Xen project Mailing List

Re: [Xen-devel] [PATCH] switch rangeset's lock to rwlock

From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Date: Fri, 19 Sep 2014 12:32:02 -0400

Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Keir Fraser <keir@xxxxxxx>, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>, Tim Deegan <tim@xxxxxxx>

Delivery-date: Fri, 19 Sep 2014 16:32:35 +0000

List-id: Xen developer discussion <xen-devel.lists.xen.org>

On Fri, Sep 12, 2014 at 01:55:07PM +0100, Jan Beulich wrote: > As a general library routine, it should behave as efficiently as > possible, even if at present no significant contention is known here. > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> I am comfortable with this going to Xen 4.5. > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > --- > With the widened use of rangesets I'd like to re-suggest this change > which I had posted already a couple of years back. > > --- a/xen/common/rangeset.c > +++ b/xen/common/rangeset.c > @@ -28,7 +28,7 @@ struct rangeset { > > /* Number of ranges that can be allocated */ > long nr_ranges; > - spinlock_t lock; > + rwlock_t lock; > > /* Pretty-printing name. */ > char name[32]; > @@ -120,7 +120,7 @@ int rangeset_add_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + write_lock(&r->lock); > > x = find_range(r, s); > y = find_range(r, e); > @@ -176,7 +176,7 @@ int rangeset_add_range( > } > > out: > - spin_unlock(&r->lock); > + write_unlock(&r->lock); > return rc; > } > > @@ -188,7 +188,7 @@ int rangeset_remove_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + write_lock(&r->lock); > > x = find_range(r, s); > y = find_range(r, e); > @@ -244,7 +244,7 @@ int rangeset_remove_range( > } > > out: > - spin_unlock(&r->lock); > + write_unlock(&r->lock); > return rc; > } > > @@ -256,10 +256,10 @@ int rangeset_contains_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + read_lock(&r->lock); > x = find_range(r, s); > contains = (x && (x->e >= e)); > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return contains; > } > @@ -272,10 +272,10 @@ int rangeset_overlaps_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + read_lock(&r->lock); > x = find_range(r, e); > overlaps = (x && (s <= x->e)); > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return overlaps; > } > @@ -287,13 +287,13 @@ int rangeset_report_ranges( > struct range *x; > int rc = 0; > > - spin_lock(&r->lock); > + read_lock(&r->lock); > > for ( x = find_range(r, s); x && (x->s <= e) && !rc; x = next_range(r, > x) ) > if ( x->e >= s ) > rc = cb(max(x->s, s), min(x->e, e), ctxt); > > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return rc; > } > @@ -331,7 +331,7 @@ struct rangeset *rangeset_new( > if ( r == NULL ) > return NULL; > > - spin_lock_init(&r->lock); > + rwlock_init(&r->lock); > INIT_LIST_HEAD(&r->range_list); > r->nr_ranges = -1; > > @@ -414,21 +414,21 @@ void rangeset_swap(struct rangeset *a, s > > if ( a < b ) > { > - spin_lock(&a->lock); > - spin_lock(&b->lock); > + write_lock(&a->lock); > + write_lock(&b->lock); > } > else > { > - spin_lock(&b->lock); > - spin_lock(&a->lock); > + write_lock(&b->lock); > + write_lock(&a->lock); > } > > list_splice_init(&a->range_list, &tmp); > list_splice_init(&b->range_list, &a->range_list); > list_splice(&tmp, &b->range_list); > > - spin_unlock(&a->lock); > - spin_unlock(&b->lock); > + write_unlock(&a->lock); > + write_unlock(&b->lock); > } > > /***************************** > @@ -446,7 +446,7 @@ void rangeset_printk( > int nr_printed = 0; > struct range *x; > > - spin_lock(&r->lock); > + read_lock(&r->lock); > > printk("%-10s {", r->name); > > @@ -465,7 +465,7 @@ void rangeset_printk( > > printk(" }"); > > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > } > > void rangeset_domain_printk( > > > > switch rangeset's lock to rwlock > > As a general library routine, it should behave as efficiently as > possible, even if at present no significant contention is known here. > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > --- > With the widened use of rangesets I'd like to re-suggest this change > which I had posted already a couple of years back. > > --- a/xen/common/rangeset.c > +++ b/xen/common/rangeset.c > @@ -28,7 +28,7 @@ struct rangeset { > > /* Number of ranges that can be allocated */ > long nr_ranges; > - spinlock_t lock; > + rwlock_t lock; > > /* Pretty-printing name. */ > char name[32]; > @@ -120,7 +120,7 @@ int rangeset_add_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + write_lock(&r->lock); > > x = find_range(r, s); > y = find_range(r, e); > @@ -176,7 +176,7 @@ int rangeset_add_range( > } > > out: > - spin_unlock(&r->lock); > + write_unlock(&r->lock); > return rc; > } > > @@ -188,7 +188,7 @@ int rangeset_remove_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + write_lock(&r->lock); > > x = find_range(r, s); > y = find_range(r, e); > @@ -244,7 +244,7 @@ int rangeset_remove_range( > } > > out: > - spin_unlock(&r->lock); > + write_unlock(&r->lock); > return rc; > } > > @@ -256,10 +256,10 @@ int rangeset_contains_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + read_lock(&r->lock); > x = find_range(r, s); > contains = (x && (x->e >= e)); > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return contains; > } > @@ -272,10 +272,10 @@ int rangeset_overlaps_range( > > ASSERT(s <= e); > > - spin_lock(&r->lock); > + read_lock(&r->lock); > x = find_range(r, e); > overlaps = (x && (s <= x->e)); > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return overlaps; > } > @@ -287,13 +287,13 @@ int rangeset_report_ranges( > struct range *x; > int rc = 0; > > - spin_lock(&r->lock); > + read_lock(&r->lock); > > for ( x = find_range(r, s); x && (x->s <= e) && !rc; x = next_range(r, > x) ) > if ( x->e >= s ) > rc = cb(max(x->s, s), min(x->e, e), ctxt); > > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > > return rc; > } > @@ -331,7 +331,7 @@ struct rangeset *rangeset_new( > if ( r == NULL ) > return NULL; > > - spin_lock_init(&r->lock); > + rwlock_init(&r->lock); > INIT_LIST_HEAD(&r->range_list); > r->nr_ranges = -1; > > @@ -414,21 +414,21 @@ void rangeset_swap(struct rangeset *a, s > > if ( a < b ) > { > - spin_lock(&a->lock); > - spin_lock(&b->lock); > + write_lock(&a->lock); > + write_lock(&b->lock); > } > else > { > - spin_lock(&b->lock); > - spin_lock(&a->lock); > + write_lock(&b->lock); > + write_lock(&a->lock); > } > > list_splice_init(&a->range_list, &tmp); > list_splice_init(&b->range_list, &a->range_list); > list_splice(&tmp, &b->range_list); > > - spin_unlock(&a->lock); > - spin_unlock(&b->lock); > + write_unlock(&a->lock); > + write_unlock(&b->lock); > } > > /***************************** > @@ -446,7 +446,7 @@ void rangeset_printk( > int nr_printed = 0; > struct range *x; > > - spin_lock(&r->lock); > + read_lock(&r->lock); > > printk("%-10s {", r->name); > > @@ -465,7 +465,7 @@ void rangeset_printk( > > printk(" }"); > > - spin_unlock(&r->lock); > + read_unlock(&r->lock); > } > > void rangeset_domain_printk( > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel

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