From: Jeff Moyer <jmoyer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>,
linux-nvdimm@lists.01.org, Christoph Hellwig <hch@lst.de>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
akpm@linux-foundation.org
Subject: Re: [PATCH 2/3] dax: stop using VM_MIXEDMAP for dax
Date: Thu, 28 Sep 2017 12:32:44 -0400 [thread overview]
Message-ID: <x49poaaaimr.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <150655619012.700.15161500295945223238.stgit@dwillia2-desk3.amr.corp.intel.com> (Dan Williams's message of "Wed, 27 Sep 2017 16:49:50 -0700")
Dan Williams <dan.j.williams@intel.com> writes:
> Now that we always have pages for DAX we can stop setting VM_MIXEDMAP.
> This does require some small fixups for the pte insert routines that dax
> utilizes.
It used to be that userspace would look to see if it had a 'mm' entry in
/proc/pid/smaps to determine whether or not it got a direct mapping.
Later, that same userspace (nvml) just uniformly declared dax not
available from any Linux file system, since msync was required. And, I
guess DAX has always been marked experimental, so the interface can be
changed.
All this is to say I guess it's fine to change this.
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 680506faceae..d682f60670ff 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1111,7 +1111,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
> * We later require that vma->vm_flags == vm_flags,
> * so this tests vma->vm_flags & VM_SPECIAL, too.
> */
> - if (vm_flags & VM_SPECIAL)
> + if ((vm_flags & VM_SPECIAL))
> return NULL;
That looks superfluous.
-Jeff
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WARNING: multiple messages have this Message-ID (diff)
From: Jeff Moyer <jmoyer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: akpm@linux-foundation.org, Jan Kara <jack@suse.cz>,
linux-nvdimm@lists.01.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 2/3] dax: stop using VM_MIXEDMAP for dax
Date: Thu, 28 Sep 2017 12:32:44 -0400 [thread overview]
Message-ID: <x49poaaaimr.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <150655619012.700.15161500295945223238.stgit@dwillia2-desk3.amr.corp.intel.com> (Dan Williams's message of "Wed, 27 Sep 2017 16:49:50 -0700")
Dan Williams <dan.j.williams@intel.com> writes:
> Now that we always have pages for DAX we can stop setting VM_MIXEDMAP.
> This does require some small fixups for the pte insert routines that dax
> utilizes.
It used to be that userspace would look to see if it had a 'mm' entry in
/proc/pid/smaps to determine whether or not it got a direct mapping.
Later, that same userspace (nvml) just uniformly declared dax not
available from any Linux file system, since msync was required. And, I
guess DAX has always been marked experimental, so the interface can be
changed.
All this is to say I guess it's fine to change this.
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 680506faceae..d682f60670ff 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1111,7 +1111,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
> * We later require that vma->vm_flags == vm_flags,
> * so this tests vma->vm_flags & VM_SPECIAL, too.
> */
> - if (vm_flags & VM_SPECIAL)
> + if ((vm_flags & VM_SPECIAL))
> return NULL;
That looks superfluous.
-Jeff
--
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WARNING: multiple messages have this Message-ID (diff)
From: Jeff Moyer <jmoyer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: akpm@linux-foundation.org, Jan Kara <jack@suse.cz>,
linux-nvdimm@lists.01.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 2/3] dax: stop using VM_MIXEDMAP for dax
Date: Thu, 28 Sep 2017 12:32:44 -0400 [thread overview]
Message-ID: <x49poaaaimr.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <150655619012.700.15161500295945223238.stgit@dwillia2-desk3.amr.corp.intel.com> (Dan Williams's message of "Wed, 27 Sep 2017 16:49:50 -0700")
Dan Williams <dan.j.williams@intel.com> writes:
> Now that we always have pages for DAX we can stop setting VM_MIXEDMAP.
> This does require some small fixups for the pte insert routines that dax
> utilizes.
It used to be that userspace would look to see if it had a 'mm' entry in
/proc/pid/smaps to determine whether or not it got a direct mapping.
Later, that same userspace (nvml) just uniformly declared dax not
available from any Linux file system, since msync was required. And, I
guess DAX has always been marked experimental, so the interface can be
changed.
All this is to say I guess it's fine to change this.
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 680506faceae..d682f60670ff 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1111,7 +1111,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
> * We later require that vma->vm_flags == vm_flags,
> * so this tests vma->vm_flags & VM_SPECIAL, too.
> */
> - if (vm_flags & VM_SPECIAL)
> + if ((vm_flags & VM_SPECIAL))
> return NULL;
That looks superfluous.
-Jeff
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-09-28 16:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-27 23:49 [PATCH 0/3] dax: require 'struct page' and other fixups Dan Williams
2017-09-27 23:49 ` Dan Williams
2017-09-27 23:49 ` [PATCH 1/3] dax: disable filesystem dax on devices that do not map pages Dan Williams
2017-09-27 23:49 ` Dan Williams
2017-09-28 16:25 ` Jeff Moyer
2017-09-28 16:25 ` Jeff Moyer
2017-09-28 16:25 ` Jeff Moyer
2017-09-28 16:28 ` Dan Williams
2017-09-28 16:28 ` Dan Williams
2017-09-27 23:49 ` [PATCH 2/3] dax: stop using VM_MIXEDMAP for dax Dan Williams
2017-09-27 23:49 ` Dan Williams
2017-09-28 0:09 ` Dan Williams
2017-09-28 0:09 ` Dan Williams
2017-09-28 16:32 ` Jeff Moyer [this message]
2017-09-28 16:32 ` Jeff Moyer
2017-09-28 16:32 ` Jeff Moyer
2017-09-28 16:41 ` Dan Williams
2017-09-27 23:49 ` [PATCH 3/3] dax: stop using VM_HUGEPAGE " Dan Williams
2017-09-27 23:49 ` Dan Williams
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