From: Konstantin Khlebnikov <khlebnikov@openvz.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Ben Herrenschmidt <benh@kernel.crashing.org>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>
Subject: Re: [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit
Date: Wed, 21 Mar 2012 17:16:06 +0400 [thread overview]
Message-ID: <4F69D496.2040509@openvz.org> (raw)
In-Reply-To: <20120321100602.GA5522@barrios>
Minchan Kim wrote:
> Hi Konstantin,
>
> It seems to be nice clean up to me and you are a volunteer we have been wanted
> for a long time. Thanks!
> I am one of people who really want to expand vm_flags to 64 bit but when KOSAKI
> tried it, Linus said his concerning, I guess you already saw that.
>
> He want to tidy vm_flags's usage up rather than expanding it.
> Without the discussion about that, just expanding vm_flags would make us use
> it up easily so that we might need more space.
Strictly speaking, my pachset does not expands vm_flags, it just prepares to this.
Anyway vm_flags_t looks better than hard-coded "unsigned long" and messy type-casts around it.
>
> Readahead flags are good candidate to move into another space and arch-specific flags, I guess.
> Another candidate I think of is THP flag. It's just for only anonymous vma now
> (But I am not sure we have a plan to support it for file-backed pages in future)
> so we can move it to anon_vma or somewhere.
> I think other guys might find more somethings
>
> The point is that at least, we have to discuss about clean up current vm_flags's
> use cases before expanding it unconditionally.
Seems like we can easily remove VM_EXECUTABLE
(count in mm->num_exe_file_vmas amount of vmas with vma->vm_file == mm->exe_file
instead of vmas with VM_EXECUTABLE bit)
And probably VM_CAN_NONLINEAR...
>
> On Wed, Mar 21, 2012 at 10:56:07AM +0400, Konstantin Khlebnikov wrote:
>> There is good old tradition: every year somebody submit patches for extending
>> vma->vm_flags upto 64-bits, because there no free bits left on 32-bit systems.
>>
>> previous attempts:
>> https://lkml.org/lkml/2011/4/12/24 (KOSAKI Motohiro)
>> https://lkml.org/lkml/2010/4/27/23 (Benjamin Herrenschmidt)
>> https://lkml.org/lkml/2009/10/1/202 (Hugh Dickins)
>>
>> Here already exist special type for this: vm_flags_t, but not all code uses it.
>> So, before switching vm_flags_t from unsinged long to u64 we must spread
>> vm_flags_t everywhere and fix all possible type-casting problems.
>>
>> There is no functional changes in this patch set,
>> it only prepares code for vma->vm_flags converting.
>>
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next prev parent reply other threads:[~2012-03-21 13:16 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-21 6:56 [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 01/16] mm: introduce NR_VMA_FLAGS Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 02/16] mm: use vm_flags_t for vma flags Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 03/16] mm/shmem: " Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 04/16] mm/nommu: " Konstantin Khlebnikov
2012-03-21 7:08 ` Greg Ungerer
2012-03-21 7:20 ` Konstantin Khlebnikov
2012-03-21 12:01 ` [PATCH v2 " Konstantin Khlebnikov
2012-03-23 6:47 ` Greg Ungerer
2012-03-21 6:56 ` [PATCH 05/16] mm/drivers: " Konstantin Khlebnikov
2012-03-21 10:34 ` Laurent Pinchart
2012-03-21 14:46 ` Greg Kroah-Hartman
2012-03-21 6:56 ` [PATCH 06/16] mm/x86: " Konstantin Khlebnikov
2012-03-21 6:57 ` H. Peter Anvin
2012-03-21 6:56 ` [PATCH 07/16] mm/arm: " Konstantin Khlebnikov
2012-03-22 21:21 ` Andrew Morton
2012-03-21 6:56 ` [PATCH 08/16] mm/unicore32: " Konstantin Khlebnikov
2012-03-27 3:38 ` Guan Xuetao
2012-03-27 5:58 ` Konstantin Khlebnikov
2012-03-27 7:50 ` Guan Xuetao
2012-03-21 6:56 ` [PATCH 09/16] mm/ia64: " Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 10/16] mm/powerpc: " Konstantin Khlebnikov
2012-03-21 6:56 ` [PATCH 11/16] mm/s390: " Konstantin Khlebnikov
2012-03-21 6:57 ` [PATCH 12/16] mm/mips: " Konstantin Khlebnikov
2012-03-21 6:57 ` [PATCH 13/16] mm/parisc: " Konstantin Khlebnikov
2012-03-21 6:57 ` [PATCH 14/16] mm/score: " Konstantin Khlebnikov
2012-03-21 6:57 ` [PATCH 15/16] mm: cast vm_flags_t to u64 before printing Konstantin Khlebnikov
2012-03-21 6:57 ` [PATCH 16/16] mm: vm_flags_t strict type checking Konstantin Khlebnikov
2012-03-21 12:11 ` [PATCH v2 " Konstantin Khlebnikov
2012-03-21 10:06 ` [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit Minchan Kim
2012-03-21 13:16 ` Konstantin Khlebnikov [this message]
2012-03-22 5:39 ` Minchan Kim
2012-03-22 6:22 ` Benjamin Herrenschmidt
2012-03-24 14:46 ` Konstantin Khlebnikov
2012-03-24 15:00 ` Konstantin Khlebnikov
2012-03-24 23:50 ` Benjamin Herrenschmidt
2012-03-25 7:55 ` Konstantin Khlebnikov
2012-03-22 21:26 ` Andrew Morton
2012-03-22 21:28 ` Al Viro
2012-03-22 21:41 ` Andrew Morton
2012-03-22 21:57 ` Al Viro
2012-03-22 22:05 ` Konstantin Khlebnikov
2012-03-22 22:24 ` Konstantin Khlebnikov
2012-03-22 22:39 ` Linus Torvalds
2012-03-22 22:52 ` Konstantin Khlebnikov
2012-03-22 23:09 ` Andrew Morton
2012-03-23 1:42 ` Al Viro
2012-03-22 22:08 ` Linus Torvalds
2012-03-23 16:19 ` KOSAKI Motohiro
2012-03-30 2:19 ` Al Viro
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