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Commit 43948913 authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Vinayak Menon
Browse files

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: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: default avatarChristoph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Git-commit: bf22e37a641327e34681b7b6959d9646e3886770
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Change-Id: I5f67e939774da6e811f3a5180a6b0f5d31fbe32b
Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
parent 0818bc7a

include/linux/vmalloc.h

+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align, 
			const void *caller);



extern void vfree(const void *addr);

extern void vfree_atomic(const void *addr);



extern void *vmap(struct page **pages, unsigned int count,

			unsigned long flags, pgprot_t prot);

mm/vmalloc.c

+36 −6
Original line number Diff line number Diff line
@@ -1554,6 +1554,38 @@ static void __vunmap(const void *addr, int deallocate_pages) 
	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
@@ -1576,11 +1608,9 @@ 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);