[RFC PATCHv2] block: set bdi congested when no tag available

zhaoyang.huang
2022-06-16T12:32:54Z

From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

In previous version, block layer will set bdi to be congested when
get_request fail, which may throttle direct_reclaim. Move them back
under current blk-mq design.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
v2: simplify the code
---
---
block/blk-mq-tag.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 995336a..0cbc445 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -11,6 +11,7 @@

#include <linux/blk-mq.h>
#include <linux/delay.h>
+#include <linux/backing-dev.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-sched.h"
@@ -126,6 +127,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
if (tag != BLK_MQ_NO_TAG)
goto found_tag;

+ set_bdi_congested(data->q->disk->bdi,BLK_RW_SYNC);
+ set_bdi_congested(data->q->disk->bdi,BLK_RW_ASYNC);
if (data->flags & BLK_MQ_REQ_NOWAIT)
return BLK_MQ_NO_TAG;

@@ -190,6 +193,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
return BLK_MQ_NO_TAG;
}
+ clear_bdi_congested(data->q->disk->bdi,BLK_RW_SYNC);
+ clear_bdi_congested(data->q->disk->bdi,BLK_RW_ASYNC);
return tag + tag_offset;
}

--
1.9.1