Re: [PATCH] mm/swap: add function get_total_swap_pages to expose total_swap_pages

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Roger,

I think this patch isn't need at all. You can directly read total_swap_pages variable in TTM. See the comment:

/* protected with swap_lock. reading in vm_swap_full() doesn't need lock */
long total_swap_pages;

there are many places using it directly, you just couldn't change its value. Reading it doesn't need lock.


Regards,

David Zhou


On 2018年01月29日 16:29, Roger He wrote:
ttm module needs it to determine its internal parameter setting.

Signed-off-by: Roger He <Hongbo.He@xxxxxxx>
---
  include/linux/swap.h |  6 ++++++
  mm/swapfile.c        | 15 +++++++++++++++
  2 files changed, 21 insertions(+)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index c2b8128..708d66f 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -484,6 +484,7 @@ extern int try_to_free_swap(struct page *);
  struct backing_dev_info;
  extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
  extern void exit_swap_address_space(unsigned int type);
+extern long get_total_swap_pages(void);
#else /* CONFIG_SWAP */ @@ -516,6 +517,11 @@ static inline void show_swap_cache_info(void)
  {
  }
+long get_total_swap_pages(void)
+{
+	return 0;
+}
+
  #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
  #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 3074b02..a0062eb 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -98,6 +98,21 @@ static atomic_t proc_poll_event = ATOMIC_INIT(0);
atomic_t nr_rotate_swap = ATOMIC_INIT(0); +/*
+ * expose this value for others use
+ */
+long get_total_swap_pages(void)
+{
+	long ret;
+
+	spin_lock(&swap_lock);
+	ret = total_swap_pages;
+	spin_unlock(&swap_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_total_swap_pages);
+
  static inline unsigned char swap_count(unsigned char ent)
  {
  	return ent & ~SWAP_HAS_CACHE;	/* may include SWAP_HAS_CONT flag */

_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux