search for: tag_cpu

...> > +/* 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 decide when to steal tags, and which cpus > + * to try stealing from. > + * > + * It's ok for a freelist to be empty when its bit is set - steal_tags() >...

...> > +/* 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 decide when to steal tags, and which cpus > + * to try stealing from. > + * > + * It's ok for a freelist to be empty when its bit is set - steal_tags() >...

...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 decide when to steal tags, and which cpus + * to try stealing from. + * + * It's ok for a freelist to be empty when its bit is set - steal_tags() + * will just keep looking - but the b...

...+ * Will not fail if passed __GFP_WAIT. > + */ > +int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) > +{ > + DEFINE_WAIT(wait); > + struct percpu_ida_cpu *tags; > + unsigned long flags; > + int tag; > + > + local_irq_save(flags); > + tags = this_cpu_ptr(pool->tag_cpu); You could drop this_cpu_ptr if you pass pool->tag_cpu to alloc_local_tag. > +/** > + * percpu_ida_free - free a tag > + * @pool: pool @tag was allocated from > + * @tag: a tag previously allocated with percpu_ida_alloc() > + * > + * Safe to be called from interrupt context....

...+ * Will not fail if passed __GFP_WAIT. > + */ > +int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) > +{ > + DEFINE_WAIT(wait); > + struct percpu_ida_cpu *tags; > + unsigned long flags; > + int tag; > + > + local_irq_save(flags); > + tags = this_cpu_ptr(pool->tag_cpu); You could drop this_cpu_ptr if you pass pool->tag_cpu to alloc_local_tag. > +/** > + * percpu_ida_free - free a tag > + * @pool: pool @tag was allocated from > + * @tag: a tag previously allocated with percpu_ida_alloc() > + * > + * Safe to be called from interrupt context....

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

...== nr_cpu_ids) - cpu = find_first_bit(pool->cpus_have_tags, nr_cpu_ids); + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(&pool->cpus_have_tags); - if (cpu == nr_cpu_ids) + if (cpu >= nr_cpu_ids) BUG(); pool->cpu_last_stolen = cpu; remote = per_cpu_ptr(pool->tag_cpu, cpu); - clear_bit(cpu, pool->cpus_have_tags); + cpumask_clear_cpu(cpu, &pool->cpus_have_tags); if (remote == tags) continue; @@ -1246,6 +1252,10 @@ static inline void steal_tags(struct percpu_ida *pool, } } +/* + * Pop up to IDA_PCPU_BATCH_MOVE IDs off the global freeli...

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 in iscsit_wait_for_tag() - Abstracted out tag freeing as requested by Bart

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 in iscsit_wait_for_tag() - Abstracted out tag freeing as requested by Bart

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

...gt; > > + local_irq_restore(flags); > > > + > > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > > + break; > > > + > > > + schedule(); > > > + > > > + local_irq_save(flags); > > > + tags = this_cpu_ptr(pool->tag_cpu); > > > + } > > > > 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 __GFP_WAIT we...

...gt; > > + local_irq_restore(flags); > > > + > > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > > + break; > > > + > > > + schedule(); > > > + > > > + local_irq_save(flags); > > > + tags = this_cpu_ptr(pool->tag_cpu); > > > + } > > > > 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 __GFP_WAIT we...

...t; > + spin_unlock(&pool->lock); > > + local_irq_restore(flags); > > + > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > + break; > > + > > + schedule(); > > + > > + local_irq_save(flags); > > + tags = this_cpu_ptr(pool->tag_cpu); > > + } > > 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 __GFP_WAIT we never actually sleep. I can add a...

...); > > > > + > > > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > > > + break; > > > > + > > > > + schedule(); > > > > + > > > > + local_irq_save(flags); > > > > + tags = this_cpu_ptr(pool->tag_cpu); > > > > + } > > > > > > 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 w...