Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752403AbaAPA4R (ORCPT ); Wed, 15 Jan 2014 19:56:17 -0500 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:43875 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752265AbaAPAz4 (ORCPT ); Wed, 15 Jan 2014 19:55:56 -0500 X-AuditID: 9c930197-b7b7cae000000e34-ba-52d72e1ad81d Date: Thu, 16 Jan 2014 09:56:45 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Andrew Morton , Jerome Marchand , Nitin Gupta , linux-kernel@vger.kernel.org Subject: Re: [PATCHv2 3/4] zram: rework reported to end-user zram statistics Message-ID: <20140116005645.GM1992@bbox> References: <1389780977-18949-1-git-send-email-sergey.senozhatsky@gmail.com> <1389780977-18949-4-git-send-email-sergey.senozhatsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389780977-18949-4-git-send-email-sergey.senozhatsky@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. This patch did more than thing you mentioned in desription. 1. Introduce macro to remove code duplication It's really good. 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. 3. Remove unreported some stat Looks good to me. 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. 5. Removed zram_init_device's warning Why? This patch doesn't include any justification. 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/