From: Joel Fernandes <joelaf@google.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>,
Jisheng Zhang <jszhang@marvell.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
John Dias <joaodias@google.com>,
"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
linux-rt-users@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/7] mm: defer vmalloc from atomic context
Date: Fri, 4 Nov 2016 20:43:16 -0700 [thread overview]
Message-ID: <CAJWu+oppRL5kD9qPcdCbFAbEkE7bN+kmrvTuaueVZnY+WtK_tg@mail.gmail.com> (raw)
In-Reply-To: <25c117ae-6d06-9846-6a88-ae6221ad6bfe@virtuozzo.com>
On Mon, Oct 24, 2016 at 8:44 AM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
>
>
> On 10/22/2016 06:17 PM, Christoph Hellwig wrote:
>> We want to be able to use a sleeping lock for freeing vmap to keep
>> latency down. For this we need to use the deferred vfree mechanisms
>> no only from interrupt, but from any atomic context.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>> ---
>> mm/vmalloc.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index a4e2cec..bcc1a64 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1509,7 +1509,7 @@ void vfree(const void *addr)
>>
>> if (!addr)
>> return;
>> - if (unlikely(in_interrupt())) {
>> + if (unlikely(in_atomic())) {
>
> in_atomic() cannot always detect atomic context, thus it shouldn't be used here.
> You can add something like vfree_in_atomic() and use it in atomic call sites.
>
So because in_atomic doesn't work for !CONFIG_PREEMPT kernels, can we
always defer the work in these cases?
So for non-preemptible kernels, we always defer:
if (!IS_ENABLED(CONFIG_PREEMPT) || in_atomic()) {
// defer
}
Is this fine? Or any other ideas?
Thanks,
Joel
next prev parent reply other threads:[~2016-11-05 3:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-22 15:17 reduce latency in __purge_vmap_area_lazy Christoph Hellwig
2016-10-22 15:17 ` [PATCH 1/7] mm: remove free_unmap_vmap_area_noflush Christoph Hellwig
2016-10-22 15:17 ` [PATCH 2/7] mm: remove free_unmap_vmap_area_addr Christoph Hellwig
2016-10-22 15:17 ` [PATCH 3/7] mm: refactor __purge_vmap_area_lazy Christoph Hellwig
2016-10-22 15:17 ` [PATCH 4/7] mm: defer vmalloc from atomic context Christoph Hellwig
2016-10-24 15:44 ` Andrey Ryabinin
2016-11-05 3:43 ` Joel Fernandes [this message]
2016-11-07 15:01 ` Andrey Ryabinin
2016-11-07 15:09 ` Christoph Hellwig
2016-11-08 15:03 ` Andrey Ryabinin
2016-11-08 15:05 ` [PATCH 1/3] mm/vmalloc: add vfree_atomic() Andrey Ryabinin
2016-11-08 15:05 ` [PATCH 2/3] kernel/fork: use vfree_atomic() to free thread stack Andrey Ryabinin
2016-11-08 15:05 ` [PATCH 3/3] x86/ldt: use vfree_atomic() to free ldt entries Andrey Ryabinin
2016-11-07 16:50 ` [PATCH 4/7] mm: defer vmalloc from atomic context Joel Fernandes
2016-10-22 15:17 ` [PATCH 5/7] mm: mark all calls into the vmalloc subsystem as potentially sleeping Christoph Hellwig
2016-10-22 15:17 ` [PATCH 6/7] mm: turn vmap_purge_lock into a mutex Christoph Hellwig
2016-10-22 15:17 ` [PATCH 7/7] mm: add preempt points into __purge_vmap_area_lazy Christoph Hellwig
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