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From: Davidlohr Bueso <dave@stgolabs.net>
To: Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, manfred@colorfullife.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly
Date: Fri, 10 Feb 2017 08:51:11 -0800	[thread overview]
Message-ID: <20170210165111.GB2392@linux-80c1.suse> (raw)
In-Reply-To: <20170210102044.GA10054@dhcp22.suse.cz>

On Fri, 10 Feb 2017, Michal Hocko wrote:

>On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote:
>> The SHM_HUGE_* stuff  was introduced in:
>>
>>    42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB)
>>
>> It unnecessarily adds another layer, specific to sysv shm, without
>> anything special about it: the macros are identical to the MAP_HUGE_*
>> stuff, which in turn does correctly describe the hugepage subsystem.
>>
>> One example of the problems with extra layers what this patch fixes:
>> mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously
>> harmless but it would still be grand to get rid of it -- although
>> now in the manpages I don't see that happening.
>
>Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi
>headers AFAICS.

Yeah that was my original idea, however I noticed that shmget.2 mentions
kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So
dropping _MASK doesn't make sense if we are going to keep _SHIFT.

Thanks,
Davidlohr

WARNING: multiple messages have this Message-ID (diff)
From: Davidlohr Bueso <dave@stgolabs.net>
To: Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, manfred@colorfullife.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly
Date: Fri, 10 Feb 2017 08:51:11 -0800	[thread overview]
Message-ID: <20170210165111.GB2392@linux-80c1.suse> (raw)
In-Reply-To: <20170210102044.GA10054@dhcp22.suse.cz>

On Fri, 10 Feb 2017, Michal Hocko wrote:

>On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote:
>> The SHM_HUGE_* stuff  was introduced in:
>>
>>    42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB)
>>
>> It unnecessarily adds another layer, specific to sysv shm, without
>> anything special about it: the macros are identical to the MAP_HUGE_*
>> stuff, which in turn does correctly describe the hugepage subsystem.
>>
>> One example of the problems with extra layers what this patch fixes:
>> mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously
>> harmless but it would still be grand to get rid of it -- although
>> now in the manpages I don't see that happening.
>
>Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi
>headers AFAICS.

Yeah that was my original idea, however I noticed that shmget.2 mentions
kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So
dropping _MASK doesn't make sense if we are going to keep _SHIFT.

Thanks,
Davidlohr

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  reply	other threads:[~2017-02-10 16:51 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-09 20:52 [PATCH -tip 0/4] ipc/shm: moar updates for v4.11 Davidlohr Bueso
2017-02-09 20:52 ` [PATCH 1/4] ipc/shm: do not check for MAP_POPULATE Davidlohr Bueso
2017-02-10  2:15   ` Hugh Dickins
2017-02-13 18:14     ` Davidlohr Bueso
2017-02-09 20:53 ` [PATCH 2/4] ipc/shm: some shmat cleanups Davidlohr Bueso
2017-02-09 20:53 ` [PATCH 3/4] sysv,ipc: cacheline align kern_ipc_perm Davidlohr Bueso
2017-02-09 20:53 ` [PATCH 4/4] mm,hugetlb: compute page_size_log properly Davidlohr Bueso
2017-02-09 20:53   ` Davidlohr Bueso
2017-02-10 10:20   ` Michal Hocko
2017-02-10 10:20     ` Michal Hocko
2017-02-10 16:51     ` Davidlohr Bueso [this message]
2017-02-10 16:51       ` Davidlohr Bueso
2017-02-20 16:11       ` Michal Hocko
2017-02-20 16:11         ` Michal Hocko
2017-02-22 16:03         ` Davidlohr Bueso
2017-02-22 16:03           ` Davidlohr Bueso
2017-02-22 16:11           ` Michal Hocko
2017-02-22 16:11             ` Michal Hocko

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