On Mon, Jun 15, 2015 at 08:19:07AM -1000, Linus Torvalds wrote:
What if the process doing the polling never doors anything with the end
result? Maybe it meant to, but it got killed before it could? Are you going
to leave everybody else blocked, even though there are pending events?
Yes, it
ithout
> #include
>
> Introduced by commit 2873f48b446c ("userfaultfd: uAPI").
Here's the fix:
===
>From 02b31b0a5e9dd5ddbcb4ad86f63fbcb0a2b5d8f2 Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli
Date: Thu, 4 Jun 2015 14:54:40 +0200
Subject: [PATCH] userfaultfd: uAPI: add
/types.h
Introduced by commit 2873f48b446c (userfaultfd: uAPI).
Here's the fix:
===
From 02b31b0a5e9dd5ddbcb4ad86f63fbcb0a2b5d8f2 Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli aarca...@redhat.com
Date: Thu, 4 Jun 2015 14:54:40 +0200
Subject: [PATCH] userfaultfd: uAPI: add missing include/types.h
On Tue, May 26, 2015 at 04:35:47PM +0200, Christoffer Dall wrote:
> Any chance you could send me the memhog tool?
memhog is just the first that come to mind because I got it
preinstalled everywhere (I only miss it on cyanogenmod as there's no
numactl there... yet).
Anything else would do as
On Tue, May 26, 2015 at 10:08:48AM +0200, Christoffer Dall wrote:
> > echo 0 > /sys/kernel/mm/transparent_hugepage/khugepaged/pages_to_scan
>
> this returns -EINVAL.
>
Oops sorry, I haven't re-read the code, pages_to_scan 0 does not make
sense, it would only be useful for debugging purposes
On Tue, May 26, 2015 at 04:35:47PM +0200, Christoffer Dall wrote:
Any chance you could send me the memhog tool?
memhog is just the first that come to mind because I got it
preinstalled everywhere (I only miss it on cyanogenmod as there's no
numactl there... yet).
Anything else would do as well,
On Tue, May 26, 2015 at 10:08:48AM +0200, Christoffer Dall wrote:
echo 0 /sys/kernel/mm/transparent_hugepage/khugepaged/pages_to_scan
this returns -EINVAL.
Oops sorry, I haven't re-read the code, pages_to_scan 0 does not make
sense, it would only be useful for debugging purposes because
Hello Christoffer,
On Sun, May 24, 2015 at 09:34:04PM +0200, Christoffer Dall wrote:
> Hi all,
>
> I noticed a regression on my arm64 APM X-Gene system a couple
> of weeks back. I would occassionally see the system lock up and see RCU
> stalls during the caching phase of kernbench. I then
Hello,
On Mon, May 25, 2015 at 09:18:01PM +1000, Stephen Rothwell wrote:
> Hi Andrew,
>
> After merging the akpm-current tree, today's linux-next build (powerpc
> ppc64_defconfig) failed like this:
>
> __NR_syscalls (364) is not one more than the last syscall (364)
>
> Caused by commit
Hello,
On Mon, May 25, 2015 at 09:18:01PM +1000, Stephen Rothwell wrote:
Hi Andrew,
After merging the akpm-current tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:
__NR_syscalls (364) is not one more than the last syscall (364)
Caused by commit d7766613717b
Hello Christoffer,
On Sun, May 24, 2015 at 09:34:04PM +0200, Christoffer Dall wrote:
Hi all,
I noticed a regression on my arm64 APM X-Gene system a couple
of weeks back. I would occassionally see the system lock up and see RCU
stalls during the caching phase of kernbench. I then wrote a
ms like this.
===
>From 2f0a48670dc515932dec8b983871ec35caeba553 Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli
Date: Sat, 23 May 2015 02:26:32 +0200
Subject: [PATCH] userfaultfd: update the uffd_msg structure to be the same on
32/64bit
Avoiding to using packed allowed the code to be nicer and it avoided
the rese
On Fri, May 22, 2015 at 01:18:22PM -0700, Andrew Morton wrote:
> On Thu, 14 May 2015 19:31:19 +0200 Andrea Arcangeli
> wrote:
>
> > If the rwsem starves writers it wasn't strictly a bug but lockdep
> > doesn't like it and this avoids depending on lowlevel implementation
&g
On Fri, May 22, 2015 at 01:18:22PM -0700, Andrew Morton wrote:
On Thu, 14 May 2015 19:31:19 +0200 Andrea Arcangeli aarca...@redhat.com
wrote:
If the rwsem starves writers it wasn't strictly a bug but lockdep
doesn't like it and this avoids depending on lowlevel implementation
details
2f0a48670dc515932dec8b983871ec35caeba553 Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli aarca...@redhat.com
Date: Sat, 23 May 2015 02:26:32 +0200
Subject: [PATCH] userfaultfd: update the uffd_msg structure to be the same on
32/64bit
Avoiding to using packed allowed the code to be nicer and it avoided
the reserved1/2/3
Hi Kirill,
On Thu, May 21, 2015 at 04:11:11PM +0300, Kirill Smelkov wrote:
> Sorry for maybe speaking up too late, but here is additional real
Not too late, in fact I don't think there's any change required for
this at this stage, but it'd be great if you could help me to review.
> Since arrays
Hi Kirill,
On Thu, May 21, 2015 at 04:11:11PM +0300, Kirill Smelkov wrote:
Sorry for maybe speaking up too late, but here is additional real
Not too late, in fact I don't think there's any change required for
this at this stage, but it'd be great if you could help me to review.
Since arrays
Hello Richard,
On Tue, May 19, 2015 at 11:59:42PM +0200, Richard Weinberger wrote:
> On Tue, May 19, 2015 at 11:38 PM, Andrew Morton
> wrote:
> > On Thu, 14 May 2015 19:30:57 +0200 Andrea Arcangeli
> > wrote:
> >
> >> This is the latest userfaultfd patchset ag
Hi Andrew,
On Tue, May 19, 2015 at 02:38:01PM -0700, Andrew Morton wrote:
> On Thu, 14 May 2015 19:30:57 +0200 Andrea Arcangeli
> wrote:
>
> > This is the latest userfaultfd patchset against mm-v4.1-rc3
> > 2015-05-14-10:04.
>
> It would be useful to have some userf
Hi Andrew,
On Tue, May 19, 2015 at 02:38:01PM -0700, Andrew Morton wrote:
On Thu, 14 May 2015 19:30:57 +0200 Andrea Arcangeli aarca...@redhat.com
wrote:
This is the latest userfaultfd patchset against mm-v4.1-rc3
2015-05-14-10:04.
It would be useful to have some userfaultfd testcases
Hello Richard,
On Tue, May 19, 2015 at 11:59:42PM +0200, Richard Weinberger wrote:
On Tue, May 19, 2015 at 11:38 PM, Andrew Morton
a...@linux-foundation.org wrote:
On Thu, 14 May 2015 19:30:57 +0200 Andrea Arcangeli aarca...@redhat.com
wrote:
This is the latest userfaultfd patchset
On Thu, May 14, 2015 at 10:49:06AM -0700, Linus Torvalds wrote:
> On Thu, May 14, 2015 at 10:31 AM, Andrea Arcangeli
> wrote:
> > +static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
> > + struct userfaultfd_wake
On Thu, May 14, 2015 at 10:49:06AM -0700, Linus Torvalds wrote:
On Thu, May 14, 2015 at 10:31 AM, Andrea Arcangeli aarca...@redhat.com
wrote:
+static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
+ struct userfaultfd_wake_range
This allows to select the userfaultfd during configuration to build it.
Signed-off-by: Andrea Arcangeli
---
fs/Makefile | 1 +
init/Kconfig | 11 +++
2 files changed, 12 insertions(+)
diff --git a/fs/Makefile b/fs/Makefile
index cb92fd4..53e59b2 100644
--- a/fs/Makefile
+++ b/fs
This implements the uABI of UFFDIO_COPY and UFFDIO_ZEROPAGE.
Signed-off-by: Andrea Arcangeli
---
include/uapi/linux/userfaultfd.h | 42 +++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux
This activates the userfaultfd syscall.
Signed-off-by: Andrea Arcangeli
---
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/uapi/asm/unistd.h | 1 +
arch/x86/syscalls/syscall_32.tbl | 1 +
arch/x86/syscalls/syscall_64.tbl | 1 +
include/linux/syscalls.h
This makes read O(1) and poll that was already O(1) becomes lockless.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 172 +++
1 file changed, 98 insertions(+), 74 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index
erfault
thread
This patch removes the need of both UFFDIO_WAKE and of the associated
per-page tristate as well.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 81 +---
1 file changed, 66 insertions(+), 15 deletions(-)
diff --git a/fs/use
Kernel header defining the methods needed by the VM common code to
interact with the userfaultfd.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 79 +++
1 file changed, 79 insertions(+)
create mode 100644 include/linux
If the rwsem starves writers it wasn't strictly a bug but lockdep
doesn't like it and this avoids depending on lowlevel implementation
details of the lock.
Signed-off-by: Andrea Arcangeli
---
mm/userfaultfd.c | 92
1 file changed, 66
Update comment.
Signed-off-by: Andrea Arcangeli
---
include/uapi/linux/userfaultfd.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index 5e1c2f7..03f21cb 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 4 ++--
include/uapi/linux/userfaultfd.h | 10 --
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 1c9be61..9085365 100644
--- a/fs/userfaultfd.c
+++ b/fs
ow
QEMU/KVM uses userfaultfd to implement postcopy live migration.
http://git.kernel.org/cgit/linux/kernel/git/andrea/aa.git/commit/?h=userfault=016f9523b7b2238851533736e84452cb00b2ddcd
Andrea Arcangeli (22):
userfaultfd: linux/Documentation/vm/userfaultfd.txt
userfaultfd: waitqueue
Signed-off-by: Andrea Arcangeli
---
mm/huge_memory.c | 6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c221be3..9671f51 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2198,7 +2198,8 @@ static int __collapse_huge_page_isol
significant in case of repeated faults on the same address from
multiple threads.
This optimization is justified by the measurement that the number of
spurious UFFDIO_WAKE accounts for 5% and 10% of the total
userfaults for heavy workloads, so it's worth optimizing those away.
Signed-off-
sed as parameter so the "read|write"
kind of fault can be passed to userland.
Signed-off-by: Andrea Arcangeli
---
mm/huge_memory.c | 69 ++--
mm/memory.c | 16 +
2 files changed, 63 insertions(+), 22 deletions(-)
di
of new events that can be extended or of new future
bits for already shipped events, is limited to 64 by the features
field of the uffdio_api structure. If more will be needed a bump of
UFFD_API will be required.
Signed-off-by: Andrea Arcangeli
---
Documentation/vm/userfaultfd.txt | 12 +++---
fs
Add documentation.
Signed-off-by: Andrea Arcangeli
---
Documentation/vm/userfaultfd.txt | 140 +++
1 file changed, 140 insertions(+)
create mode 100644 Documentation/vm/userfaultfd.txt
diff --git a/Documentation/vm/userfaultfd.txt b/Documentation/vm
These two ioctl allows to either atomically copy or to map zeropages
into the virtual address space. This is used by the thread that opened
the userfaultfd to resolve the userfaults.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 96
to know when there are new pending userfaults to be
read (POLLIN).
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 1008 ++
1 file changed, 1008 insertions(+)
create mode 100644 fs/userfaultfd.c
diff --git a/fs/userfaultfd.c b/fs
vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge
must be aware about so that we can merge vmas back like they were
originally before arming the userfaultfd on some memory range.
Signed-off-by: Andrea Arcangeli
---
include/linux/mm.h | 2 +-
mm/madvise.c | 3 ++-
Use proper slab to guarantee alignment.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 39 +++
1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 3d26f41..5542fe7 100644
--- a/fs/userfaultfd.c
These two flags gets set in vma->vm_flags to tell the VM common code
if the userfaultfd is armed and in which mode (only tracking missing
faults, only tracking wrprotect faults or both). If neither flags is
set it means the userfaultfd is not armed on the vma.
Signed-off-by: Andrea Arcang
This implements mcopy_atomic and mfill_zeropage that are the lowlevel
VM methods that are invoked respectively by the UFFDIO_COPY and
UFFDIO_ZEROPAGE userfaultfd commands.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 6 +
mm/Makefile | 1 +
mm
userfaultfd needs to wake all waitqueues (pass 0 as nr parameter),
instead of the current hardcoded 1 (that would wake just the first
waitqueue in the head list).
Signed-off-by: Andrea Arcangeli
---
include/linux/wait.h | 5 +++--
kernel/sched/wait.c | 7 ---
net/sunrpc/sched.c | 2 +-
3
This adds the vm_userfaultfd_ctx to the vm_area_struct.
Signed-off-by: Andrea Arcangeli
---
include/linux/mm_types.h | 11 +++
kernel/fork.c| 1 +
2 files changed, 12 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 0038ac7..2836da7
Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol.
Signed-off-by: Andrea Arcangeli
---
Documentation/ioctl/ioctl-number.txt | 1 +
include/uapi/linux/Kbuild| 1 +
include/uapi/linux/userfaultfd.h | 81
3 files
This adds the vm_userfaultfd_ctx to the vm_area_struct.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/linux/mm_types.h | 11 +++
kernel/fork.c| 1 +
2 files changed, 12 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index
Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
Documentation/ioctl/ioctl-number.txt | 1 +
include/uapi/linux/Kbuild| 1 +
include/uapi/linux/userfaultfd.h | 81
This makes read O(1) and poll that was already O(1) becomes lockless.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 172 +++
1 file changed, 98 insertions(+), 74 deletions(-)
diff --git a/fs/userfaultfd.c b/fs
of both UFFDIO_WAKE and of the associated
per-page tristate as well.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 81 +---
1 file changed, 66 insertions(+), 15 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
of new events that can be extended or of new future
bits for already shipped events, is limited to 64 by the features
field of the uffdio_api structure. If more will be needed a bump of
UFFD_API will be required.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
Documentation/vm/userfaultfd.txt
as parameter so the read|write
kind of fault can be passed to userland.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
mm/huge_memory.c | 69 ++--
mm/memory.c | 16 +
2 files changed, 63 insertions(+), 22 deletions(-)
diff --git
of repeated faults on the same address from
multiple threads.
This optimization is justified by the measurement that the number of
spurious UFFDIO_WAKE accounts for 5% and 10% of the total
userfaults for heavy workloads, so it's worth optimizing those away.
Signed-off-by: Andrea Arcangeli aarca
-by: Andrea Arcangeli aarca...@redhat.com
---
mm/huge_memory.c | 6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c221be3..9671f51 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2198,7 +2198,8 @@ static int
QEMU/KVM uses userfaultfd to implement postcopy live migration.
http://git.kernel.org/cgit/linux/kernel/git/andrea/aa.git/commit/?h=userfaultid=016f9523b7b2238851533736e84452cb00b2ddcd
Andrea Arcangeli (22):
userfaultfd: linux/Documentation/vm/userfaultfd.txt
userfaultfd: waitqueue
Kernel header defining the methods needed by the VM common code to
interact with the userfaultfd.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/linux/userfaultfd_k.h | 79 +++
1 file changed, 79 insertions(+)
create mode 100644 include
If the rwsem starves writers it wasn't strictly a bug but lockdep
doesn't like it and this avoids depending on lowlevel implementation
details of the lock.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
mm/userfaultfd.c | 92
1
Update comment.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/uapi/linux/userfaultfd.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index 5e1c2f7..03f21cb 100644
--- a/include/uapi/linux
-by: Pavel Emelyanov xe...@parallels.com
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 4 ++--
include/uapi/linux/userfaultfd.h | 10 --
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index
This implements the uABI of UFFDIO_COPY and UFFDIO_ZEROPAGE.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/uapi/linux/userfaultfd.h | 42 +++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/userfaultfd.h b
This allows to select the userfaultfd during configuration to build it.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/Makefile | 1 +
init/Kconfig | 11 +++
2 files changed, 12 insertions(+)
diff --git a/fs/Makefile b/fs/Makefile
index cb92fd4..53e59b2 100644
--- a/fs
This activates the userfaultfd syscall.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/uapi/asm/unistd.h | 1 +
arch/x86/syscalls/syscall_32.tbl | 1 +
arch/x86/syscalls/syscall_64.tbl | 1 +
include/linux
userfaultfd needs to wake all waitqueues (pass 0 as nr parameter),
instead of the current hardcoded 1 (that would wake just the first
waitqueue in the head list).
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/linux/wait.h | 5 +++--
kernel/sched/wait.c | 7 ---
net/sunrpc
These two flags gets set in vma-vm_flags to tell the VM common code
if the userfaultfd is armed and in which mode (only tracking missing
faults, only tracking wrprotect faults or both). If neither flags is
set it means the userfaultfd is not armed on the vma.
Signed-off-by: Andrea Arcangeli aarca
This implements mcopy_atomic and mfill_zeropage that are the lowlevel
VM methods that are invoked respectively by the UFFDIO_COPY and
UFFDIO_ZEROPAGE userfaultfd commands.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/linux/userfaultfd_k.h | 6 +
mm/Makefile
Use proper slab to guarantee alignment.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 39 +++
1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 3d26f41..5542fe7 100644
--- a/fs
Add documentation.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
Documentation/vm/userfaultfd.txt | 140 +++
1 file changed, 140 insertions(+)
create mode 100644 Documentation/vm/userfaultfd.txt
diff --git a/Documentation/vm/userfaultfd.txt b
to know when there are new pending userfaults to be
read (POLLIN).
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 1008 ++
1 file changed, 1008 insertions(+)
create mode 100644 fs/userfaultfd.c
diff --git a/fs
vma-vm_userfaultfd_ctx is yet another vma parameter that vma_merge
must be aware about so that we can merge vmas back like they were
originally before arming the userfaultfd on some memory range.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
include/linux/mm.h | 2 +-
mm/madvise.c
These two ioctl allows to either atomically copy or to map zeropages
into the virtual address space. This is used by the thread that opened
the userfaultfd to resolve the userfaults.
Signed-off-by: Andrea Arcangeli aarca...@redhat.com
---
fs/userfaultfd.c | 96
Hello,
On Thu, Apr 23, 2015 at 09:29:07AM +0300, Pavel Emelyanov wrote:
> So your proposal is to always report 16 bytes per PF from read() and
> let userspace decide itself how to handle the result?
Reading 16bytes for each userfault (instead of 8) and sharing the same
read(2) protocol
Hello,
On Thu, Apr 23, 2015 at 09:29:07AM +0300, Pavel Emelyanov wrote:
So your proposal is to always report 16 bytes per PF from read() and
let userspace decide itself how to handle the result?
Reading 16bytes for each userfault (instead of 8) and sharing the same
read(2) protocol (UFFD_API)
On Wed, Mar 18, 2015 at 10:35:17PM +0300, Pavel Emelyanov wrote:
> + if (!(ctx->features & UFFD_FEATURE_LONGMSG)) {
If we are to use different protocols, it'd be nicer to have two
different methods to assign to userfaultfd_fops.read that calls an
__always_inline function, so that the
Hi Pavel,
On Wed, Mar 18, 2015 at 10:34:26PM +0300, Pavel Emelyanov wrote:
> Hi,
>
> On the recent LSF Andrea presented his userfault-fd patches and
> I had shown some issues that appear in usage scenarios when the
> monitor task and mm task do not cooperate to each other on VM
> changes (and
Hi Pavel,
On Wed, Mar 18, 2015 at 10:34:26PM +0300, Pavel Emelyanov wrote:
Hi,
On the recent LSF Andrea presented his userfault-fd patches and
I had shown some issues that appear in usage scenarios when the
monitor task and mm task do not cooperate to each other on VM
changes (and
On Wed, Mar 18, 2015 at 10:35:17PM +0300, Pavel Emelyanov wrote:
+ if (!(ctx-features UFFD_FEATURE_LONGMSG)) {
If we are to use different protocols, it'd be nicer to have two
different methods to assign to userfaultfd_fops.read that calls an
__always_inline function, so that the
This implements the uABI of UFFDIO_REMAP.
Notably one mode bitflag is also forwarded (and in turn known) by the
lowlevel remap_pages method.
Signed-off-by: Andrea Arcangeli
---
include/uapi/linux/userfaultfd.h | 27 ++-
1 file changed, 26 insertions(+), 1 deletion
Signed-off-by: Andrea Arcangeli
---
mm/huge_memory.c | 6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5374132..8f1b6a5 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2145,7 +2145,8 @@ static int __collapse_huge_page_isol
On Thu, Mar 05, 2015 at 09:39:48AM -0800, Linus Torvalds wrote:
> Is this really worth it? On real loads? That people are expected to use?
I fully agree that it's not worth merging upstream UFFDIO_REMAP until
(and if) a real world usage for it will showup. To further clarify:
would this not have
This adds the vm_userfaultfd_ctx to the vm_area_struct.
Signed-off-by: Andrea Arcangeli
---
include/linux/mm_types.h | 11 +++
kernel/fork.c| 1 +
2 files changed, 12 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 199a03a..fbf21f5
Defines the uAPI of the userfaultfd, notably the ioctl numbers and protocol.
Signed-off-by: Andrea Arcangeli
---
Documentation/ioctl/ioctl-number.txt | 1 +
include/uapi/linux/userfaultfd.h | 81
2 files changed, 82 insertions(+)
create mode 100644
This allows to select the userfaultfd during configuration to build it.
Signed-off-by: Andrea Arcangeli
---
fs/Makefile | 1 +
init/Kconfig | 11 +++
2 files changed, 12 insertions(+)
diff --git a/fs/Makefile b/fs/Makefile
index a88ac48..ba8ab62 100644
--- a/fs/Makefile
+++ b/fs
in some anon_vma.
Signed-off-by: Andrea Arcangeli
---
include/linux/swap.h | 6 ++
mm/swapfile.c| 13 +
2 files changed, 19 insertions(+)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4759491..9adda11 100644
--- a/include/linux/swap.h
+++ b/include/linux
specially if copying only a few pages at time, copying without
TLB flush is faster.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 51 +++
1 file changed, 51 insertions(+)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 6230f22..b4c
These helpers will be used to know if to call handle_userfault() during
wrprotect faults in order to deliver the wrprotect faults to userland.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 10 ++
1 file changed, 10 insertions(+)
diff --git a/include/linux
e remap_pages runs.
Signed-off-by: Andrea Arcangeli
---
mm/huge_memory.c | 23 +++
mm/rmap.c| 9 +
2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8f1b6a5..1e25cb3 100644
--- a/mm/huge_memory.c
+++
These two flags gets set in vma->vm_flags to tell the VM common code
if the userfaultfd is armed and in which mode (only tracking missing
faults, only tracking wrprotect faults or both). If neither flags is
set it means the userfaultfd is not armed on the vma.
Signed-off-by: Andrea Arcang
Add documentation.
Signed-off-by: Andrea Arcangeli
---
Documentation/vm/userfaultfd.txt | 97
1 file changed, 97 insertions(+)
create mode 100644 Documentation/vm/userfaultfd.txt
diff --git a/Documentation/vm/userfaultfd.txt b/Documentation/vm
strictly required by the wrprotect
tracking mode, so it's no problem to solve this later. Because of its
inherent racy nature, nobody could possibly depend on a racy SIGBUS
being raised now, when it won't be raised anymore later.
Andrea Arcangeli (21):
userfaultfd: waitqueue: add nr wake parameter
vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge
must be aware about so that we can merge vmas back like they were
originally before arming the userfaultfd on some memory range.
Signed-off-by: Andrea Arcangeli
---
include/linux/mm.h | 2 +-
mm/madvise.c | 3 ++-
This implements the uABI of UFFDIO_COPY and UFFDIO_ZEROPAGE.
Signed-off-by: Andrea Arcangeli
---
include/uapi/linux/userfaultfd.h | 46 +++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux
to know when there are new pending userfaults to be
read (POLLIN).
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 977 +++
1 file changed, 977 insertions(+)
create mode 100644 fs/userfaultfd.c
diff --git a/fs/userfaultfd.c b/fs
remap_pages is the lowlevel mm helper needed to implement
UFFDIO_REMAP.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 17 ++
mm/huge_memory.c | 120 ++
mm/userfaultfd.c | 526 ++
3 files changed
userfaultfd needs to wake all waitqueues (pass 0 as nr parameter),
instead of the current hardcoded 1 (that would wake just the first
waitqueue in the head list).
Signed-off-by: Andrea Arcangeli
---
include/linux/wait.h | 5 +++--
kernel/sched/wait.c | 7 ---
net/sunrpc/sched.c | 2 +-
3
Kernel header defining the methods needed by the VM common code to
interact with the userfaultfd.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 79 +++
1 file changed, 79 insertions(+)
create mode 100644 include/linux
sed as parameter so the "read|write"
kind of fault can be passed to userland.
Signed-off-by: Andrea Arcangeli
---
mm/huge_memory.c | 68 ++--
mm/memory.c | 16 +
2 files changed, 62 insertions(+), 22 deletions(-)
di
These two ioctl allows to either atomically copy or to map zeropages
into the virtual address space. This is used by the thread that opened
the userfaultfd to resolve the userfaults.
Signed-off-by: Andrea Arcangeli
---
fs/userfaultfd.c | 100
This implements mcopy_atomic and mfill_zeropage that are the lowlevel
VM methods that are invoked respectively by the UFFDIO_COPY and
UFFDIO_ZEROPAGE userfaultfd commands.
Signed-off-by: Andrea Arcangeli
---
include/linux/userfaultfd_k.h | 6 +
mm/Makefile | 1 +
mm
This activates the userfaultfd syscall.
Signed-off-by: Andrea Arcangeli
---
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/asm/unistd.h | 2 +-
arch/powerpc/include/uapi/asm/unistd.h | 1 +
arch/x86/syscalls/syscall_32.tbl | 1 +
arch/x86/syscalls/syscall_64.tbl
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