Hi Dan,
On Thu, Aug 21, 2014 at 02:53:57PM -0400, Dan Streetman wrote:
> On Wed, Aug 20, 2014 at 8:27 PM, Minchan Kim <minchan@xxxxxxxxxx> wrote:
> > zs_get_total_size_bytes returns a amount of memory zsmalloc
> > consumed with *byte unit* but zsmalloc operates *page unit*
> > rather than byte unit so let's change the API so benefit
> > we could get is that reduce unnecessary overhead
> > (ie, change page unit with byte unit) in zsmalloc.
> >
> > Now, zswap can rollback to zswap_pool_pages.
> > Over to zswap guys ;-)
>
> We could change zpool/zswap over to total pages instead of total
> bytes, since both zbud and zsmalloc now report size in pages. The
> only downside would be if either changed later to not use only whole
> pages (or if they start using huge pages for storage...), but for what
> they do that seems unlikely. After this patch is finalized I can
> write up a quick patch unless Seth disagrees (or already has a patch
> :)
That's extactly what I mentioned zswap in this patch.
Now that you guys notice my intention, I will remove zswap part in
description in next revision.
Thanks.
>
> >
> > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> > ---
> > drivers/block/zram/zram_drv.c | 4 ++--
> > include/linux/zsmalloc.h | 2 +-
> > mm/zsmalloc.c | 10 +++++-----
> > 3 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > index d00831c3d731..302dd37bcea3 100644
> > --- a/drivers/block/zram/zram_drv.c
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -103,10 +103,10 @@ static ssize_t mem_used_total_show(struct device *dev,
> >
> > down_read(&zram->init_lock);
> > if (init_done(zram))
> > - val = zs_get_total_size_bytes(meta->mem_pool);
> > + val = zs_get_total_size(meta->mem_pool);
> > up_read(&zram->init_lock);
> >
> > - return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
> > + return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
> > }
> >
> > static ssize_t max_comp_streams_show(struct device *dev,
> > diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
> > index e44d634e7fb7..105b56e45d23 100644
> > --- a/include/linux/zsmalloc.h
> > +++ b/include/linux/zsmalloc.h
> > @@ -46,6 +46,6 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
> > enum zs_mapmode mm);
> > void zs_unmap_object(struct zs_pool *pool, unsigned long handle);
> >
> > -u64 zs_get_total_size_bytes(struct zs_pool *pool);
> > +unsigned long zs_get_total_size(struct zs_pool *pool);
>
> minor naming suggestion, but since the name is changing anyway,
> "zs_get_total_size" implies to me the units are bytes, would
> "zs_get_total_pages" be clearer that it's returning size in # of
> pages, not bytes?
>
> >
> > #endif
> > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> > index a65924255763..80408a1da03a 100644
> > --- a/mm/zsmalloc.c
> > +++ b/mm/zsmalloc.c
> > @@ -299,7 +299,7 @@ static void zs_zpool_unmap(void *pool, unsigned long handle)
> >
> > static u64 zs_zpool_total_size(void *pool)
> > {
> > - return zs_get_total_size_bytes(pool);
> > + return zs_get_total_size(pool) << PAGE_SHIFT;
> > }
> >
> > static struct zpool_driver zs_zpool_driver = {
> > @@ -1186,16 +1186,16 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
> > }
> > EXPORT_SYMBOL_GPL(zs_unmap_object);
> >
> > -u64 zs_get_total_size_bytes(struct zs_pool *pool)
> > +unsigned long zs_get_total_size(struct zs_pool *pool)
> > {
> > - u64 npages;
> > + unsigned long npages;
> >
> > spin_lock(&pool->stat_lock);
> > npages = pool->pages_allocated;
> > spin_unlock(&pool->stat_lock);
> > - return npages << PAGE_SHIFT;
> > + return npages;
> > }
> > -EXPORT_SYMBOL_GPL(zs_get_total_size_bytes);
> > +EXPORT_SYMBOL_GPL(zs_get_total_size);
> >
> > module_init(zs_init);
> > module_exit(zs_exit);
> > --
> > 2.0.0
> >
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