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authorChris Wilson <chris@chris-wilson.co.uk>2016-04-04 14:46:42 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2016-04-05 11:12:04 +0100
commit4da56b99d99e5a7df2b7f11e87bfea935f909732 (patch)
treeecbc153fc497ab54bc191a9973bea98fac34af35 /mm/vmalloc.c
parent6f0ac2047a86a0ce3d75227f8b83e84d0a2f993d (diff)
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mm/vmap: Add a notifier for when we run out of vmap address space
vmaps are temporary kernel mappings that may be of long duration. Reusing a vmap on an object is preferrable for a driver as the cost of setting up the vmap can otherwise dominate the operation on the object. However, the vmap address space is rather limited on 32bit systems and so we add a notification for vmap pressure in order for the driver to release any cached vmappings. The interface is styled after the oom-notifier where the callees are passed a pointer to an unsigned long counter for them to indicate if they have freed any space. v2: Guard the blocking notifier call with gfpflags_allow_blocking() v3: Correct typo in forward declaration and move to head of file Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Roman Peniaev <r.peniaev@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Acked-by: Andrew Morton <akpm@linux-foundation.org> # for inclusion via DRM Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1459777603-23618-3-git-send-email-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Diffstat (limited to 'mm/vmalloc.c')
-rw-r--r--mm/vmalloc.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index fb42a5bffe47..12d27ac303ae 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -21,6 +21,7 @@
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/list.h>
+#include <linux/notifier.h>
#include <linux/rbtree.h>
#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
@@ -344,6 +345,8 @@ static void __insert_vmap_area(struct vmap_area *va)
static void purge_vmap_area_lazy(void);
+static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
+
/*
* Allocate a region of KVA of the specified size and alignment, within the
* vstart and vend.
@@ -363,6 +366,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
BUG_ON(offset_in_page(size));
BUG_ON(!is_power_of_2(align));
+ might_sleep_if(gfpflags_allow_blocking(gfp_mask));
+
va = kmalloc_node(sizeof(struct vmap_area),
gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!va))
@@ -468,6 +473,16 @@ overflow:
purged = 1;
goto retry;
}
+
+ if (gfpflags_allow_blocking(gfp_mask)) {
+ unsigned long freed = 0;
+ blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
+ if (freed > 0) {
+ purged = 0;
+ goto retry;
+ }
+ }
+
if (printk_ratelimit())
pr_warn("vmap allocation for size %lu failed: "
"use vmalloc=<size> to increase size.\n", size);
@@ -475,6 +490,18 @@ overflow:
return ERR_PTR(-EBUSY);
}
+int register_vmap_purge_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&vmap_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
+
+int unregister_vmap_purge_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
+
static void __free_vmap_area(struct vmap_area *va)
{
BUG_ON(RB_EMPTY_NODE(&va->rb_node));