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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-25 19:29:09 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-25 19:29:09 +0100
commit7b46588f364f4f40c25f43ceabb6f705d20793e2 (patch)
tree29e80019ee791abe58176161f3ae2b766749b808 /drivers/block
parentmac80211_hwsim: Replace bogus hrtimer clockid (diff)
parentcheckpatch: remove false unbalanced braces warning (diff)
downloadlinux-7b46588f364f4f40c25f43ceabb6f705d20793e2.tar.xz
linux-7b46588f364f4f40c25f43ceabb6f705d20793e2.zip
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: - almost all of the rest of MM - misc bits - KASAN updates - procfs - lib/ updates - checkpatch updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (124 commits) checkpatch: remove false unbalanced braces warning checkpatch: notice unbalanced else braces in a patch checkpatch: add another old address for the FSF checkpatch: update $logFunctions checkpatch: warn on logging continuations checkpatch: warn on embedded function names lib/lz4: remove back-compat wrappers fs/pstore: fs/squashfs: change usage of LZ4 to work with new LZ4 version crypto: change LZ4 modules to work with new LZ4 module version lib/decompress_unlz4: change module to work with new LZ4 module version lib: update LZ4 compressor module lib/test_sort.c: make it explicitly non-modular lib: add CONFIG_TEST_SORT to enable self-test of sort() rbtree: use designated initializers linux/kernel.h: fix DIV_ROUND_CLOSEST to support negative divisors lib/find_bit.c: micro-optimise find_next_*_bit lib: add module support to atomic64 tests lib: add module support to glob tests lib: add module support to crc32 tests kernel/ksysfs.c: add __ro_after_init to bin_attribute structure ...
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/zram/zram_drv.c127
-rw-r--r--drivers/block/zram/zram_drv.h12
2 files changed, 69 insertions, 70 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c73fede582f7..e27d89a36c34 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -74,6 +74,17 @@ 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);
@@ -146,31 +157,46 @@ static inline void update_used_max(struct zram *zram,
} while (old_max != cur_max);
}
-static bool page_zero_filled(void *ptr)
+static inline void zram_fill_page(char *ptr, unsigned long len,
+ unsigned long value)
+{
+ int i;
+ unsigned long *page = (unsigned long *)ptr;
+
+ WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long)));
+
+ if (likely(value == 0)) {
+ memset(ptr, 0, len);
+ } else {
+ for (i = 0; i < len / sizeof(*page); i++)
+ page[i] = value;
+ }
+}
+
+static bool page_same_filled(void *ptr, unsigned long *element)
{
unsigned int pos;
unsigned long *page;
page = (unsigned long *)ptr;
- for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
- if (page[pos])
+ for (pos = 0; pos < PAGE_SIZE / sizeof(*page) - 1; pos++) {
+ if (page[pos] != page[pos + 1])
return false;
}
+ *element = page[pos];
+
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);
- else
- clear_page(user_mem);
+ zram_fill_page(user_mem + bvec->bv_offset, bvec->bv_len, element);
kunmap_atomic(user_mem);
flush_dcache_page(page);
@@ -363,7 +389,7 @@ 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);
@@ -391,18 +417,6 @@ static DEVICE_ATTR_RO(io_stat);
static DEVICE_ATTR_RO(mm_stat);
static DEVICE_ATTR_RO(debug_stat);
-static inline bool zram_meta_get(struct zram *zram)
-{
- if (atomic_inc_not_zero(&zram->refcount))
- return true;
- return false;
-}
-
-static inline void zram_meta_put(struct zram *zram)
-{
- atomic_dec(&zram->refcount);
-}
-
static void zram_meta_free(struct zram_meta *meta, u64 disksize)
{
size_t num_pages = disksize >> PAGE_SHIFT;
@@ -411,8 +425,11 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize)
/* Free all pages that are still in this zram device */
for (index = 0; index < num_pages; index++) {
unsigned long handle = meta->table[index].handle;
-
- if (!handle)
+ /*
+ * No memory is allocated for same element filled pages.
+ * Simply clear same page flag.
+ */
+ if (!handle || zram_test_flag(meta, index, ZRAM_SAME))
continue;
zs_free(meta->mem_pool, handle);
@@ -462,18 +479,20 @@ 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),
@@ -496,9 +515,9 @@ 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);
+ zram_fill_page(mem, PAGE_SIZE, meta->table[index].element);
return 0;
}
@@ -534,9 +553,9 @@ 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);
@@ -584,6 +603,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
struct zram_meta *meta = zram->meta;
struct zcomp_strm *zstrm = NULL;
unsigned long alloced_pages;
+ unsigned long element;
page = bvec->bv_page;
if (is_partial_io(bvec)) {
@@ -612,16 +632,17 @@ compress_again:
uncmem = user_mem;
}
- if (page_zero_filled(uncmem)) {
+ if (page_same_filled(uncmem, &element)) {
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;
}
@@ -859,22 +880,17 @@ static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio)
{
struct zram *zram = queue->queuedata;
- if (unlikely(!zram_meta_get(zram)))
- goto error;
-
blk_queue_split(queue, &bio, queue->bio_split);
if (!valid_io_request(zram, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size)) {
atomic64_inc(&zram->stats.invalid_io);
- goto put_zram;
+ goto error;
}
__zram_make_request(zram, bio);
- zram_meta_put(zram);
return BLK_QC_T_NONE;
-put_zram:
- zram_meta_put(zram);
+
error:
bio_io_error(bio);
return BLK_QC_T_NONE;
@@ -904,13 +920,11 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
struct bio_vec bv;
zram = bdev->bd_disk->private_data;
- if (unlikely(!zram_meta_get(zram)))
- goto out;
if (!valid_io_request(zram, sector, PAGE_SIZE)) {
atomic64_inc(&zram->stats.invalid_io);
err = -EINVAL;
- goto put_zram;
+ goto out;
}
index = sector >> SECTORS_PER_PAGE_SHIFT;
@@ -921,8 +935,6 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
bv.bv_offset = 0;
err = zram_bvec_rw(zram, &bv, index, offset, is_write);
-put_zram:
- zram_meta_put(zram);
out:
/*
* If I/O fails, just return error(ie, non-zero) without
@@ -955,17 +967,6 @@ static void zram_reset_device(struct zram *zram)
meta = zram->meta;
comp = zram->comp;
disksize = zram->disksize;
- /*
- * Refcount will go down to 0 eventually and r/w handler
- * cannot handle further I/O so it will bail out by
- * check zram_meta_get.
- */
- zram_meta_put(zram);
- /*
- * We want to free zram_meta in process context to avoid
- * deadlock between reclaim path and any other locks.
- */
- wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
/* Reset stats */
memset(&zram->stats, 0, sizeof(zram->stats));
@@ -1013,8 +1014,6 @@ static ssize_t disksize_store(struct device *dev,
goto out_destroy_comp;
}
- init_waitqueue_head(&zram->io_done);
- atomic_set(&zram->refcount, 1);
zram->meta = meta;
zram->comp = comp;
zram->disksize = disksize;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 74fcf10da374..caeff51f1571 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -61,7 +61,7 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
/* Flags for zram pages (table[page_no].value) */
enum zram_pageflags {
/* Page consists entirely of zeros */
- ZRAM_ZERO = ZRAM_FLAG_SHIFT,
+ 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 */
@@ -106,9 +109,6 @@ struct zram {
unsigned long limit_pages;
struct zram_stats stats;
- atomic_t refcount; /* refcount for zram_meta */
- /* wait all IO under all of cpu are done */
- wait_queue_head_t io_done;
/*
* This is the limit on amount of *uncompressed* worth of data
* we can store in a disk.