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authorSergey Senozhatsky <sergey.senozhatsky.work@gmail.com>2018-04-06 02:24:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-06 07:36:26 +0300
commit60f5921a9a4f126e081318bd6bb2bc2798b7bba8 (patch)
tree46121f0c217ab40a3da0b439ca0899a9372fce73 /drivers/block/zram
parent010b495e2fa32353d0ef6aa70a8169e5ef617a15 (diff)
downloadlinux-60f5921a9a4f126e081318bd6bb2bc2798b7bba8.tar.xz
zram: drop max_zpage_size and use zs_huge_class_size()
Remove ZRAM's enforced "huge object" value and use zsmalloc huge-class watermark instead, which makes more sense. TEST - I used a 1G zram device, LZO compression back-end, original data set size was 444MB. Looking at zsmalloc classes stats the test ended up to be pretty fair. BASE ZRAM/ZSMALLOC ===================== zram mm_stat 498978816 191482495 199831552 0 199831552 15634 0 zsmalloc classes class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage freeable ... 151 2448 0 0 1240 1240 744 3 0 168 2720 0 0 4200 4200 2800 2 0 190 3072 0 0 10100 10100 7575 3 0 202 3264 0 0 380 380 304 4 0 254 4096 0 0 10620 10620 10620 1 0 Total 7 46 106982 106187 48787 0 PATCHED ZRAM/ZSMALLOC ===================== zram mm_stat 498978816 182579184 194248704 0 194248704 15628 0 zsmalloc classes class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage freeable ... 151 2448 0 0 1240 1240 744 3 0 168 2720 0 0 4200 4200 2800 2 0 190 3072 0 0 10100 10100 7575 3 0 202 3264 0 0 7180 7180 5744 4 0 254 4096 0 0 3820 3820 3820 1 0 Total 8 45 106959 106193 47424 0 As we can see, we reduced the number of objects stored in class-4096, because a huge number of objects which we previously forcibly stored in class-4096 now stored in non-huge class-3264. This results in lower memory consumption: - zsmalloc now uses 47424 physical pages, which is less than 48787 pages zsmalloc used before. - objects that we store in class-3264 share zspages. That's why overall the number of pages that both class-4096 and class-3264 consumed went down from 10924 to 9564. [sergey.senozhatsky.work@gmail.com: add pool param to zs_huge_class_size()] Link: http://lkml.kernel.org/r/20180314081833.1096-3-sergey.senozhatsky@gmail.com Link: http://lkml.kernel.org/r/20180306070639.7389-3-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/zram')
-rw-r--r--drivers/block/zram/zram_drv.c9
-rw-r--r--drivers/block/zram/zram_drv.h16
2 files changed, 8 insertions, 17 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 0afa6c8c3857..bd38f46801d3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -44,6 +44,11 @@ static const char *default_compressor = "lzo";
/* Module params (documentation at end) */
static unsigned int num_devices = 1;
+/*
+ * Pages that compress to sizes equals or greater than this are stored
+ * uncompressed in memory.
+ */
+static size_t huge_class_size;
static void zram_free_page(struct zram *zram, size_t index);
@@ -786,6 +791,8 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
return false;
}
+ if (!huge_class_size)
+ huge_class_size = zs_huge_class_size(zram->mem_pool);
return true;
}
@@ -965,7 +972,7 @@ compress_again:
return ret;
}
- if (unlikely(comp_len > max_zpage_size)) {
+ if (unlikely(comp_len >= huge_class_size)) {
if (zram_wb_enabled(zram) && allow_wb) {
zcomp_stream_put(zram->comp);
ret = write_to_bdev(zram, bvec, index, bio, &element);
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 31762db861e3..d71c8000a964 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -21,22 +21,6 @@
#include "zcomp.h"
-/*-- Configurable parameters */
-
-/*
- * Pages that compress to size greater than this are stored
- * uncompressed in memory.
- */
-static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
-
-/*
- * NOTE: max_zpage_size must be less than or equal to:
- * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
- * always return failure.
- */
-
-/*-- End of configurable params */
-
#define SECTOR_SHIFT 9
#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)