patch now and then >> If we really have trouble with atomic stat operation, we could >> change it with percpu_counter so that it could solve atomic overhead and >> unnecessary memory space by introducing unsigned long instead of 64bit >> atomic_t. >> >> So, please add this comment for future just in case of forgetting. > > ok > >> 3. Remove unreported some stat >> >> Looks good to me. To me too. >> > >> 4. Changing name of some stat >> >> I couldn't understand what's the gain because I'm happy with >> orig_data_size and compr_data_size now. >> > > well, compressed_size contains regular english words and thus a regular > user can easily understand it. compr_data_size looks like a variable name. > I think I'll drop this at the moment. I think that anybody who is going to read this stats will know that zram is about compression and understand these abbreviations. I also like the fact that they are both expressed in bytes, unlike the couple pages_store / compressed_size. > >> 5. Removed zram_init_device's warning >> >> Why? This patch doesn't include any justification. >> > > I think I'll drop this part at the moment. the motivation for this > cleanup was that, imho, such big informative warnings are part of > documentation, not the source code. Yet you didn't update the documentation. Jerome > > -ss > >> 6. Removed unused field of enum zram_pageflags >> >> Looks good to me. >> >> Please, separate it with each patches so let's focus one by one. >> >> >>> Acked-by: Jerome Marchand >>> Signed-off-by: Sergey Senozhatsky >>> --- >>> drivers/block/zram/zram_drv.c | 163 ++++++++++++------------------------------ >>> drivers/block/zram/zram_drv.h | 17 ++--- >>> 2 files changed, 51 insertions(+), 129 deletions(-) >>> >>> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c >>> index b0bcb7e..6eb2155 100644 >>> --- a/drivers/block/zram/zram_drv.c >>> +++ b/drivers/block/zram/zram_drv.c >>> @@ -42,6 +42,17 @@ static struct zram *zram_devices; >>> /* Module params (documentation at end) */ >>> static unsigned int num_devices = 1; >>> >>> +#define ZRAM_ATTR_RO(name) \ >>> +static ssize_t zram_attr_##name##_show(struct device *d, \ >>> + struct device_attribute *attr, char *b) \ >>> +{ \ >>> + struct zram *zram = dev_to_zram(d); \ >>> + return sprintf(b, "%llu\n", \ >>> + (u64)atomic64_read(&zram->stats.name)); \ >>> +} \ >>> +static struct device_attribute dev_attr_##name = \ >>> + __ATTR(name, S_IRUGO, zram_attr_##name##_show, NULL); >>> + >>> static inline int init_done(struct zram *zram) >>> { >>> return zram->meta != NULL; >>> @@ -52,97 +63,36 @@ static inline struct zram *dev_to_zram(struct device *dev) >>> return (struct zram *)dev_to_disk(dev)->private_data; >>> } >>> >>> -static ssize_t disksize_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", zram->disksize); >>> -} >>> - >>> -static ssize_t initstate_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%u\n", init_done(zram)); >>> -} >>> - >>> -static ssize_t num_reads_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", >>> - (u64)atomic64_read(&zram->stats.num_reads)); >>> -} >>> - >>> -static ssize_t num_writes_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", >>> - (u64)atomic64_read(&zram->stats.num_writes)); >>> -} >>> - >>> -static ssize_t invalid_io_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", >>> - (u64)atomic64_read(&zram->stats.invalid_io)); >>> -} >>> - >>> -static ssize_t notify_free_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", >>> - (u64)atomic64_read(&zram->stats.notify_free)); >>> -} >>> - >>> -static ssize_t zero_pages_show(struct device *dev, >>> - struct device_attribute *attr, char *buf) >>> -{ >>> - struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%u\n", atomic_read(&zram->stats.pages_zero)); >>> -} >>> - >>> -static ssize_t orig_data_size_show(struct device *dev, >>> +static ssize_t memory_used_show(struct device *dev, >>> struct device_attribute *attr, char *buf) >>> { >>> + u64 val = 0; >>> struct zram *zram = dev_to_zram(dev); >>> + struct zram_meta *meta = zram->meta; >>> >>> - return sprintf(buf, "%llu\n", >>> - (u64)(atomic_read(&zram->stats.pages_stored)) << PAGE_SHIFT); >>> + down_read(&zram->init_lock); >>> + if (init_done(zram)) >>> + val = zs_get_total_size_bytes(meta->mem_pool); >>> + up_read(&zram->init_lock); >>> + return sprintf(buf, "%llu\n", val); >>> } >>> >>> -static ssize_t compr_data_size_show(struct device *dev, >>> +static ssize_t disksize_show(struct device *dev, >>> struct device_attribute *attr, char *buf) >>> { >>> struct zram *zram = dev_to_zram(dev); >>> - >>> - return sprintf(buf, "%llu\n", >>> - (u64)atomic64_read(&zram->stats.compr_size)); >>> + return sprintf(buf, "%llu\n", zram->disksize); >>> } >>> >>> -static ssize_t mem_used_total_show(struct device *dev, >>> +static ssize_t initstate_show(struct device *dev, >>> struct device_attribute *attr, char *buf) >>> { >>> - u64 val = 0; >>> + u32 val = 0; >>> struct zram *zram = dev_to_zram(dev); >>> - struct zram_meta *meta = zram->meta; >>> - >>> down_read(&zram->init_lock); >>> - if (init_done(zram)) >>> - val = zs_get_total_size_bytes(meta->mem_pool); >>> + val = init_done(zram); >>> up_read(&zram->init_lock); >>> - >>> - return sprintf(buf, "%llu\n", val); >>> + return sprintf(buf, "%u\n", val); >>> } >>> >>> /* flag operations needs meta->tb_lock */ >>> @@ -293,7 +243,6 @@ static void zram_free_page(struct zram *zram, size_t index) >>> { >>> struct zram_meta *meta = zram->meta; >>> unsigned long handle = meta->table[index].handle; >>> - u16 size = meta->table[index].size; >>> >>> if (unlikely(!handle)) { >>> /* >>> @@ -302,21 +251,15 @@ static void zram_free_page(struct zram *zram, size_t index) >>> */ >>> if (zram_test_flag(meta, index, ZRAM_ZERO)) { >>> zram_clear_flag(meta, index, ZRAM_ZERO); >>> - atomic_dec(&zram->stats.pages_zero); >>> + atomic64_dec(&zram->stats.pages_zero); >>> } >>> return; >>> } >>> >>> - if (unlikely(size > max_zpage_size)) >>> - atomic_dec(&zram->stats.bad_compress); >>> - >>> zs_free(meta->mem_pool, handle); >>> >>> - if (size <= PAGE_SIZE / 2) >>> - atomic_dec(&zram->stats.good_compress); >>> - >>> - atomic64_sub(meta->table[index].size, &zram->stats.compr_size); >>> - atomic_dec(&zram->stats.pages_stored); >>> + atomic64_sub(meta->table[index].size, &zram->stats.compressed_size); >>> + atomic64_dec(&zram->stats.pages_stored); >>> >>> meta->table[index].handle = 0; >>> meta->table[index].size = 0; >>> @@ -459,7 +402,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, >>> zram_set_flag(meta, index, ZRAM_ZERO); >>> write_unlock(&zram->meta->tb_lock); >>> >>> - atomic_inc(&zram->stats.pages_zero); >>> + atomic64_inc(&zram->stats.pages_zero); >>> ret = 0; >>> goto out; >>> } >>> @@ -478,7 +421,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, >>> } >>> >>> if (unlikely(clen > max_zpage_size)) { >>> - atomic_inc(&zram->stats.bad_compress); >>> clen = PAGE_SIZE; >>> src = NULL; >>> if (is_partial_io(bvec)) >>> @@ -516,11 +458,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, >>> write_unlock(&zram->meta->tb_lock); >>> >>> /* Update stats */ >>> - atomic64_add(clen, &zram->stats.compr_size); >>> - atomic_inc(&zram->stats.pages_stored); >>> - if (clen <= PAGE_SIZE / 2) >>> - atomic_inc(&zram->stats.good_compress); >>> - >>> + atomic64_add(clen, &zram->stats.compressed_size); >>> + atomic64_inc(&zram->stats.pages_stored); >>> out: >>> if (locked) >>> mutex_unlock(&meta->buffer_lock); >>> @@ -583,23 +522,8 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity) >>> >>> static void zram_init_device(struct zram *zram, struct zram_meta *meta) >>> { >>> - if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) { >>> - pr_info( >>> - "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.\n" >>> - "\tMemory Size: %lu kB\n" >>> - "\tSize you selected: %llu kB\n" >>> - "Continuing anyway ...\n", >>> - (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10 >>> - ); >>> - } >>> - >>> /* zram devices sort of resembles non-rotational disks */ >>> queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); >>> - >>> zram->meta = meta; >>> pr_debug("Initialization done!\n"); >>> } >>> @@ -771,14 +695,15 @@ static DEVICE_ATTR(disksize, S_IRUGO | S_IWUSR, >>> disksize_show, disksize_store); >>> static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL); >>> static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store); >>> -static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL); >>> -static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL); >>> -static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL); >>> -static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL); >>> -static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL); >>> -static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); >>> -static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL); >>> -static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); >>> +static DEVICE_ATTR(memory_used, S_IRUGO, memory_used_show, NULL); >>> + >>> +ZRAM_ATTR_RO(num_reads); >>> +ZRAM_ATTR_RO(num_writes); >>> +ZRAM_ATTR_RO(pages_stored); >>> +ZRAM_ATTR_RO(invalid_io); >>> +ZRAM_ATTR_RO(notify_free); >>> +ZRAM_ATTR_RO(pages_zero); >>> +ZRAM_ATTR_RO(compressed_size); >>> >>> static struct attribute *zram_disk_attrs[] = { >>> &dev_attr_disksize.attr, >>> @@ -786,12 +711,12 @@ static struct attribute *zram_disk_attrs[] = { >>> &dev_attr_reset.attr, >>> &dev_attr_num_reads.attr, >>> &dev_attr_num_writes.attr, >>> + &dev_attr_pages_stored.attr, >>> &dev_attr_invalid_io.attr, >>> &dev_attr_notify_free.attr, >>> - &dev_attr_zero_pages.attr, >>> - &dev_attr_orig_data_size.attr, >>> - &dev_attr_compr_data_size.attr, >>> - &dev_attr_mem_used_total.attr, >>> + &dev_attr_pages_zero.attr, >>> + &dev_attr_compressed_size.attr, >>> + &dev_attr_memory_used.attr, >>> NULL, >>> }; >>> >>> diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h >>> index e81e9cd..277023d 100644 >>> --- a/drivers/block/zram/zram_drv.h >>> +++ b/drivers/block/zram/zram_drv.h >>> @@ -64,22 +64,19 @@ enum zram_pageflags { >>> struct table { >>> unsigned long handle; >>> u16 size; /* object size (excluding header) */ >>> - u8 count; /* object ref count (not yet used) */ >>> - u8 flags; >>> + u16 flags; >>> } __aligned(4); >>> >>> struct zram_stats { >>> - atomic64_t compr_size; /* compressed size of pages stored */ >>> - atomic64_t num_reads; /* failed + successful */ >>> - atomic64_t num_writes; /* --do-- */ >>> - atomic64_t failed_reads; /* should NEVER! happen */ >>> + atomic64_t num_writes; /* number of writes */ >>> + atomic64_t num_reads; /* number of reads */ >>> + atomic64_t pages_stored; /* no. of pages currently stored */ >>> + atomic64_t compressed_size; /* compressed size of pages stored */ >>> + atomic64_t pages_zero; /* no. of zero filled pages */ >>> + atomic64_t failed_reads; /* no. of failed reads */ >>> atomic64_t failed_writes; /* can happen when memory is too low */ >>> atomic64_t invalid_io; /* non-page-aligned I/O requests */ >>> atomic64_t notify_free; /* no. of swap slot free notifications */ >>> - atomic_t pages_zero; /* no. of zero filled pages */ >>> - atomic_t pages_stored; /* no. of pages currently stored */ >>> - atomic_t good_compress; /* % of pages with compression ratio<=50% */ >>> - atomic_t bad_compress; /* % of pages with compression ratio>=75% */ >>> }; >>> >>> struct zram_meta { >>> -- >>> 1.8.5.3.493.gb139ac2 >>> >>> -- >>> 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/ >> >> -- >> Kind regards, >> Minchan Kim >> -- 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/