mm: add vfree_atomic()
We are going to use sleeping lock for freeing vmap. However some
vfree() users want to free memory from atomic (but not from interrupt)
context. For this we add vfree_atomic() - deferred variation of vfree()
which can be used in any atomic context (except NMIs).
[akpm@linux-foundation.org: tweak comment grammar]
[aryabinin@virtuozzo.com: use raw_cpu_ptr() instead of this_cpu_ptr()]
Link: http://lkml.kernel.org/r/1481553981-3856-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1479474236-4139-5-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1f5501b..4ac776f 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1486,7 +1486,39 @@ static void __vunmap(const void *addr, int deallocate_pages)
kfree(area);
return;
}
-
+
+static inline void __vfree_deferred(const void *addr)
+{
+ /*
+ * Use raw_cpu_ptr() because this can be called from preemptible
+ * context. Preemption is absolutely fine here, because the llist_add()
+ * implementation is lockless, so it works even if we are adding to
+ * nother cpu's list. schedule_work() should be fine with this too.
+ */
+ struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred);
+
+ if (llist_add((struct llist_node *)addr, &p->list))
+ schedule_work(&p->wq);
+}
+
+/**
+ * vfree_atomic - release memory allocated by vmalloc()
+ * @addr: memory base address
+ *
+ * This one is just like vfree() but can be called in any atomic context
+ * except NMIs.
+ */
+void vfree_atomic(const void *addr)
+{
+ BUG_ON(in_nmi());
+
+ kmemleak_free(addr);
+
+ if (!addr)
+ return;
+ __vfree_deferred(addr);
+}
+
/**
* vfree - release memory allocated by vmalloc()
* @addr: memory base address
@@ -1509,11 +1541,9 @@ void vfree(const void *addr)
if (!addr)
return;
- if (unlikely(in_interrupt())) {
- struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
- if (llist_add((struct llist_node *)addr, &p->list))
- schedule_work(&p->wq);
- } else
+ if (unlikely(in_interrupt()))
+ __vfree_deferred(addr);
+ else
__vunmap(addr, 1);
}
EXPORT_SYMBOL(vfree);