similar to: [PATCH-v3 0/4] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12

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

On Fri, 16 Aug 2013 23:09:06 +0000 "Nicholas A. Bellinger" <nab at linux-iscsi.org> wrote: > From: Kent Overstreet <kmo at daterainc.com> > > Percpu frontend for allocating ids. With percpu allocation (that works), > it's impossible to guarantee it will always be possible to allocate all > nr_tags - typically, some will be stuck on a remote percpu

On Fri, 16 Aug 2013 23:09:06 +0000 "Nicholas A. Bellinger" <nab at linux-iscsi.org> wrote: > From: Kent Overstreet <kmo at daterainc.com> > > Percpu frontend for allocating ids. With percpu allocation (that works), > it's impossible to guarantee it will always be possible to allocate all > nr_tags - typically, some will be stuck on a remote percpu

On Fri, 16 Aug 2013, Nicholas A. Bellinger wrote: > + spinlock_t lock; Remove the spinlock. > + unsigned nr_free; > + unsigned freelist[]; > +}; > + > +static inline void move_tags(unsigned *dst, unsigned *dst_nr, > + unsigned *src, unsigned *src_nr, > + unsigned nr) > +{ > + *src_nr -= nr; > + memcpy(dst + *dst_nr, src + *src_nr,

On Fri, 16 Aug 2013, Nicholas A. Bellinger wrote: > + spinlock_t lock; Remove the spinlock. > + unsigned nr_free; > + unsigned freelist[]; > +}; > + > +static inline void move_tags(unsigned *dst, unsigned *dst_nr, > + unsigned *src, unsigned *src_nr, > + unsigned nr) > +{ > + *src_nr -= nr; > + memcpy(dst + *dst_nr, src + *src_nr,

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 in-flight per-cpu ida bits here: [PATCH v3] lib/idr.c rewrite, percpu ida/tag allocator http://marc.info/?l=linux-kernel&m=137308733526328&w=2 Patch #1 includes target-core setup of

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 in-flight per-cpu ida bits here: [PATCH v3] lib/idr.c rewrite, percpu ida/tag allocator http://marc.info/?l=linux-kernel&m=137308733526328&w=2 Patch #1 includes target-core setup of

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 > >

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 > >

From: Kent Overstreet <kmo at daterainc.com> Percpu frontend for allocating ids. With percpu allocation (that works), it's impossible to guarantee it will always be possible to allocate all nr_tags - typically, some will be stuck on a remote percpu freelist where the current job can't get to them. We do guarantee that it will always be possible to allocate at least (nr_tags / 2)

Fixup patch, addressing Andrew's review feedback: Signed-off-by: Kent Overstreet <kmo at daterainc.com> --- include/linux/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 +++

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. > > +

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

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

On Tue, 2018-06-12 at 09:15 -0700, Matthew Wilcox wrote: > On Tue, Jun 12, 2018 at 03:22:42PM +0000, Bart Van Assche wrote: > > On Tue, 2018-05-15 at 09:00 -0700, Matthew Wilcox wrote: > > > diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c > > > index 025dc2d3f3de..cdf671c2af61 100644 > > > ---

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi folks, The following is the RFC-v3 series of tcm_vhost target fabric driver code currently in-flight for-3.6 mainline code. With the merge window opening soon, the tcm_vhost code has started seeing time in linux-next. The v2 -> v3 changelog from the last week is currently looking like: *) Unlock on error in tcm_vhost_drop_nexus()

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi folks, The following is the RFC-v3 series of tcm_vhost target fabric driver code currently in-flight for-3.6 mainline code. With the merge window opening soon, the tcm_vhost code has started seeing time in linux-next. The v2 -> v3 changelog from the last week is currently looking like: *) Unlock on error in tcm_vhost_drop_nexus()

From: Nicholas Bellinger <nab at linux-iscsi.org> Hi folks, The following is a RFC-v2 series of tcm_vhost target fabric driver code currently in-flight for-3.6 mainline code. After last week's developments along with the help of some new folks, the changelog v1 -> v2 so far looks like: *) Fix drivers/vhost/test.c to use VHOST_NET_FEATURES in patch #1 (Asias He) *) Fix tv_cmd