search for: percpu_ida

From: Matthew Wilcox <mawilcox at microsoft.com> This is a pretty rough-and-ready conversion of the target drivers from using percpu_ida to sbitmap. It compiles; I don't have a target setup, so it's completely untested. I haven't tried to do anything particularly clever here, so it's possible that, for example, the wait queue in iscsi_target_util could be more clever, like the block layer uses multiple wait queues...

Removing the percpu_ida code nets over 400 lines of removal. It's not as spectacular as deleting an entire architecture, but it's still a worthy reduction in lines of code. Untested due to lack of hardware and not understanding how to set up a target platform. Changes from v1: - Fixed bugs pointed out by Jens...

Removing the percpu_ida code nets over 400 lines of removal. It's not as spectacular as deleting an entire architecture, but it's still a worthy reduction in lines of code. Untested due to lack of hardware and not understanding how to set up a target platform. Changes from v1: - Fixed bugs pointed out by Jens...

On 5/15/18 10:00 AM, Matthew Wilcox wrote: > From: Matthew Wilcox <mawilcox at microsoft.com> > > The sbitmap and the percpu_ida perform essentially the same task, > allocating tags for commands. Since the sbitmap is more used than > the percpu_ida, convert the percpu_ida users to the sbitmap API. It should also be the same performance as percpu_ida in light use, and performs much better at > 50% utilization of th...

On 5/15/18 10:00 AM, Matthew Wilcox wrote: > From: Matthew Wilcox <mawilcox at microsoft.com> > > The sbitmap and the percpu_ida perform essentially the same task, > allocating tags for commands. Since the sbitmap is more used than > the percpu_ida, convert the percpu_ida users to the sbitmap API. It should also be the same performance as percpu_ida in light use, and performs much better at > 50% utilization of th...

...nux/idr.h | 2 +- lib/idr.c | 38 +++++++++++++++++++++----------------- 2 files changed, 22 insertions(+), 18 deletions(-) diff --git a/include/linux/idr.h b/include/linux/idr.h index f0db12b..cdf39be 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -267,7 +267,7 @@ struct percpu_ida { * will just keep looking - but the bitmap _must_ be set whenever a * percpu freelist does have tags. */ - unsigned long *cpus_have_tags; + cpumask_t cpus_have_tags; struct { spinlock_t lock; diff --git a/lib/idr.c b/lib/idr.c index 26495e1..15c021c 100644 --- a/lib/idr.c +++...

...lt;linux/spinlock_types.h> +#include <linux/wait.h> /* * We want shallower trees and thus more bits covered at each layer. 8 @@ -243,4 +245,55 @@ static inline int ida_get_new(struct ida *ida, int *p_id) void __init idr_init_cache(void); +/* Percpu IDA/tag allocator */ + +struct percpu_ida_cpu; + +struct percpu_ida { + /* + * number of tags available to be allocated, as passed to + * percpu_ida_init() + */ + unsigned nr_tags; + + struct percpu_ida_cpu __percpu *tag_cpu; + + /* + * Bitmap of cpus that (may) have tags on their percpu freelists: + * steal_tags() uses this to deci...

...o relationship with the existing code. Apart from duplicating its functionality :( > > ... > > @@ -243,4 +245,55 @@ static inline int ida_get_new(struct ida *ida, int *p_id) > > void __init idr_init_cache(void); > > +/* Percpu IDA/tag allocator */ > + > +struct percpu_ida_cpu; > + > +struct percpu_ida { > + /* > + * number of tags available to be allocated, as passed to > + * percpu_ida_init() > + */ > + unsigned nr_tags; > + > + struct percpu_ida_cpu __percpu *tag_cpu; > + > + /* > + * Bitmap of cpus that (may) have tags on...

...o relationship with the existing code. Apart from duplicating its functionality :( > > ... > > @@ -243,4 +245,55 @@ static inline int ida_get_new(struct ida *ida, int *p_id) > > void __init idr_init_cache(void); > > +/* Percpu IDA/tag allocator */ > + > +struct percpu_ida_cpu; > + > +struct percpu_ida { > + /* > + * number of tags available to be allocated, as passed to > + * percpu_ida_init() > + */ > + unsigned nr_tags; > + > + struct percpu_ida_cpu __percpu *tag_cpu; > + > + /* > + * Bitmap of cpus that (may) have tags on...

Matthew, > Removing the percpu_ida code nets over 400 lines of removal. It's not > as spectacular as deleting an entire architecture, but it's still a > worthy reduction in lines of code. Since most of the changes are in scsi or target, should I take this series through my tree? -- Martin K. Petersen Oracle Linux E...

On Thu, Jun 14, 2018 at 10:06:58PM -0400, Martin K. Petersen wrote: > > Matthew, > > > Removing the percpu_ida code nets over 400 lines of removal. It's not > > as spectacular as deleting an entire architecture, but it's still a > > worthy reduction in lines of code. > > Since most of the changes are in scsi or target, should I take this > series through my tree? I'd welc...

On 5/15/18 10:11 AM, Jens Axboe wrote: > On 5/15/18 10:00 AM, Matthew Wilcox wrote: >> From: Matthew Wilcox <mawilcox at microsoft.com> >> >> The sbitmap and the percpu_ida perform essentially the same task, >> allocating tags for commands. Since the sbitmap is more used than >> the percpu_ida, convert the percpu_ida users to the sbitmap API. > > It should also be the same performance as percpu_ida in light use, and > performs much better at &gt...

...39;m constitutionally reluctant to ever assume that any out-of-tree code will be merged. Maybe you'll get hit by a bus, and maybe the code sucks ;) Are you sure that the two things are so tangled together that they must live in the same file? If there's some nice layering between ida and percpu_ida then perhaps such a physical separation would remain appropriate? > (and if so, any preference on the naming?) percpu_ida.c?

...39;m constitutionally reluctant to ever assume that any out-of-tree code will be merged. Maybe you'll get hit by a bus, and maybe the code sucks ;) Are you sure that the two things are so tangled together that they must live in the same file? If there's some nice layering between ida and percpu_ida then perhaps such a physical separation would remain appropriate? > (and if so, any preference on the naming?) percpu_ida.c?

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi folks, This is an updated series for adding tag pre-allocation support of target fabric descriptor memory, utilizing Kent's latest per-cpu ida bits here, along with Christoph Lameter's latest comments: [PATCH 04/10] idr: Percpu ida http://marc.info/?l=linux-kernel&m=137160026006974&w=2 The first patch is a

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi folks, This is an updated series for adding tag pre-allocation support of target fabric descriptor memory, utilizing Kent's latest per-cpu ida bits here, along with Christoph Lameter's latest comments: [PATCH 04/10] idr: Percpu ida http://marc.info/?l=linux-kernel&m=137160026006974&w=2 The first patch is a

From: Matthew Wilcox <mawilcox at microsoft.com> The sbitmap and the percpu_ida perform essentially the same task, allocating tags for commands. Since the sbitmap is more used than the percpu_ida, convert the percpu_ida users to the sbitmap API. Signed-off-by: Matthew Wilcox <mawilcox at microsoft.com> --- drivers/scsi/qla2xxx/qla_target.c | 16 ++++++----- dri...

...tags(unsigned *dst, unsigned *dst_nr, > + unsigned *src, unsigned *src_nr, > + unsigned nr) > +{ > + *src_nr -= nr; > + memcpy(dst + *dst_nr, src + *src_nr, sizeof(unsigned) * nr); > + *dst_nr += nr; > +} > + > +static inline unsigned alloc_local_tag(struct percpu_ida *pool, > + struct percpu_ida_cpu *tags) Pass the __percpu offset and not the tags pointer. > +{ > + int tag = -ENOSPC; > + > + spin_lock(&tags->lock); Interupts are already disabled. Drop the spinlock. > + if (tags->nr_free) > + tag = tags->freelist[...

...tags(unsigned *dst, unsigned *dst_nr, > + unsigned *src, unsigned *src_nr, > + unsigned nr) > +{ > + *src_nr -= nr; > + memcpy(dst + *dst_nr, src + *src_nr, sizeof(unsigned) * nr); > + *dst_nr += nr; > +} > + > +static inline unsigned alloc_local_tag(struct percpu_ida *pool, > + struct percpu_ida_cpu *tags) Pass the __percpu offset and not the tags pointer. > +{ > + int tag = -ENOSPC; > + > + spin_lock(&tags->lock); Interupts are already disabled. Drop the spinlock. > + if (tags->nr_free) > + tag = tags->freelist[...

On Wed, 28 Aug 2013 13:44:54 -0700 Kent Overstreet <kmo at daterainc.com> wrote: > > > > What guarantees that this wait will terminate? > > > > > > It seems fairly clear to me from the break statement a couple lines up; > > > if we were passed __GFP_WAIT we terminate iff we succesfully allocated a > > > tag. If we weren't passed