subject:"\[PATCH 2\/5\] blk\-mq\: introduce BLK_MQ_F_GLOBAL

Re: [PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

2018-02-05 Thread Ming Lei

On Mon, Feb 05, 2018 at 07:54:29AM +0100, Hannes Reinecke wrote:
> On 02/03/2018 05:21 AM, Ming Lei wrote:
> > Quite a few HBAs(such as HPSA, megaraid, mpt3sas, ..) support multiple
> > reply queues, but tags is often HBA wide.
> > 
> > These HBAs have switched to use pci_alloc_irq_vectors(PCI_IRQ_AFFINITY)
> > for automatic affinity assignment.
> > 
> > Now 84676c1f21e8ff5(genirq/affinity: assign vectors to all possible CPUs)
> > has been merged to V4.16-rc, and it is easy to allocate all offline CPUs
> > for some irq vectors, this can't be avoided even though the allocation
> > is improved.
> > 
> > So all these drivers have to avoid to ask HBA to complete request in
> > reply queue which hasn't online CPUs assigned, and HPSA has been broken
> > with v4.15+:
> > 
> > https://marc.info/?l=linux-kernel=151748144730409=2
> > 
> > This issue can be solved generically and easily via blk_mq(scsi_mq) multiple
> > hw queue by mapping each reply queue into hctx, but one tricky thing is
> > the HBA wide(instead of hw queue wide) tags.
> > 
> > This patch is based on the following Hannes's patch:
> > 
> > https://marc.info/?l=linux-block=149132580511346=2
> > 
> > One big difference with Hannes's is that this patch only makes the tags 
> > sbitmap
> > and active_queues data structure HBA wide, and others are kept as NUMA 
> > locality,
> > such as request, hctx, tags, ...
> > 
> > The following patch will support global tags on null_blk, also the 
> > performance
> > data is provided, no obvious performance loss is observed when the whole
> > hw queue depth is same.
> > 
> > Cc: Hannes Reinecke 
> > Cc: Arun Easi 
> > Cc: Omar Sandoval ,
> > Cc: "Martin K. Petersen" ,
> > Cc: James Bottomley ,
> > Cc: Christoph Hellwig ,
> > Cc: Don Brace 
> > Cc: Kashyap Desai 
> > Cc: Peter Rivera 
> > Cc: Laurence Oberman 
> > Cc: Mike Snitzer 
> > Signed-off-by: Ming Lei 
> > ---
> >  block/blk-mq-debugfs.c |  1 +
> >  block/blk-mq-sched.c   |  2 +-
> >  block/blk-mq-tag.c | 23 ++-
> >  block/blk-mq-tag.h |  5 -
> >  block/blk-mq.c | 29 -
> >  block/blk-mq.h |  3 ++-
> >  include/linux/blk-mq.h |  2 ++
> >  7 files changed, 52 insertions(+), 13 deletions(-)
> > 
> > diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> > index 0dfafa4b655a..0f0fafe03f5d 100644
> > --- a/block/blk-mq-debugfs.c
> > +++ b/block/blk-mq-debugfs.c
> > @@ -206,6 +206,7 @@ static const char *const hctx_flag_name[] = {
> > HCTX_FLAG_NAME(SHOULD_MERGE),
> > HCTX_FLAG_NAME(TAG_SHARED),
> > HCTX_FLAG_NAME(SG_MERGE),
> > +   HCTX_FLAG_NAME(GLOBAL_TAGS),
> > HCTX_FLAG_NAME(BLOCKING),
> > HCTX_FLAG_NAME(NO_SCHED),
> >  };
> > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> > index 55c0a745b427..191d4bc95f0e 100644
> > --- a/block/blk-mq-sched.c
> > +++ b/block/blk-mq-sched.c
> > @@ -495,7 +495,7 @@ static int blk_mq_sched_alloc_tags(struct request_queue 
> > *q,
> > int ret;
> >  
> > hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
> > -  set->reserved_tags);
> > +  set->reserved_tags, false);
> > if (!hctx->sched_tags)
> > return -ENOMEM;
> >  
> > diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
> > index 571797dc36cb..66377d09eaeb 100644
> > --- a/block/blk-mq-tag.c
> > +++ b/block/blk-mq-tag.c
> > @@ -379,9 +379,11 @@ static struct blk_mq_tags 
> > *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
> > return NULL;
> >  }
> >  
> > -struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
> > +struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set,
> > +unsigned int total_tags,
> >  unsigned int reserved_tags,
> > -int node, int alloc_policy)
> > +int node, int alloc_policy,
> > +bool global_tag)
> >  {
> > struct blk_mq_tags *tags;
> >  
> > @@ -397,6 +399,14 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int 
> > total_tags,
> > tags->nr_tags = total_tags;
> > tags->nr_reserved_tags = reserved_tags;
> >  
> > +   WARN_ON(global_tag && !set->global_tags);
> > +   if (global_tag && set->global_tags) {
> > +   tags->bitmap_tags = set->global_tags->bitmap_tags;
> > +   tags->breserved_tags = set->global_tags->breserved_tags;
> > +   tags->active_queues = set->global_tags->active_queues;
> > +   tags->global_tags = true;
> > +   return tags;
> > +   }
> > tags->bitmap_tags = >__bitmap_tags;
> >

Re: [PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

2018-02-04 Thread Hannes Reinecke

On 02/03/2018 05:21 AM, Ming Lei wrote:
> Quite a few HBAs(such as HPSA, megaraid, mpt3sas, ..) support multiple
> reply queues, but tags is often HBA wide.
> 
> These HBAs have switched to use pci_alloc_irq_vectors(PCI_IRQ_AFFINITY)
> for automatic affinity assignment.
> 
> Now 84676c1f21e8ff5(genirq/affinity: assign vectors to all possible CPUs)
> has been merged to V4.16-rc, and it is easy to allocate all offline CPUs
> for some irq vectors, this can't be avoided even though the allocation
> is improved.
> 
> So all these drivers have to avoid to ask HBA to complete request in
> reply queue which hasn't online CPUs assigned, and HPSA has been broken
> with v4.15+:
> 
>   https://marc.info/?l=linux-kernel=151748144730409=2
> 
> This issue can be solved generically and easily via blk_mq(scsi_mq) multiple
> hw queue by mapping each reply queue into hctx, but one tricky thing is
> the HBA wide(instead of hw queue wide) tags.
> 
> This patch is based on the following Hannes's patch:
> 
>   https://marc.info/?l=linux-block=149132580511346=2
> 
> One big difference with Hannes's is that this patch only makes the tags 
> sbitmap
> and active_queues data structure HBA wide, and others are kept as NUMA 
> locality,
> such as request, hctx, tags, ...
> 
> The following patch will support global tags on null_blk, also the performance
> data is provided, no obvious performance loss is observed when the whole
> hw queue depth is same.
> 
> Cc: Hannes Reinecke 
> Cc: Arun Easi 
> Cc: Omar Sandoval ,
> Cc: "Martin K. Petersen" ,
> Cc: James Bottomley ,
> Cc: Christoph Hellwig ,
> Cc: Don Brace 
> Cc: Kashyap Desai 
> Cc: Peter Rivera 
> Cc: Laurence Oberman 
> Cc: Mike Snitzer 
> Signed-off-by: Ming Lei 
> ---
>  block/blk-mq-debugfs.c |  1 +
>  block/blk-mq-sched.c   |  2 +-
>  block/blk-mq-tag.c | 23 ++-
>  block/blk-mq-tag.h |  5 -
>  block/blk-mq.c | 29 -
>  block/blk-mq.h |  3 ++-
>  include/linux/blk-mq.h |  2 ++
>  7 files changed, 52 insertions(+), 13 deletions(-)
> 
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 0dfafa4b655a..0f0fafe03f5d 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -206,6 +206,7 @@ static const char *const hctx_flag_name[] = {
>   HCTX_FLAG_NAME(SHOULD_MERGE),
>   HCTX_FLAG_NAME(TAG_SHARED),
>   HCTX_FLAG_NAME(SG_MERGE),
> + HCTX_FLAG_NAME(GLOBAL_TAGS),
>   HCTX_FLAG_NAME(BLOCKING),
>   HCTX_FLAG_NAME(NO_SCHED),
>  };
> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> index 55c0a745b427..191d4bc95f0e 100644
> --- a/block/blk-mq-sched.c
> +++ b/block/blk-mq-sched.c
> @@ -495,7 +495,7 @@ static int blk_mq_sched_alloc_tags(struct request_queue 
> *q,
>   int ret;
>  
>   hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
> -set->reserved_tags);
> +set->reserved_tags, false);
>   if (!hctx->sched_tags)
>   return -ENOMEM;
>  
> diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
> index 571797dc36cb..66377d09eaeb 100644
> --- a/block/blk-mq-tag.c
> +++ b/block/blk-mq-tag.c
> @@ -379,9 +379,11 @@ static struct blk_mq_tags 
> *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
>   return NULL;
>  }
>  
> -struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
> +struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set,
> +  unsigned int total_tags,
>unsigned int reserved_tags,
> -  int node, int alloc_policy)
> +  int node, int alloc_policy,
> +  bool global_tag)
>  {
>   struct blk_mq_tags *tags;
>  
> @@ -397,6 +399,14 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int 
> total_tags,
>   tags->nr_tags = total_tags;
>   tags->nr_reserved_tags = reserved_tags;
>  
> + WARN_ON(global_tag && !set->global_tags);
> + if (global_tag && set->global_tags) {
> + tags->bitmap_tags = set->global_tags->bitmap_tags;
> + tags->breserved_tags = set->global_tags->breserved_tags;
> + tags->active_queues = set->global_tags->active_queues;
> + tags->global_tags = true;
> + return tags;
> + }
>   tags->bitmap_tags = >__bitmap_tags;
>   tags->breserved_tags = >__breserved_tags;
>   tags->active_queues = >__active_queues;
Do we really need the 'global_tag' flag here?
Can't we just rely on the ->global_tags pointer to be set?

> @@ -406,8 +416,10 @@ struct blk_mq_tags

[PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

2018-02-02 Thread Ming Lei

Quite a few HBAs(such as HPSA, megaraid, mpt3sas, ..) support multiple
reply queues, but tags is often HBA wide.

These HBAs have switched to use pci_alloc_irq_vectors(PCI_IRQ_AFFINITY)
for automatic affinity assignment.

Now 84676c1f21e8ff5(genirq/affinity: assign vectors to all possible CPUs)
has been merged to V4.16-rc, and it is easy to allocate all offline CPUs
for some irq vectors, this can't be avoided even though the allocation
is improved.

So all these drivers have to avoid to ask HBA to complete request in
reply queue which hasn't online CPUs assigned, and HPSA has been broken
with v4.15+:

https://marc.info/?l=linux-kernel=151748144730409=2

This issue can be solved generically and easily via blk_mq(scsi_mq) multiple
hw queue by mapping each reply queue into hctx, but one tricky thing is
the HBA wide(instead of hw queue wide) tags.

This patch is based on the following Hannes's patch:

https://marc.info/?l=linux-block=149132580511346=2

One big difference with Hannes's is that this patch only makes the tags sbitmap
and active_queues data structure HBA wide, and others are kept as NUMA locality,
such as request, hctx, tags, ...

The following patch will support global tags on null_blk, also the performance
data is provided, no obvious performance loss is observed when the whole
hw queue depth is same.

Cc: Hannes Reinecke 
Cc: Arun Easi 
Cc: Omar Sandoval ,
Cc: "Martin K. Petersen" ,
Cc: James Bottomley ,
Cc: Christoph Hellwig ,
Cc: Don Brace 
Cc: Kashyap Desai 
Cc: Peter Rivera 
Cc: Laurence Oberman 
Cc: Mike Snitzer 
Signed-off-by: Ming Lei 
---
 block/blk-mq-debugfs.c |  1 +
 block/blk-mq-sched.c   |  2 +-
 block/blk-mq-tag.c | 23 ++-
 block/blk-mq-tag.h |  5 -
 block/blk-mq.c | 29 -
 block/blk-mq.h |  3 ++-
 include/linux/blk-mq.h |  2 ++
 7 files changed, 52 insertions(+), 13 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 0dfafa4b655a..0f0fafe03f5d 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -206,6 +206,7 @@ static const char *const hctx_flag_name[] = {
HCTX_FLAG_NAME(SHOULD_MERGE),
HCTX_FLAG_NAME(TAG_SHARED),
HCTX_FLAG_NAME(SG_MERGE),
+   HCTX_FLAG_NAME(GLOBAL_TAGS),
HCTX_FLAG_NAME(BLOCKING),
HCTX_FLAG_NAME(NO_SCHED),
 };
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 55c0a745b427..191d4bc95f0e 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -495,7 +495,7 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q,
int ret;
 
hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
-  set->reserved_tags);
+  set->reserved_tags, false);
if (!hctx->sched_tags)
return -ENOMEM;
 
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 571797dc36cb..66377d09eaeb 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -379,9 +379,11 @@ static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct 
blk_mq_tags *tags,
return NULL;
 }
 
-struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
+struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set,
+unsigned int total_tags,
 unsigned int reserved_tags,
-int node, int alloc_policy)
+int node, int alloc_policy,
+bool global_tag)
 {
struct blk_mq_tags *tags;
 
@@ -397,6 +399,14 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int 
total_tags,
tags->nr_tags = total_tags;
tags->nr_reserved_tags = reserved_tags;
 
+   WARN_ON(global_tag && !set->global_tags);
+   if (global_tag && set->global_tags) {
+   tags->bitmap_tags = set->global_tags->bitmap_tags;
+   tags->breserved_tags = set->global_tags->breserved_tags;
+   tags->active_queues = set->global_tags->active_queues;
+   tags->global_tags = true;
+   return tags;
+   }
tags->bitmap_tags = >__bitmap_tags;
tags->breserved_tags = >__breserved_tags;
tags->active_queues = >__active_queues;
@@ -406,8 +416,10 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int 
total_tags,
 
 void blk_mq_free_tags(struct blk_mq_tags *tags)
 {
-   sbitmap_queue_free(tags->bitmap_tags);
-   sbitmap_queue_free(tags->breserved_tags);
+   if (!tags->global_tags) {
+   sbitmap_queue_free(tags->bitmap_tags);
+

Re: [PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

Re: [PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

[PATCH 2/5] blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS

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