On Wed, Mar 9, 2022 at 7:50 PM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > On 3/9/22 08:40, Zhaoyang Huang wrote: > > From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx> > > > > 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. > > Hm I thought Mel removed the direct reclaim throttling based on bdi > congestion in his series [1]. Maybe block layers has other uses (I have no > idea), for tracking congestion, that should be mentioned instead? > > [1] > https://lore.kernel.org/all/20211022144651.19914-1-mgorman@xxxxxxxxxxxxxxxxxxx/ > As my understanding, the above patch change suspending on bdi congested for a given interval to be woken up by finish of request or bio. This patch is not against above one, which add one more scenario for setting bdi as congested. > > > > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx> > > --- > > block/blk-mq-tag.c | 18 +++++++++++++++++- > > include/linux/sbitmap.h | 1 + > > lib/sbitmap.c | 17 +++++++++++++++++ > > 3 files changed, 35 insertions(+), 1 deletion(-) > > > > diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c > > index 995336a..bd1e520 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" > > @@ -126,8 +127,11 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) > > if (tag != BLK_MQ_NO_TAG) > > goto found_tag; > > > > - if (data->flags & BLK_MQ_REQ_NOWAIT) > > + if (data->flags & BLK_MQ_REQ_NOWAIT) { > > + set_bdi_congested(data->q->disk->bdi,BLK_RW_SYNC); > > + set_bdi_congested(data->q->disk->bdi,BLK_RW_ASYNC); > > return BLK_MQ_NO_TAG; > > + } > > > > ws = bt_wait_ptr(bt, data->hctx); > > do { > > @@ -193,9 +197,21 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) > > return tag + tag_offset; > > } > > > > +static bool blk_mq_has_free_tags(struct blk_mq_tags *tags) > > +{ > > + if (!tags) > > + return true; > > + > > + return sbitmap_any_bit_clear(&tags->bitmap_tags.sb); > > +} > > + > > void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx, > > unsigned int tag) > > { > > + if (!blk_mq_has_free_tags(tags)) { > > + clear_bdi_congested(ctx->queue->disk->bdi, BLK_RW_SYNC); > > + clear_bdi_congested(ctx->queue->disk->bdi, BLK_RW_ASYNC); > > + } > > if (!blk_mq_tag_is_reserved(tags, tag)) { > > const int real_tag = tag - tags->nr_reserved_tags; > > > > diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h > > index 4a6ff27..30a5553 100644 > > --- a/include/linux/sbitmap.h > > +++ b/include/linux/sbitmap.h > > @@ -210,6 +210,7 @@ static inline void sbitmap_free(struct sbitmap *sb) > > * Return: true if any bit in the bitmap is set, false otherwise. > > */ > > bool sbitmap_any_bit_set(const struct sbitmap *sb); > > +bool sbitmap_any_bit_clear(const struct sbitmap *sb); > > > > #define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift) > > #define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U)) > > diff --git a/lib/sbitmap.c b/lib/sbitmap.c > > index 2709ab8..baa30d8 100644 > > --- a/lib/sbitmap.c > > +++ b/lib/sbitmap.c > > @@ -309,6 +309,23 @@ bool sbitmap_any_bit_set(const struct sbitmap *sb) > > } > > EXPORT_SYMBOL_GPL(sbitmap_any_bit_set); > > > > +bool sbitmap_any_bit_clear(const struct sbitmap *sb) > > +{ > > + unsigned int i; > > + > > + for (i = 0; i < sb->map_nr; i++) { > > + const struct sbitmap_word *word = &sb->map[i]; > > + unsigned long mask = word->word & ~word->cleared; > > + unsigned long ret; > > + > > + ret = find_first_zero_bit(&mask, word->depth); > > + if (ret < word->depth) > > + return true; > > + } > > + return false; > > +} > > +EXPORT_SYMBOL_GPL(sbitmap_any_bit_clear); > > + > > static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set) > > { > > unsigned int i, weight = 0; >
