On 2015/06/04 22:04, Xishi Qiu wrote:
Add the buddy system interface for address range mirroring feature.
Allocate mirrored pages in MIGRATE_MIRROR list. If there is no mirrored pages
left, use other types pages.
Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
---
mm/page_alloc.c | 40 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d4d2066..0fb55288 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -599,6 +599,26 @@ static inline bool is_mirror_pfn(unsigned long pfn)
return false;
}
+
+static inline bool change_to_mirror(gfp_t gfp_flags, int high_zoneidx)
+{
+ /*
+ * Do not alloc mirrored memory below 4G, because 0-4G is
+ * all mirrored by default, and the list is always empty.
+ */
+ if (high_zoneidx < ZONE_NORMAL)
+ return false;
+
+ /* Alloc mirrored memory for only kernel */
+ if (gfp_flags & __GFP_MIRROR)
+ return true;
GFP_KERNEL itself should imply mirror, I think.
+
+ /* Alloc mirrored memory for both user and kernel */
+ if (sysctl_mirrorable)
+ return true;
Reading this, I think this sysctl is not good. The user cannot know what is mirrored
because memory may not be mirrored until the sysctl is set.
Thanks,
-Kame
+
+ return false;
+}
#endif
/*
@@ -1796,7 +1816,10 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
WARN_ON_ONCE(order > 1);
}
spin_lock_irqsave(&zone->lock, flags);
- page = __rmqueue(zone, order, migratetype);
+ if (is_migrate_mirror(migratetype))
+ page = __rmqueue_smallest(zone, order, migratetype);
+ else
+ page = __rmqueue(zone, order, migratetype);
spin_unlock(&zone->lock);
if (!page)
goto failed;
@@ -2928,6 +2951,11 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
+#ifdef CONFIG_MEMORY_MIRROR
+ if (change_to_mirror(gfp_mask, ac.high_zoneidx))
+ ac.migratetype = MIGRATE_MIRROR;
+#endif
+
retry_cpuset:
cpuset_mems_cookie = read_mems_allowed_begin();
@@ -2943,9 +2971,19 @@ retry_cpuset:
/* First allocation attempt */
alloc_mask = gfp_mask|__GFP_HARDWALL;
+retry:
page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
if (unlikely(!page)) {
/*
+ * If there is no mirrored memory, we will alloc other
+ * types memory.
+ */
+ if (is_migrate_mirror(ac.migratetype)) {
+ ac.migratetype = gfpflags_to_migratetype(gfp_mask);
+ goto retry;
+ }
+
+ /*
* Runtime PM, block IO and its error handling path
* can deadlock because I/O on the device might not
* complete.
--
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