From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935060AbdADGXs (ORCPT ); Wed, 4 Jan 2017 01:23:48 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:36295 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932633AbdADGXr (ORCPT ); Wed, 4 Jan 2017 01:23:47 -0500 From: CC: , , , , , , , Subject: [PATCH zram] extend zero pages to same element pages Date: Wed, 4 Jan 2017 14:20:05 +0800 Message-ID: <1483510806-12890-1-git-send-email-zhouxianrong@huawei.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.143.155.56] X-CFilter-Loop: Reflected To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: z00281421 Signed-off-by: z00281421 --- drivers/block/zram/zram_drv.c | 67 ++++++++++++++++++++++++++--------------- drivers/block/zram/zram_drv.h | 11 ++++--- 2 files changed, 49 insertions(+), 29 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 15f58ab..c3af69a 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -94,6 +94,17 @@ static void zram_clear_flag(struct zram_meta *meta, u32 index, meta->table[index].value &= ~BIT(flag); } +static inline void zram_set_element(struct zram_meta *meta, u32 index, + unsigned long element) +{ + meta->table[index].element = element; +} + +static inline void zram_clear_element(struct zram_meta *meta, u32 index) +{ + meta->table[index].element = 0; +} + static size_t zram_get_obj_size(struct zram_meta *meta, u32 index) { return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1); @@ -158,31 +169,31 @@ static inline void update_used_max(struct zram *zram, } while (old_max != cur_max); } -static bool page_zero_filled(void *ptr) +static bool page_same_filled(void *ptr) { unsigned int pos; unsigned long *page; page = (unsigned long *)ptr; - for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { - if (page[pos]) + for (pos = PAGE_SIZE / sizeof(unsigned long) - 1; pos > 0; pos--) { + if (page[pos] != page[pos - 1]) return false; } return true; } -static void handle_zero_page(struct bio_vec *bvec) +static void handle_same_page(struct bio_vec *bvec, unsigned long element) { struct page *page = bvec->bv_page; void *user_mem; user_mem = kmap_atomic(page); if (is_partial_io(bvec)) - memset(user_mem + bvec->bv_offset, 0, bvec->bv_len); + memset(user_mem + bvec->bv_offset, (char)element, bvec->bv_len); else - clear_page(user_mem); + memset(user_mem, (char)element, PAGE_SIZE); kunmap_atomic(user_mem); flush_dcache_page(page); @@ -431,7 +442,7 @@ static ssize_t mm_stat_show(struct device *dev, mem_used << PAGE_SHIFT, zram->limit_pages << PAGE_SHIFT, max_used << PAGE_SHIFT, - (u64)atomic64_read(&zram->stats.zero_pages), + (u64)atomic64_read(&zram->stats.same_pages), pool_stats.pages_compacted); up_read(&zram->init_lock); @@ -464,7 +475,7 @@ static ssize_t debug_stat_show(struct device *dev, ZRAM_ATTR_RO(failed_writes); ZRAM_ATTR_RO(invalid_io); ZRAM_ATTR_RO(notify_free); -ZRAM_ATTR_RO(zero_pages); +ZRAM_ATTR_RO(same_pages); ZRAM_ATTR_RO(compr_data_size); static inline bool zram_meta_get(struct zram *zram) @@ -538,18 +549,20 @@ static void zram_free_page(struct zram *zram, size_t index) struct zram_meta *meta = zram->meta; unsigned long handle = meta->table[index].handle; - if (unlikely(!handle)) { - /* - * No memory is allocated for zero filled pages. - * Simply clear zero page flag. - */ - if (zram_test_flag(meta, index, ZRAM_ZERO)) { - zram_clear_flag(meta, index, ZRAM_ZERO); - atomic64_dec(&zram->stats.zero_pages); - } + /* + * No memory is allocated for same element filled pages. + * Simply clear same page flag. + */ + if (zram_test_flag(meta, index, ZRAM_SAME)) { + zram_clear_flag(meta, index, ZRAM_SAME); + zram_clear_element(meta, index); + atomic64_dec(&zram->stats.same_pages); return; } + if (!handle) + return; + zs_free(meta->mem_pool, handle); atomic64_sub(zram_get_obj_size(meta, index), @@ -572,9 +585,9 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index) handle = meta->table[index].handle; size = zram_get_obj_size(meta, index); - if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { + if (!handle || zram_test_flag(meta, index, ZRAM_SAME)) { bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); - clear_page(mem); + memset(mem, (char)meta->table[index].element, PAGE_SIZE); return 0; } @@ -610,9 +623,9 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); if (unlikely(!meta->table[index].handle) || - zram_test_flag(meta, index, ZRAM_ZERO)) { + zram_test_flag(meta, index, ZRAM_SAME)) { bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); - handle_zero_page(bvec); + handle_same_page(bvec, meta->table[index].element); return 0; } bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); @@ -688,16 +701,20 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, uncmem = user_mem; } - if (page_zero_filled(uncmem)) { + if (page_same_filled(uncmem)) { + unsigned long element; + + element = uncmem[0]; if (user_mem) kunmap_atomic(user_mem); /* Free memory associated with this sector now. */ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); zram_free_page(zram, index); - zram_set_flag(meta, index, ZRAM_ZERO); + zram_set_flag(meta, index, ZRAM_SAME); + zram_set_element(meta, index, element); bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); - atomic64_inc(&zram->stats.zero_pages); + atomic64_inc(&zram->stats.same_pages); ret = 0; goto out; } @@ -1203,7 +1220,7 @@ static int zram_open(struct block_device *bdev, fmode_t mode) &dev_attr_compact.attr, &dev_attr_invalid_io.attr, &dev_attr_notify_free.attr, - &dev_attr_zero_pages.attr, + &dev_attr_same_pages.attr, &dev_attr_orig_data_size.attr, &dev_attr_compr_data_size.attr, &dev_attr_mem_used_total.attr, diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 74fcf10..4bb92e1 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -60,8 +60,8 @@ /* Flags for zram pages (table[page_no].value) */ enum zram_pageflags { - /* Page consists entirely of zeros */ - ZRAM_ZERO = ZRAM_FLAG_SHIFT, + /* Page consists entirely of same elements */ + ZRAM_SAME = ZRAM_FLAG_SHIFT, ZRAM_ACCESS, /* page is now accessed */ __NR_ZRAM_PAGEFLAGS, @@ -71,7 +71,10 @@ enum zram_pageflags { /* Allocated for each disk page */ struct zram_table_entry { - unsigned long handle; + union { + unsigned long handle; + unsigned long element; + }; unsigned long value; }; @@ -83,7 +86,7 @@ struct zram_stats { 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 */ - atomic64_t zero_pages; /* no. of zero filled pages */ + atomic64_t same_pages; /* no. of same element filled pages */ atomic64_t pages_stored; /* no. of pages currently stored */ atomic_long_t max_used_pages; /* no. of maximum pages stored */ atomic64_t writestall; /* no. of write slow paths */ -- 1.7.9.5