From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>,
Boaz Harrosh <boazh@netapp.com>,
linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org,
Andy Lutomirski <luto@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 10/13] mm: Wire up MAP_SYNC
Date: Mon, 21 Aug 2017 15:57:03 -0600 [thread overview]
Message-ID: <20170821215703.GA24473@linux.intel.com> (raw)
In-Reply-To: <20170817160815.30466-11-jack@suse.cz>
On Thu, Aug 17, 2017 at 06:08:12PM +0200, Jan Kara wrote:
> Pretty crude for now...
>
> Signed-off-by: Jan Kara <jack@suse.cz>
One other thing that should probably be wired up before this is all said and
done is the VmFlag string in /proc/<pid>/smaps. Right now when we set this
flag it ends up as ??:
7f44e6cbd000-7f44e6dbd000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms ?? mm hg
The quick one-liner at the end of this patch changes that to:
7fe30e87f000-7fe30e97f000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms sf mm hg
I think that of software can rely on this flag for userspace flushing without
worrying about any new TOCTOU races because there isn't a way to unset the
VM_SYNC flag once it is set - it should be valid as long as the mmap() remains
open and the mmap'd address is valid.
--- 8< ---
fs/proc/task_mmu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index b836fd6..a2a82ed 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -650,6 +650,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_ACCOUNT)] = "ac",
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
+ [ilog2(VM_SYNC)] = "sf",
[ilog2(VM_ARCH_1)] = "ar",
[ilog2(VM_DONTDUMP)] = "dd",
#ifdef CONFIG_MEM_SOFT_DIRTY
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org,
Andy Lutomirski <luto@kernel.org>,
linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Boaz Harrosh <boazh@netapp.com>
Subject: Re: [PATCH 10/13] mm: Wire up MAP_SYNC
Date: Mon, 21 Aug 2017 15:57:03 -0600 [thread overview]
Message-ID: <20170821215703.GA24473@linux.intel.com> (raw)
In-Reply-To: <20170817160815.30466-11-jack@suse.cz>
On Thu, Aug 17, 2017 at 06:08:12PM +0200, Jan Kara wrote:
> Pretty crude for now...
>
> Signed-off-by: Jan Kara <jack@suse.cz>
One other thing that should probably be wired up before this is all said and
done is the VmFlag string in /proc/<pid>/smaps. Right now when we set this
flag it ends up as ??:
7f44e6cbd000-7f44e6dbd000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms ?? mm hg
The quick one-liner at the end of this patch changes that to:
7fe30e87f000-7fe30e97f000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms sf mm hg
I think that of software can rely on this flag for userspace flushing without
worrying about any new TOCTOU races because there isn't a way to unset the
VM_SYNC flag once it is set - it should be valid as long as the mmap() remains
open and the mmap'd address is valid.
--- 8< ---
fs/proc/task_mmu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index b836fd6..a2a82ed 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -650,6 +650,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_ACCOUNT)] = "ac",
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
+ [ilog2(VM_SYNC)] = "sf",
[ilog2(VM_ARCH_1)] = "ar",
[ilog2(VM_DONTDUMP)] = "dd",
#ifdef CONFIG_MEM_SOFT_DIRTY
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>
Cc: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Boaz Harrosh <boazh-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org,
linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 10/13] mm: Wire up MAP_SYNC
Date: Mon, 21 Aug 2017 15:57:03 -0600 [thread overview]
Message-ID: <20170821215703.GA24473@linux.intel.com> (raw)
In-Reply-To: <20170817160815.30466-11-jack-AlSwsSmVLrQ@public.gmane.org>
On Thu, Aug 17, 2017 at 06:08:12PM +0200, Jan Kara wrote:
> Pretty crude for now...
>
> Signed-off-by: Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>
One other thing that should probably be wired up before this is all said and
done is the VmFlag string in /proc/<pid>/smaps. Right now when we set this
flag it ends up as ??:
7f44e6cbd000-7f44e6dbd000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms ?? mm hg
The quick one-liner at the end of this patch changes that to:
7fe30e87f000-7fe30e97f000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1024 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
VmFlags: rd wr sh mr mw me ms sf mm hg
I think that of software can rely on this flag for userspace flushing without
worrying about any new TOCTOU races because there isn't a way to unset the
VM_SYNC flag once it is set - it should be valid as long as the mmap() remains
open and the mmap'd address is valid.
--- 8< ---
fs/proc/task_mmu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index b836fd6..a2a82ed 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -650,6 +650,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_ACCOUNT)] = "ac",
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
+ [ilog2(VM_SYNC)] = "sf",
[ilog2(VM_ARCH_1)] = "ar",
[ilog2(VM_DONTDUMP)] = "dd",
#ifdef CONFIG_MEM_SOFT_DIRTY
next prev parent reply other threads:[~2017-08-21 21:54 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 16:08 [RFC PATCH 0/13 v2] dax, ext4: Synchronous page faults Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` [PATCH 01/13] mm: Remove VM_FAULT_HWPOISON_LARGE_MASK Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` [PATCH 02/13] dax: Simplify arguments of dax_insert_mapping() Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` [PATCH 03/13] dax: Factor out getting of pfn out of iomap Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:06 ` Ross Zwisler
2017-08-18 22:06 ` Ross Zwisler
2017-08-23 18:30 ` Christoph Hellwig
2017-08-23 18:30 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 04/13] dax: Create local variable for VMA in dax_iomap_pte_fault() Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:08 ` Ross Zwisler
2017-08-18 22:08 ` Ross Zwisler
2017-08-23 18:30 ` Christoph Hellwig
2017-08-23 18:30 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 05/13] dax: Create local variable for vmf->flags & FAULT_FLAG_WRITE test Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:08 ` Ross Zwisler
2017-08-18 22:08 ` Ross Zwisler
2017-08-18 22:08 ` Ross Zwisler
2017-08-23 18:31 ` Christoph Hellwig
2017-08-23 18:31 ` Christoph Hellwig
2017-08-23 18:31 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 06/13] dax: Inline dax_insert_mapping() into the callsite Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:10 ` Ross Zwisler
2017-08-18 22:10 ` Ross Zwisler
2017-08-18 22:10 ` Ross Zwisler
2017-08-23 18:31 ` Christoph Hellwig
2017-08-23 18:31 ` Christoph Hellwig
2017-08-23 18:31 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 07/13] dax: Inline dax_pmd_insert_mapping() " Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:12 ` Ross Zwisler
2017-08-18 22:12 ` Ross Zwisler
2017-08-18 22:12 ` Ross Zwisler
2017-08-23 18:32 ` Christoph Hellwig
2017-08-23 18:32 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 08/13] dax: Fix comment describing dax_iomap_fault() Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-18 22:12 ` Ross Zwisler
2017-08-18 22:12 ` Ross Zwisler
2017-08-23 18:32 ` Christoph Hellwig
2017-08-23 18:32 ` Christoph Hellwig
2017-08-17 16:08 ` [PATCH 09/13] dax: Allow dax_iomap_fault() to return pfn Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-21 18:45 ` Ross Zwisler
2017-08-21 18:45 ` Ross Zwisler
2017-08-23 18:34 ` Christoph Hellwig
2017-08-23 18:34 ` Christoph Hellwig
2017-08-23 18:34 ` Christoph Hellwig
2017-08-24 7:26 ` Jan Kara
2017-08-24 7:26 ` Jan Kara
2017-08-17 16:08 ` [PATCH 10/13] mm: Wire up MAP_SYNC Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-21 21:37 ` Ross Zwisler
2017-08-21 21:37 ` Ross Zwisler
2017-08-22 9:36 ` Jan Kara
2017-08-22 9:36 ` Jan Kara
2017-08-21 21:57 ` Ross Zwisler [this message]
2017-08-21 21:57 ` Ross Zwisler
2017-08-21 21:57 ` Ross Zwisler
2017-08-22 9:34 ` Jan Kara
2017-08-22 9:34 ` Jan Kara
2017-08-22 17:27 ` Dan Williams
2017-08-22 17:27 ` Dan Williams
2017-08-22 17:27 ` Dan Williams
2017-08-23 18:43 ` Christoph Hellwig
2017-08-23 18:43 ` Christoph Hellwig
2017-08-23 18:43 ` Christoph Hellwig
2017-08-24 7:16 ` Jan Kara
2017-08-24 7:16 ` Jan Kara
2017-08-17 16:08 ` [PATCH 11/13] dax, iomap: Add support for synchronous faults Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-21 18:58 ` Ross Zwisler
2017-08-21 18:58 ` Ross Zwisler
2017-08-22 9:46 ` Jan Kara
2017-08-22 9:46 ` Jan Kara
2017-08-21 21:09 ` Ross Zwisler
2017-08-21 21:09 ` Ross Zwisler
2017-08-22 10:08 ` Jan Kara
2017-08-22 10:08 ` Jan Kara
2017-08-22 10:08 ` Jan Kara
2017-08-24 12:27 ` Christoph Hellwig
2017-08-24 12:27 ` Christoph Hellwig
2017-08-24 12:34 ` Jan Kara
2017-08-24 12:34 ` Jan Kara
2017-08-24 13:38 ` Christoph Hellwig
2017-08-24 13:38 ` Christoph Hellwig
2017-08-24 16:45 ` Jan Kara
2017-08-24 16:45 ` Jan Kara
2017-08-17 16:08 ` [PATCH 12/13] dax: Implement dax_insert_pfn_mkwrite() Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-21 19:01 ` Ross Zwisler
2017-08-21 19:01 ` Ross Zwisler
2017-08-17 16:08 ` [PATCH 13/13] ext4: Support for synchronous DAX faults Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-17 16:08 ` Jan Kara
2017-08-21 19:19 ` Ross Zwisler
2017-08-21 19:19 ` Ross Zwisler
2017-08-22 10:18 ` Jan Kara
2017-08-22 10:18 ` Jan Kara
2017-08-22 10:18 ` Jan Kara
2017-08-23 18:37 ` Christoph Hellwig
2017-08-23 18:37 ` Christoph Hellwig
2017-08-24 7:18 ` Jan Kara
2017-08-24 7:18 ` Jan Kara
2017-08-24 12:31 ` Christoph Hellwig
2017-08-24 12:31 ` Christoph Hellwig
2017-08-24 12:34 ` Christoph Hellwig
2017-08-24 12:34 ` Christoph Hellwig
2017-08-24 12:34 ` Christoph Hellwig
2017-08-24 12:36 ` Jan Kara
2017-08-24 12:36 ` Jan Kara
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