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Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c34
1 files changed, 20 insertions, 14 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 98d348347..dddefaeaa 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -48,6 +48,12 @@ static void free_swap_count_continuations(struct swap_info_struct *);
DEFINE_SPINLOCK(swap_lock);
static unsigned int nr_swapfiles;
atomic_long_t nr_swap_pages;
+/*
+ * Some modules use swappable objects and may try to swap them out under
+ * memory pressure (via the shrinker). Before doing so, they may wish to
+ * check to see if any swap space is available.
+ */
+EXPORT_SYMBOL_GPL(nr_swap_pages);
/* protected with swap_lock. reading in vm_swap_full() doesn't need lock */
long total_swap_pages;
static int least_priority;
@@ -113,7 +119,7 @@ __try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset)
ret = try_to_free_swap(page);
unlock_page(page);
}
- page_cache_release(page);
+ put_page(page);
return ret;
}
@@ -970,18 +976,19 @@ out:
* to it. And as a side-effect, free up its swap: because the old content
* on disk will never be read, and seeking back there to write new content
* later would only waste time away from clustering.
+ *
+ * NOTE: total_mapcount should not be relied upon by the caller if
+ * reuse_swap_page() returns false, but it may be always overwritten
+ * (see the other implementation for CONFIG_SWAP=n).
*/
-int reuse_swap_page(struct page *page)
+bool reuse_swap_page(struct page *page, int *total_mapcount)
{
int count;
VM_BUG_ON_PAGE(!PageLocked(page), page);
if (unlikely(PageKsm(page)))
- return 0;
- /* The page is part of THP and cannot be reused */
- if (PageTransCompound(page))
- return 0;
- count = page_mapcount(page);
+ return false;
+ count = page_trans_huge_mapcount(page, total_mapcount);
if (count <= 1 && PageSwapCache(page)) {
count += page_swapcount(page);
if (count == 1 && !PageWriteback(page)) {
@@ -1048,7 +1055,7 @@ int free_swap_and_cache(swp_entry_t entry)
page = find_get_page(swap_address_space(entry),
entry.val);
if (page && !trylock_page(page)) {
- page_cache_release(page);
+ put_page(page);
page = NULL;
}
}
@@ -1065,7 +1072,7 @@ int free_swap_and_cache(swp_entry_t entry)
SetPageDirty(page);
}
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
}
return p != NULL;
}
@@ -1566,7 +1573,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
}
if (retval) {
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
break;
}
@@ -1618,7 +1625,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
*/
SetPageDirty(page);
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
/*
* Make sure that we aren't completely killing
@@ -2580,8 +2587,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
(swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT;
enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map);
- pr_info("Adding %uk swap on %s. "
- "Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",
+ pr_info("Adding %uk swap on %s. Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",
p->pages<<(PAGE_SHIFT-10), name->name, p->prio,
nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
(p->flags & SWP_SOLIDSTATE) ? "SS" : "",
@@ -2623,7 +2629,7 @@ bad_swap:
out:
if (page && !IS_ERR(page)) {
kunmap(page);
- page_cache_release(page);
+ put_page(page);
}
if (name)
putname(name);