Displaying 13 results from an estimated 13 matches for "steal_tags".
2013 Aug 20
5
[PATCH-v3 1/4] idr: Percpu ida
...freelists. On allocation failure if
> enough cpus have tags that there could potentially be (nr_tags / 2) tags
> stuck on remote percpu freelists, we then pick a remote cpu at random to
> steal from.
>
> Note that there's no cpu hotplug notifier - we don't care, because
> steal_tags() will eventually get the down cpu's tags. We _could_ satisfy
> more allocations if we had a notifier - but we'll still meet our
> guarantees and it's absolutely not a correctness issue, so I don't think
> it's worth the extra code.
>
> ...
>
> include/linu...
2013 Aug 20
5
[PATCH-v3 1/4] idr: Percpu ida
...freelists. On allocation failure if
> enough cpus have tags that there could potentially be (nr_tags / 2) tags
> stuck on remote percpu freelists, we then pick a remote cpu at random to
> steal from.
>
> Note that there's no cpu hotplug notifier - we don't care, because
> steal_tags() will eventually get the down cpu's tags. We _could_ satisfy
> more allocations if we had a notifier - but we'll still meet our
> guarantees and it's absolutely not a correctness issue, so I don't think
> it's worth the extra code.
>
> ...
>
> include/linu...
2013 Aug 28
0
[PATCH-v3 1/4] idr: Percpu ida
On Tue, Aug 20, 2013 at 02:31:57PM -0700, Andrew Morton wrote:
> On Fri, 16 Aug 2013 23:09:06 +0000 "Nicholas A. Bellinger" <nab at linux-iscsi.org> wrote:
> > + /*
> > + * 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 bitmap _must_ be set whenever a
> > + * percpu...
2013 Aug 16
0
[PATCH-v3 1/4] idr: Percpu ida
...pus have tags on their percpu freelists. On allocation failure if
enough cpus have tags that there could potentially be (nr_tags / 2) tags
stuck on remote percpu freelists, we then pick a remote cpu at random to
steal from.
Note that there's no cpu hotplug notifier - we don't care, because
steal_tags() will eventually get the down cpu's tags. We _could_ satisfy
more allocations if we had a notifier - but we'll still meet our
guarantees and it's absolutely not a correctness issue, so I don't think
it's worth the extra code.
Signed-off-by: Kent Overstreet <koverstreet at g...
2013 Aug 28
2
[PATCH-v3 1/4] idr: Percpu ida
On Wed, 28 Aug 2013 12:53:17 -0700 Kent Overstreet <kmo at daterainc.com> wrote:
> > > + while (1) {
> > > + spin_lock(&pool->lock);
> > > +
> > > + /*
> > > + * prepare_to_wait() must come before steal_tags(), in case
> > > + * percpu_ida_free() on another cpu flips a bit in
> > > + * cpus_have_tags
> > > + *
> > > + * global lock held and irqs disabled, don't need percpu lock
> > > + */
> > > + prepare_to_wait(&pool->wait, &a...
2013 Aug 28
2
[PATCH-v3 1/4] idr: Percpu ida
On Wed, 28 Aug 2013 12:53:17 -0700 Kent Overstreet <kmo at daterainc.com> wrote:
> > > + while (1) {
> > > + spin_lock(&pool->lock);
> > > +
> > > + /*
> > > + * prepare_to_wait() must come before steal_tags(), in case
> > > + * percpu_ida_free() on another cpu flips a bit in
> > > + * cpus_have_tags
> > > + *
> > > + * global lock held and irqs disabled, don't need percpu lock
> > > + */
> > > + prepare_to_wait(&pool->wait, &a...
2013 Aug 16
6
[PATCH-v3 0/4] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12
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
2013 Aug 16
6
[PATCH-v3 0/4] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12
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
2013 Aug 28
0
[PATCH-v3 1/4] idr: Percpu ida
...ote:
> On Wed, 28 Aug 2013 12:53:17 -0700 Kent Overstreet <kmo at daterainc.com> wrote:
>
> > > > + while (1) {
> > > > + spin_lock(&pool->lock);
> > > > +
> > > > + /*
> > > > + * prepare_to_wait() must come before steal_tags(), in case
> > > > + * percpu_ida_free() on another cpu flips a bit in
> > > > + * cpus_have_tags
> > > > + *
> > > > + * global lock held and irqs disabled, don't need percpu lock
> > > > + */
> > > > + prepare_...
2013 Aug 28
0
[PATCH] percpu ida: Switch to cpumask_t, add some comments
...3) / 2)
struct percpu_ida_cpu {
+ /*
+ * Even though this is percpu, we need a lock for tag stealing by remote
+ * CPUs:
+ */
spinlock_t lock;
+
+ /* nr_free/freelist form a stack of free IDs */
unsigned nr_free;
unsigned freelist[];
};
@@ -1209,21 +1215,21 @@ static inline void steal_tags(struct percpu_ida *pool,
unsigned cpus_have_tags, cpu = pool->cpu_last_stolen;
struct percpu_ida_cpu *remote;
- for (cpus_have_tags = bitmap_weight(pool->cpus_have_tags, nr_cpu_ids);
+ for (cpus_have_tags = cpumask_weight(&pool->cpus_have_tags);
cpus_have_tags * IDA_PCPU_S...
2018 Jun 12
8
[PATCH 0/3] Use sbitmap instead of percpu_ida
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
2018 Jun 12
8
[PATCH 0/3] Use sbitmap instead of percpu_ida
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
2018 May 15
6
[PATCH 0/2] Use sbitmap instead of 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