On Mon, Jul 04, 2016 at 09:03:18AM +0900, Minchan Kim wrote:
> On Fri, Jul 01, 2016 at 02:41:03PM +0800, Ganesh Mahendran wrote:
> > Currently, if a class can not be merged, the max objects of zspage
> > in that class may be calculated twice.
> >
> > This patch calculate max objects of zspage at the begin, and pass
> > the value to can_merge() to decide whether the class can be merged.
> >
> > Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx>
> > ---
> > mm/zsmalloc.c | 21 ++++++++++-----------
> > 1 file changed, 10 insertions(+), 11 deletions(-)
> >
> > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> > index 50283b1..2690914 100644
> > --- a/mm/zsmalloc.c
> > +++ b/mm/zsmalloc.c
> > @@ -1362,16 +1362,14 @@ static void init_zs_size_classes(void)
> > zs_size_classes = nr;
> > }
> >
> > -static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
> > +static bool can_merge(struct size_class *prev, int pages_per_zspage,
> > + int objs_per_zspage)
> > {
> > - if (prev->pages_per_zspage != pages_per_zspage)
> > - return false;
> > -
> > - if (prev->objs_per_zspage
> > - != get_maxobj_per_zspage(size, pages_per_zspage))
> > - return false;
> > + if (prev->pages_per_zspage == pages_per_zspage &&
> > + prev->objs_per_zspage == objs_per_zspage)
> > + return true;
> >
> > - return true;
> > + return false;
> > }
> >
> > static bool zspage_full(struct size_class *class, struct zspage *zspage)
> > @@ -2460,6 +2458,7 @@ struct zs_pool *zs_create_pool(const char *name)
> > for (i = zs_size_classes - 1; i >= 0; i--) {
> > int size;
> > int pages_per_zspage;
> > + int objs_per_zspage;
> > struct size_class *class;
> > int fullness = 0;
> >
> > @@ -2467,6 +2466,7 @@ struct zs_pool *zs_create_pool(const char *name)
> > if (size > ZS_MAX_ALLOC_SIZE)
> > size = ZS_MAX_ALLOC_SIZE;
> > pages_per_zspage = get_pages_per_zspage(size);
> > + objs_per_zspage = get_maxobj_per_zspage(size, pages_per_zspage);
>
> So, user of get_maxobj_per_zspage is only here? If so, let's remove
> get_maxobj_per_zspage to prevent misuse in future. Instead, use open code
> here.
Yes, get_maxobj_per_zspage is only called here.
I will remove it in V2.
Thanks.
>
>
> >
> > /*
> > * size_class is used for normal zsmalloc operation such
> > @@ -2478,7 +2478,7 @@ struct zs_pool *zs_create_pool(const char *name)
> > * previous size_class if possible.
> > */
> > if (prev_class) {
> > - if (can_merge(prev_class, size, pages_per_zspage)) {
> > + if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
> > pool->size_class[i] = prev_class;
> > continue;
> > }
> > @@ -2491,8 +2491,7 @@ struct zs_pool *zs_create_pool(const char *name)
> > class->size = size;
> > class->index = i;
> > class->pages_per_zspage = pages_per_zspage;
> > - class->objs_per_zspage = get_maxobj_per_zspage(class->size,
> > - class->pages_per_zspage);
> > + class->objs_per_zspage = objs_per_zspage;
> > spin_lock_init(&class->lock);
> > pool->size_class[i] = class;
> > for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
> > --
> > 1.9.1
> >
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