Allow user to set the QUEUE_FLAG_NOWAIT optionally using module
parameter to retain the default behaviour. Also, update respective
allocation flags in the write path. Following are the performance
numbers with io_uring fio engine for random read, note that device has
been populated fully with randwrite workload before taking these
numbers :-
* linux-block (for-next) # grep IOPS zram*fio | column -t
default-nowait-off-1.fio: read: IOPS=802k, BW=3133MiB/s
default-nowait-off-2.fio: read: IOPS=796k, BW=3111MiB/s
default-nowait-off-3.fio: read: IOPS=796k, BW=3108MiB/s
nowait-on-1.fio: read: IOPS=857k, BW=3346MiB/s
nowait-on-2.fio: read: IOPS=857k, BW=3347MiB/s
nowait-on-3.fio: read: IOPS=858k, BW=3353MiB/s
* linux-block (for-next) # grep cpu zram*fio | column -t
default-nowait-off-1.fio: cpu : usr=5.82%, sys=13.54%, ctx=36301915
default-nowait-off-2.fio: cpu : usr=5.84%, sys=13.03%, ctx=37781937
default-nowait-off-3.fio: cpu : usr=5.84%, sys=12.90%, ctx=37492533
nowait-on-1.fio: cpu : usr=1.74%, sys=97.62%, ctx=24068,
nowait-on-2.fio: cpu : usr=1.74%, sys=97.57%, ctx=24674,
nowait-on-3.fio: cpu : usr=1.76%, sys=97.59%, ctx=24725,
Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index f6d90f1ba5cf..b2e419f15f71 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -36,6 +36,10 @@
#include "zram_drv.h"
+static bool g_nowait;
+module_param_named(nowait, g_nowait, bool, 0444);
+MODULE_PARM_DESC(nowait, "set QUEUE_FLAG_NOWAIT. Default: False");
+
static DEFINE_IDR(zram_index_idr);
/* idr index must be protected */
static DEFINE_MUTEX(zram_index_mutex);
@@ -1540,9 +1544,10 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index)
static int zram_bvec_write_partial(struct zram *zram, struct bio_vec *bvec,
u32 index, int offset, struct bio *bio)
{
- struct page *page = alloc_page(GFP_NOIO);
+ struct page *page;
int ret;
+ page = alloc_page(bio->bi_opf & REQ_NOWAIT ? GFP_NOWAIT : GFP_NOIO);
if (!page)
return -ENOMEM;
@@ -2215,6 +2220,8 @@ static int zram_add(void)
/* zram devices sort of resembles non-rotational disks */
blk_queue_flag_set(QUEUE_FLAG_NONROT, zram->disk->queue);
blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, zram->disk->queue);
+ if (g_nowait)
+ blk_queue_flag_set(QUEUE_FLAG_NOWAIT, zram->disk->queue);
/*
* To ensure that we always get PAGE_SIZE aligned
--
2.40.0
