From: Weijie Yang <weijie.yang.kh@gmail.com>
To: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Weijie Yang <weijie.yang@samsung.com>,
minchan@kernel.org, bob.liu@oracle.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/4] mm/zswap: use GFP_NOIO instead of GFP_KERNEL
Date: Mon, 16 Sep 2013 17:16:52 +0800 [thread overview]
Message-ID: <CAL1ERfNmeMCyUGyjTX4_AV41E_iCJicBoz=w16iSOUp+YKYi8A@mail.gmail.com> (raw)
In-Reply-To: <20130909164750.GC4701@variantweb.net>
On Tue, Sep 10, 2013 at 12:47 AM, Seth Jennings
<sjenning@linux.vnet.ibm.com> wrote:
> On Fri, Sep 06, 2013 at 01:16:45PM +0800, Weijie Yang wrote:
>> To avoid zswap store and reclaim functions called recursively,
>> use GFP_NOIO instead of GFP_KERNEL
>>
>> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
>
> I agree with Bob to some degree that GFP_NOIO is a broadsword here.
> Ideally, we'd like to continue allowing writeback of dirty file pages
> and the like. However, I don't agree that a mutex is the way to do
> this.
>
> My first thought was to use the PF_MEMALLOC task flag, but it is already
> set for kswapd and any task doing direct reclaim. A new task flag would
> work but I'm not sure how acceptable that would be.
as GFP_NOIO is controversial and not the most appropriate method,
I will keep GFP_KERNEL flag until we find a better way to resolve
this problem.
> In the meantime, this does do away with the possibility of very deep
> recursion between the store and reclaim paths.
>
> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
>
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prev parent reply other threads:[~2013-09-16 9:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 5:16 Weijie Yang
2013-09-06 6:41 ` Bob Liu
2013-09-09 16:47 ` Seth Jennings
2013-09-16 9:16 ` Weijie Yang [this message]
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