Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751714AbaAPI4i (ORCPT ); Thu, 16 Jan 2014 03:56:38 -0500 Received: from mail-ee0-f43.google.com ([74.125.83.43]:56993 "EHLO mail-ee0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960AbaAPI4g (ORCPT ); Thu, 16 Jan 2014 03:56:36 -0500 Date: Thu, 16 Jan 2014 11:46:38 +0300 From: Sergey Senozhatsky To: Minchan Kim 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: <20140116084638.GA2122@swordfish> References: <1389780977-18949-1-git-send-email-sergey.senozhatsky@gmail.com> <1389780977-18949-4-git-send-email-sergey.senozhatsky@gmail.com> <20140116005645.GM1992@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140116005645.GM1992@bbox> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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. ok > 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. > 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. > 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. -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/