On Thu, Mar 16, 2017 at 11:46:38AM +0900, [email protected] wrote: > From: Joonsoo Kim <[email protected]> > > Benefit of deduplication is dependent on the workload so it's not > preferable to always enable. Therefore, make it optional.
Please make it to Kconfig, too. And write down the description to impress "help a lot for users who uses zram to build output directory" And the feature should be disabled as default. > > Signed-off-by: Joonsoo Kim <[email protected]> > --- > drivers/block/zram/zram_drv.c | 80 > ++++++++++++++++++++++++++++++++++++++----- > drivers/block/zram/zram_drv.h | 1 + > 2 files changed, 73 insertions(+), 8 deletions(-) > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 012425f..e45aa9f 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -328,6 +328,39 @@ static ssize_t comp_algorithm_store(struct device *dev, > return len; > } > > +static ssize_t use_dedup_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + int val; > + struct zram *zram = dev_to_zram(dev); > + > + down_read(&zram->init_lock); > + val = zram->use_dedup; > + up_read(&zram->init_lock); > + > + return scnprintf(buf, PAGE_SIZE, "%d\n", val); > +} > + > +static ssize_t use_dedup_store(struct device *dev, > + struct device_attribute *attr, const char *buf, size_t len) > +{ > + int val; > + struct zram *zram = dev_to_zram(dev); > + > + if (kstrtoint(buf, 10, &val) || (val != 0 && val != 1)) > + return -EINVAL; > + > + down_write(&zram->init_lock); > + if (init_done(zram)) { > + up_write(&zram->init_lock); > + pr_info("Can't change dedup usage for initialized device\n"); > + return -EBUSY; > + } > + zram->use_dedup = val; > + up_write(&zram->init_lock); > + return len; > +} > + > static ssize_t compact_store(struct device *dev, > struct device_attribute *attr, const char *buf, size_t len) > { > @@ -422,11 +455,23 @@ static ssize_t debug_stat_show(struct device *dev, > static DEVICE_ATTR_RO(mm_stat); > static DEVICE_ATTR_RO(debug_stat); > > -static u32 zram_calc_checksum(unsigned char *mem) > +static u32 zram_calc_checksum(struct zram *zram, unsigned char *mem) > { > + if (!zram->use_dedup) > + return 0; > + Hmm, I don't like this style which every dedup functions have the check "use_dedup". Can't we abstract like this? I want to find more simple way to no need to add the check when new dedup functions pop up. bool zram_dedup_check if (!zram->dedup) return false; zram_dedup_checksum entry = zram_dedup_get if (!entry) { zram_dedup_add return false; } .. return true; zram_bvec_write: ... ... if (zram_dedup_match()) goto found_dup; > return jhash(mem, PAGE_SIZE, 0); > } > > +static unsigned long zram_entry_handle(struct zram *zram, > + struct zram_entry *entry) > +{ > + if (!zram->use_dedup) > + return (unsigned long)entry; > + > + return entry->handle; > +} > + > static struct zram_entry *zram_entry_alloc(struct zram *zram, > unsigned int len, gfp_t flags) > { > @@ -438,6 +483,9 @@ static struct zram_entry *zram_entry_alloc(struct zram > *zram, > if (!handle) > return NULL; > > + if (!zram->use_dedup) > + return (struct zram_entry *)handle; > + > entry = kzalloc(sizeof(*entry), flags); > if (!entry) { > zs_free(meta->mem_pool, handle); > @@ -462,6 +510,9 @@ static void zram_entry_insert(struct zram *zram, struct > zram_entry *new, > struct rb_node **rb_node, *parent = NULL; > struct zram_entry *entry; > > + if (!zram->use_dedup) > + return; > + > new->checksum = checksum; > hash = &meta->hash[checksum % meta->hash_size]; > rb_root = &hash->rb_root; > @@ -492,7 +543,8 @@ static bool zram_entry_match(struct zram *zram, struct > zram_entry *entry, > struct zram_meta *meta = zram->meta; > struct zcomp_strm *zstrm; > > - cmem = zs_map_object(meta->mem_pool, entry->handle, ZS_MM_RO); > + cmem = zs_map_object(meta->mem_pool, > + zram_entry_handle(zram, entry), ZS_MM_RO); > if (entry->len == PAGE_SIZE) { > match = !memcmp(mem, cmem, PAGE_SIZE); > } else { > @@ -501,7 +553,7 @@ static bool zram_entry_match(struct zram *zram, struct > zram_entry *entry, > match = !memcmp(mem, zstrm->buffer, PAGE_SIZE); > zcomp_stream_put(zram->comp); > } > - zs_unmap_object(meta->mem_pool, entry->handle); > + zs_unmap_object(meta->mem_pool, zram_entry_handle(zram, entry)); > > return match; > } > @@ -521,6 +573,11 @@ static bool zram_entry_put(struct zram *zram, struct > zram_meta *meta, > struct zram_hash *hash; > u32 checksum; > > + if (!zram->use_dedup) { > + zs_free(meta->mem_pool, zram_entry_handle(zram, entry)); > + return false; > + } > + > if (!populated) > goto free; > > @@ -551,6 +608,9 @@ static struct zram_entry *zram_entry_get(struct zram > *zram, > struct zram_entry *entry; > struct rb_node *rb_node; > > + if (!zram->use_dedup) > + return NULL; > + > hash = &meta->hash[checksum % meta->hash_size]; > > spin_lock(&hash->lock); > @@ -713,7 +773,8 @@ static int zram_decompress_page(struct zram *zram, char > *mem, u32 index) > return 0; > } > > - cmem = zs_map_object(meta->mem_pool, entry->handle, ZS_MM_RO); > + cmem = zs_map_object(meta->mem_pool, > + zram_entry_handle(zram, entry), ZS_MM_RO); > if (size == PAGE_SIZE) { > copy_page(mem, cmem); > } else { > @@ -722,7 +783,7 @@ static int zram_decompress_page(struct zram *zram, char > *mem, u32 index) > ret = zcomp_decompress(zstrm, cmem, size, mem); > zcomp_stream_put(zram->comp); > } > - zs_unmap_object(meta->mem_pool, entry->handle); > + zs_unmap_object(meta->mem_pool, zram_entry_handle(zram, entry)); > bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); > > /* Should NEVER happen. Return bio error if it does. */ > @@ -840,7 +901,7 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > goto out; > } > > - checksum = zram_calc_checksum(uncmem); > + checksum = zram_calc_checksum(zram, uncmem); > if (!entry) { > entry = zram_entry_get(zram, uncmem, checksum); > if (entry) { > @@ -915,7 +976,8 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > goto out; > } > > - cmem = zs_map_object(meta->mem_pool, entry->handle, ZS_MM_WO); > + cmem = zs_map_object(meta->mem_pool, > + zram_entry_handle(zram, entry), ZS_MM_WO); > > if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { > src = kmap_atomic(page); > @@ -927,7 +989,7 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > > zcomp_stream_put(zram->comp); > zstrm = NULL; > - zs_unmap_object(meta->mem_pool, entry->handle); > + zs_unmap_object(meta->mem_pool, zram_entry_handle(zram, entry)); > zram_entry_insert(zram, entry, checksum); > > found_duplication: > @@ -1310,6 +1372,7 @@ static int zram_open(struct block_device *bdev, fmode_t > mode) > static DEVICE_ATTR_WO(mem_used_max); > static DEVICE_ATTR_RW(max_comp_streams); > static DEVICE_ATTR_RW(comp_algorithm); > +static DEVICE_ATTR_RW(use_dedup); > > static struct attribute *zram_disk_attrs[] = { > &dev_attr_disksize.attr, > @@ -1320,6 +1383,7 @@ static int zram_open(struct block_device *bdev, fmode_t > mode) > &dev_attr_mem_used_max.attr, > &dev_attr_max_comp_streams.attr, > &dev_attr_comp_algorithm.attr, > + &dev_attr_use_dedup.attr, > &dev_attr_io_stat.attr, > &dev_attr_mm_stat.attr, > &dev_attr_debug_stat.attr, > diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h > index 07d1f8d..b823555 100644 > --- a/drivers/block/zram/zram_drv.h > +++ b/drivers/block/zram/zram_drv.h > @@ -141,5 +141,6 @@ struct zram { > * zram is claimed so open request will be failed > */ > bool claim; /* Protected by bdev->bd_mutex */ > + int use_dedup; For binary result, I want to use 'bool' > }; > #endif > -- > 1.9.1 >
