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....@lge.com>
---
  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?

  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

--
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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