From: Michal Hocko <mhocko@kernel.org>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: akpm@linux-foundation.org, penguin-kernel@I-love.SAKURA.ne.jp,
linux-kernel@vger.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,
willy@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH 4/4] mm/vmalloc: remove vfree_atomic()
Date: Tue, 4 Apr 2017 11:40:50 +0200 [thread overview]
Message-ID: <20170404094049.GI15132@dhcp22.suse.cz> (raw)
In-Reply-To: <20170330102719.13119-4-aryabinin@virtuozzo.com>
On Thu 30-03-17 13:27:19, Andrey Ryabinin wrote:
> vfree() can be used in any atomic context and there is no
> vfree_atomic() callers left, so let's remove it.
>
> This reverts commit bf22e37a6413 ("mm: add vfree_atomic()")
>
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
the idea was nice but reality hits the fan and we learn that this just
doesn't work...
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> include/linux/vmalloc.h | 1 -
> mm/vmalloc.c | 40 +++++-----------------------------------
> 2 files changed, 5 insertions(+), 36 deletions(-)
>
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 46991ad..b4f044f 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -83,7 +83,6 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
> extern void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags);
>
> 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);
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index ea1b4ab..b77337a 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1534,38 +1534,6 @@ 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
> @@ -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);
> --
> 2.10.2
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-04-04 9:40 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
2017-03-30 15:27 ` Andrey Ryabinin
2017-04-04 9:40 ` Michal Hocko [this message]
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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