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From: Igor Stoppa <igor.stoppa@huawei.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: <namhyung@kernel.org>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>
Subject: Question on ___GFP_NOLOCKDEP - Was: Re: [PATCH 1/1] Remove hardcoding of ___GFP_xxx bitmasks
Date: Thu, 27 Apr 2017 15:18:58 +0300	[thread overview]
Message-ID: <66c4a94a-eb55-8d31-f975-aee49778ceb4@huawei.com> (raw)
In-Reply-To: <e3fe4d80-10a8-2008-1798-af3893fe418a@huawei.com>

On 26/04/17 18:29, Igor Stoppa wrote:

> On 26/04/17 17:47, Michal Hocko wrote:

[...]

>> Also the current mm tree has ___GFP_NOLOCKDEP which is not addressed
>> here so I suspect you have based your change on the Linus tree.

> I used your tree from kernel.org

I found it, I was using master, instead of auto-latest (is it correct?)
But now I see something that I do not understand (apologies if I'm
asking something obvious).

First there is:

[...]
#define ___GFP_WRITE		0x800000u
#define ___GFP_KSWAPD_RECLAIM	0x1000000u
#ifdef CONFIG_LOCKDEP
#define ___GFP_NOLOCKDEP	0x4000000u
#else
#define ___GFP_NOLOCKDEP	0
#endif

Then:

/* Room for N __GFP_FOO bits */
#define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP))



Shouldn't it be either:
___GFP_NOLOCKDEP	0x2000000u

or:

#define __GFP_BITS_SHIFT (25 + 2 * IS_ENABLED(CONFIG_LOCKDEP))


thanks, igor

  parent reply	other threads:[~2017-04-27 12:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-26 13:35 [PATCH 0/1] mm: Improve consistency of ___GFP_xxx masks Igor Stoppa
2017-04-26 13:35 ` [PATCH 1/1] Remove hardcoding of ___GFP_xxx bitmasks Igor Stoppa
2017-04-26 14:47   ` Michal Hocko
2017-04-26 15:29     ` Igor Stoppa
2017-04-27 12:16       ` Question on ___GFP_NOLOCKDEP - Was: " Igor Stoppa
2017-04-27 13:35         ` Michal Hocko
2017-05-10 15:24           ` Vlastimil Babka
2017-04-27 12:18       ` Igor Stoppa [this message]
2017-04-27 13:41       ` Michal Hocko
2017-04-27 14:06         ` Igor Stoppa
2017-04-28  7:40           ` Michal Hocko
2017-04-28  7:43             ` Igor Stoppa
2017-04-28  8:13               ` Igor Stoppa

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