From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Subject: zram: rename zstrm find-release functions
This has started as a 'add zlib support' work, but after some thinking I
saw no blockers for a bigger change -- a switch to crypto API.
We don't have an idle zstreams list anymore and our write path now works
absolutely differently, preventing preemption during compression. This
removes possibilities of read paths preempting writes at wrong places and
opens the door for a move from custom LZO/LZ4 compression backends
implementation to a more generic one, using crypto compress API.
This patch set also eliminates the need of a new context-less crypto API
interface, which was quite hard to sell, so we can move along faster.
benchmarks:
(x86_64, 4GB, zram-perf script)
perf reported run-time fio (max jobs=3). I performed fio test with the
increasing number of parallel jobs (max to 3) on a 3G zram device, using
`static' data and the following crypto comp algorithms:
842, deflate, lz4, lz4hc, lzo
the output was:
- test running time (which can tell us what algorithms performs faster)
and
- zram mm_stat (which tells the compressed memory size, max used memory, etc).
It's just for information. for example, LZ4HC has twice the running time
of LZO, but the compressed memory size is: 23592960 vs 34603008 bytes.
test-fio-zram-842
197.907655282 seconds time elapsed
201.623142884 seconds time elapsed
226.854291345 seconds time elapsed
test-fio-zram-DEFLATE
253.259516155 seconds time elapsed
258.148563401 seconds time elapsed
290.251909365 seconds time elapsed
test-fio-zram-LZ4
27.022598717 seconds time elapsed
29.580522717 seconds time elapsed
33.293463430 seconds time elapsed
test-fio-zram-LZ4HC
56.393954615 seconds time elapsed
74.904659747 seconds time elapsed
101.940998564 seconds time elapsed
test-fio-zram-LZO
28.155948075 seconds time elapsed
30.390036330 seconds time elapsed
34.455773159 seconds time elapsed
zram mm_stat-s (max fio jobs=3)
test-fio-zram-842
mm_stat (jobs1): 3221225472 673185792 690266112 0 690266112 0 0
mm_stat (jobs2): 3221225472 673185792 690266112 0 690266112 0 0
mm_stat (jobs3): 3221225472 673185792 690266112 0 690266112 0 0
test-fio-zram-DEFLATE
mm_stat (jobs1): 3221225472 24379392 37761024 0 37761024 0 0
mm_stat (jobs2): 3221225472 24379392 37761024 0 37761024 0 0
mm_stat (jobs3): 3221225472 24379392 37761024 0 37761024 0 0
test-fio-zram-LZ4
mm_stat (jobs1): 3221225472 23592960 37761024 0 37761024 0 0
mm_stat (jobs2): 3221225472 23592960 37761024 0 37761024 0 0
mm_stat (jobs3): 3221225472 23592960 37761024 0 37761024 0 0
test-fio-zram-LZ4HC
mm_stat (jobs1): 3221225472 23592960 37761024 0 37761024 0 0
mm_stat (jobs2): 3221225472 23592960 37761024 0 37761024 0 0
mm_stat (jobs3): 3221225472 23592960 37761024 0 37761024 0 0
test-fio-zram-LZO
mm_stat (jobs1): 3221225472 34603008 50335744 0 50335744 0 0
mm_stat (jobs2): 3221225472 34603008 50335744 0 50335744 0 0
mm_stat (jobs3): 3221225472 34603008 50335744 0 50339840 0 0
This patch (of 8):
We don't perform any zstream idle list lookup anymore, so
zcomp_strm_find()/zcomp_strm_release() names are not representative.
Rename to zcomp_stream_get()/zcomp_stream_put().
Link: http://lkml.kernel.org/r/20160531122017.2878-2-sergey.senozhatsky@xxxxxxxxx
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zcomp.c | 4 ++--
drivers/block/zram/zcomp.h | 4 ++--
drivers/block/zram/zram_drv.c | 8 ++++----
3 files changed, 8 insertions(+), 8 deletions(-)
diff -puN drivers/block/zram/zcomp.c~zram-rename-zstrm-find-release-functions drivers/block/zram/zcomp.c
--- a/drivers/block/zram/zcomp.c~zram-rename-zstrm-find-release-functions
+++ a/drivers/block/zram/zcomp.c
@@ -95,12 +95,12 @@ bool zcomp_available_algorithm(const cha
return find_backend(comp) != NULL;
}
-struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
{
return *get_cpu_ptr(comp->stream);
}
-void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+void zcomp_stream_put(struct zcomp *comp)
{
put_cpu_ptr(comp->stream);
}
diff -puN drivers/block/zram/zcomp.h~zram-rename-zstrm-find-release-functions drivers/block/zram/zcomp.h
--- a/drivers/block/zram/zcomp.h~zram-rename-zstrm-find-release-functions
+++ a/drivers/block/zram/zcomp.h
@@ -48,8 +48,8 @@ bool zcomp_available_algorithm(const cha
struct zcomp *zcomp_create(const char *comp);
void zcomp_destroy(struct zcomp *comp);
-struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
-void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
+struct zcomp_strm *zcomp_stream_get(struct zcomp *comp);
+void zcomp_stream_put(struct zcomp *comp);
int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
const unsigned char *src, size_t *dst_len);
diff -puN drivers/block/zram/zram_drv.c~zram-rename-zstrm-find-release-functions drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-rename-zstrm-find-release-functions
+++ a/drivers/block/zram/zram_drv.c
@@ -695,7 +695,7 @@ compress_again:
goto out;
}
- zstrm = zcomp_strm_find(zram->comp);
+ zstrm = zcomp_stream_get(zram->comp);
ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
if (!is_partial_io(bvec)) {
kunmap_atomic(user_mem);
@@ -734,7 +734,7 @@ compress_again:
__GFP_NOWARN |
__GFP_HIGHMEM);
if (!handle) {
- zcomp_strm_release(zram->comp, zstrm);
+ zcomp_stream_put(zram->comp);
zstrm = NULL;
atomic64_inc(&zram->stats.writestall);
@@ -769,7 +769,7 @@ compress_again:
memcpy(cmem, src, clen);
}
- zcomp_strm_release(zram->comp, zstrm);
+ zcomp_stream_put(zram->comp);
zstrm = NULL;
zs_unmap_object(meta->mem_pool, handle);
@@ -789,7 +789,7 @@ compress_again:
atomic64_inc(&zram->stats.pages_stored);
out:
if (zstrm)
- zcomp_strm_release(zram->comp, zstrm);
+ zcomp_stream_put(zram->comp);
if (is_partial_io(bvec))
kfree(uncmem);
return ret;
_
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