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From: Michael Ellerman <mpe@ellerman•id.au>
To: Anshuman Khandual <khandual@linux•vnet.ibm.com>,
	linuxppc-dev@lists•ozlabs.org
Cc: aneesh.kumar@linux•vnet.ibm.com, christophe.leroy@c-s•fr
Subject: Re: [PATCH V4] powerpc/hugetlb: Add ABI defines for supported HugeTLB page sizes
Date: Fri, 07 Apr 2017 23:01:03 +1000	[thread overview]
Message-ID: <87lgrcgynk.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20170407035539.21688-1-khandual@linux.vnet.ibm.com>

Anshuman Khandual <khandual@linux•vnet.ibm.com> writes:

> This just adds user space exported ABI definitions for 2MB, 16MB, 1GB,
> 16GB non default huge page sizes to be used with mmap() system call.

I updated this for you to include all the sizes.

> diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
> index 03c06ba..ebe99c7 100644
> --- a/arch/powerpc/include/uapi/asm/mman.h
> +++ b/arch/powerpc/include/uapi/asm/mman.h
> @@ -29,4 +29,18 @@
>  #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
>  #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
>  
> +/*
> + * These constant defines should be used for creating the
> + * 'flags' argument (26:31 bit positions) for mmap() system
> + * call should the caller decide to use non default HugeTLB
> + * page size.
> + */

And I reworded the comment the make it clearer (I think) that most users
shouldn't need to use these, and should just use the default size:

/*
 * When MAP_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
 * A value of zero indicates that the default huge page size should be used.
 * To use a non-default huge page size, one of these defines can be used, or the
 * size can be encoded by hand. Note that on most systems only a subset, or
 * possibly none, of these sizes will be available.
 */


Also do you want to send a patch to the man page?

https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man2/mmap.2#n248

cheers

  reply	other threads:[~2017-04-07 13:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-04  6:03 [PATCH] powerpc/hugetlb: Add ABI defines for MAP_HUGE_16MB and MAP_HUGE_16GB Anshuman Khandual
2017-04-04  8:33 ` Aneesh Kumar K.V
2017-04-04 13:50   ` Anshuman Khandual
2017-04-05  5:19     ` [PATCH V2] powerpc/hugetlb: Add ABI defines for supported HugeTLB page sizes Anshuman Khandual
2017-04-05  6:59       ` Balbir Singh
2017-04-05  7:09         ` Michael Ellerman
2017-04-05 11:20           ` [PATCH V3] " Anshuman Khandual
2017-04-06 19:03             ` LEROY Christophe
2017-04-07  3:47               ` Anshuman Khandual
2017-04-07  3:55                 ` [PATCH V4] " Anshuman Khandual
2017-04-07 13:01                   ` Michael Ellerman [this message]
2017-04-07 14:58                     ` Anshuman Khandual
2017-04-07 15:44                     ` Paul Clarke
2017-04-08  9:19                       ` Michael Ellerman
2017-04-10 22:49                   ` [V4] " Michael Ellerman

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