Re: [RFCv2 3/3] staging: ion: limit pool size

[Gioh Kim]

2014-10-25 ìì 5:53, Laura Abbott ì ê:
> Hi,
>
> On 10/23/2014 11:47 PM, Gioh Kim wrote:
> > This patch limits pool size by page unit.
>
> This looks useful. Might be nice to add a debugfs option
> to change this at runtime as well.
>
> > Signed-off-by: Gioh Kim <gioh.kim@xxxxxxx>
> > ---
> >   drivers/staging/android/ion/Kconfig         |    4 ++++
> >   drivers/staging/android/ion/ion_page_pool.c |   26 ++++++++++++++++----------
> >   2 files changed, 20 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/staging/android/ion/Kconfig b/drivers/staging/android/ion/Kconfig
> > index 3452346..e6b1a54 100644
> > --- a/drivers/staging/android/ion/Kconfig
> > +++ b/drivers/staging/android/ion/Kconfig
> > @@ -33,3 +33,7 @@ config ION_TEGRA
> >       help
> >         Choose this option if you wish to use ion on an nVidia Tegra.
> >
> > +config ION_POOL_LIMIT
> > +    int "Limit count of pages in pool"
> > +    depends on ION
> > +    default "0"
>
> Can you add help text here? It would be useful to clarify that the
> units are in pages and that 0 will allow unlimited growth of the
> pool. This should also clarify that this is a limit per
> individual pool and not a limit for all page pools in the system.
>
> > diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
> > index 165152f..d63e93f 100644
> > --- a/drivers/staging/android/ion/ion_page_pool.c
> > +++ b/drivers/staging/android/ion/ion_page_pool.c
> > @@ -22,8 +22,11 @@
> >   #include <linux/module.h>
> >   #include <linux/slab.h>
> >   #include <linux/swap.h>
> > +#include <linux/kconfig.h>
> >   #include "ion_priv.h"
> >
> > +#define POOL_LIMIT CONFIG_ION_POOL_LIMIT
> > +
>
> I don't think the extra #define helps anything here, was
> there something else intended here?

No, I just follow other codes.
If it isn't necessary, I will remove it at v2 patch.


> >   static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
> >   {
> >       struct page *page = alloc_pages(pool->gfp_mask, pool->order);
> > @@ -41,8 +44,21 @@ static void ion_page_pool_free_pages(struct ion_page_pool *pool,
> >       __free_pages(page, pool->order);
> >   }
> >
> > +static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
> > +{
> > +    int count = pool->low_count;
> > +
> > +    if (high)
> > +        count += pool->high_count;
> > +
> > +    return count << pool->order;
> > +}
> > +
> >   static int ion_page_pool_add(struct ion_page_pool *pool, struct page *page)
> >   {
> > +    if (POOL_LIMIT && ion_page_pool_total(pool, 1) > POOL_LIMIT)
> > +        return 1;
> > +
> >       mutex_lock(&pool->mutex);
> >       if (PageHighMem(page)) {
> >           list_add_tail(&page->lru, &pool->high_items);
> > @@ -103,16 +119,6 @@ void ion_page_pool_free(struct ion_page_pool *pool, struct page *page)
> >           ion_page_pool_free_pages(pool, page);
> >   }
> >
> > -static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
> > -{
> > -    int count = pool->low_count;
> > -
> > -    if (high)
> > -        count += pool->high_count;
> > -
> > -    return count << pool->order;
> > -}
> > -
> >   int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
> >                   int nr_to_scan)
> >   {
>
> Thanks,
> Laura
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