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From: Matthew Wilcox <willy@infradead.org>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: akpm@linux-foundation.org, penguin-kernel@I-love.SAKURA.ne.jp,
	linux-kernel@vger.kernel.org, mhocko@kernel.org,
	linux-mm@kvack.org, hpa@zytor.com, chris@chris-wilson.co.uk,
	hch@lst.de, mingo@elte.hu, jszhang@marvell.com,
	joelaf@google.com, joaodias@google.com, tglx@linutronix.de
Subject: Re: [PATCH 4/4] mm/vmalloc: remove vfree_atomic()
Date: Thu, 30 Mar 2017 10:18:46 -0700	[thread overview]
Message-ID: <20170330171845.GA19841@bombadil.infradead.org> (raw)
In-Reply-To: <20170330102719.13119-4-aryabinin@virtuozzo.com>

On Thu, Mar 30, 2017 at 01:27:19PM +0300, Andrey Ryabinin wrote:
> vfree() can be used in any atomic context and there is no
> vfree_atomic() callers left, so let's remove it.

We might still get warnings though.

> @@ -1588,9 +1556,11 @@ void vfree(const void *addr)
>  
>  	if (!addr)
>  		return;
> -	if (unlikely(in_interrupt()))
> -		__vfree_deferred(addr);
> -	else
> +	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
>  		__vunmap(addr, 1);
>  }
>  EXPORT_SYMBOL(vfree);

If I disable preemption, then call vfree(), in_interrupt() will not be
true (I've only incremented preempt_count()), then __vunmap() calls
remove_vm_area() which calls might_sleep(), which will warn.

So I think this check needs to change from in_interrupt() to in_atomic().

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  reply	other threads:[~2017-03-30 17:18 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-30 10:27 [PATCH 1/4] mm/vmalloc: allow to call vfree() in atomic context Andrey Ryabinin
2017-03-30 10:27 ` [PATCH 2/4] x86/ldt: use vfree() instead of vfree_atomic() Andrey Ryabinin
2017-03-31  8:05   ` Thomas Gleixner
2017-03-30 10:27 ` [PATCH 3/4] kernel/fork: use vfree() instead of vfree_atomic() to free thread stack Andrey Ryabinin
2017-03-30 10:27 ` [PATCH 4/4] mm/vmalloc: remove vfree_atomic() Andrey Ryabinin
2017-03-30 17:18   ` Matthew Wilcox [this message]
2017-03-30 15:27     ` Andrey Ryabinin
2017-04-04  9:40   ` Michal Hocko
2017-03-30 12:00 ` [PATCH 1/4] mm/vmalloc: allow to call vfree() in atomic context Thomas Hellstrom
2017-03-30 14:48   ` Andrey Ryabinin
2017-03-30 15:04     ` Thomas Hellstrom
2017-04-04  9:41     ` Michal Hocko
2017-04-04  9:49       ` Thomas Hellstrom
2017-04-05 10:31       ` Andrey Ryabinin
2017-04-05 10:42         ` Michal Hocko
2017-04-05 11:42     ` Vlastimil Babka
2017-04-05 12:14       ` Michal Hocko
2017-03-30 22:22 ` Andrew Morton
2017-03-31  7:12   ` Joel Fernandes
2017-03-31  9:26   ` Andrey Ryabinin
2017-04-04  9:36   ` Michal Hocko
2017-04-04  9:38 ` Michal Hocko
2017-04-12 12:49 ` [PATCH v2 0/5] " Andrey Ryabinin
2017-04-12 12:49   ` [PATCH v2 1/5] mm/vmalloc: " Andrey Ryabinin
2017-04-12 12:49   ` [PATCH v2 2/5] x86/ldt: use vfree() instead of vfree_atomic() Andrey Ryabinin
2017-04-12 12:49   ` [PATCH v2 3/5] kernel/fork: use vfree() instead of vfree_atomic() to free thread stack Andrey Ryabinin
2017-04-12 12:49   ` [PATCH v2 4/5] mm/vmalloc: remove vfree_atomic() Andrey Ryabinin
2017-04-12 12:49   ` [PATCH v2 5/5] mm/vmalloc: Don't spawn workers if somebody already purging Andrey Ryabinin

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