diff mbox

[V4,2/6] mm: mlock: Add new mlock, munlock, and munlockall system calls

Message ID 20150721134441.d69e4e1099bd43e56835b3c5@linux-foundation.org (mailing list archive)
State New, archived
Headers show

Commit Message

Andrew Morton July 21, 2015, 8:44 p.m. UTC
On Tue, 21 Jul 2015 15:59:37 -0400 Eric B Munson <emunson@akamai.com> wrote:

> With the refactored mlock code, introduce new system calls for mlock,
> munlock, and munlockall.  The new calls will allow the user to specify
> what lock states are being added or cleared.  mlock2 and munlock2 are
> trivial at the moment, but a follow on patch will add a new mlock state
> making them useful.
> 
> munlock2 addresses a limitation of the current implementation.  If a
> user calls mlockall(MCL_CURRENT | MCL_FUTURE) and then later decides
> that MCL_FUTURE should be removed, they would have to call munlockall()
> followed by mlockall(MCL_CURRENT) which could potentially be very
> expensive.  The new munlockall2 system call allows a user to simply
> clear the MCL_FUTURE flag.

This is hard.  Maybe we shouldn't have wired up anything other than
x86.  That's what we usually do with new syscalls.

You appear to have missed
mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix.patch:

Comments

Michael Ellerman July 22, 2015, 1:25 a.m. UTC | #1
On Tue, 2015-07-21 at 13:44 -0700, Andrew Morton wrote:
> On Tue, 21 Jul 2015 15:59:37 -0400 Eric B Munson <emunson@akamai.com> wrote:
> 
> > With the refactored mlock code, introduce new system calls for mlock,
> > munlock, and munlockall.  The new calls will allow the user to specify
> > what lock states are being added or cleared.  mlock2 and munlock2 are
> > trivial at the moment, but a follow on patch will add a new mlock state
> > making them useful.
> > 
> > munlock2 addresses a limitation of the current implementation.  If a
> > user calls mlockall(MCL_CURRENT | MCL_FUTURE) and then later decides
> > that MCL_FUTURE should be removed, they would have to call munlockall()
> > followed by mlockall(MCL_CURRENT) which could potentially be very
> > expensive.  The new munlockall2 system call allows a user to simply
> > clear the MCL_FUTURE flag.
> 
> This is hard.  Maybe we shouldn't have wired up anything other than
> x86.  That's what we usually do with new syscalls.

Yeah I think so.

You haven't wired it up properly on powerpc, but I haven't mentioned it because
I'd rather we did it.

cheers
Eric B Munson July 22, 2015, 2:15 p.m. UTC | #2
On Wed, 22 Jul 2015, Michael Ellerman wrote:

> On Tue, 2015-07-21 at 13:44 -0700, Andrew Morton wrote:
> > On Tue, 21 Jul 2015 15:59:37 -0400 Eric B Munson <emunson@akamai.com> wrote:
> > 
> > > With the refactored mlock code, introduce new system calls for mlock,
> > > munlock, and munlockall.  The new calls will allow the user to specify
> > > what lock states are being added or cleared.  mlock2 and munlock2 are
> > > trivial at the moment, but a follow on patch will add a new mlock state
> > > making them useful.
> > > 
> > > munlock2 addresses a limitation of the current implementation.  If a
> > > user calls mlockall(MCL_CURRENT | MCL_FUTURE) and then later decides
> > > that MCL_FUTURE should be removed, they would have to call munlockall()
> > > followed by mlockall(MCL_CURRENT) which could potentially be very
> > > expensive.  The new munlockall2 system call allows a user to simply
> > > clear the MCL_FUTURE flag.
> > 
> > This is hard.  Maybe we shouldn't have wired up anything other than
> > x86.  That's what we usually do with new syscalls.
> 
> Yeah I think so.
> 
> You haven't wired it up properly on powerpc, but I haven't mentioned it because
> I'd rather we did it.
> 
> cheers

It looks like I will be spinning a V5, so I will drop all but the x86
system calls additions in that version.
Ralf Baechle July 23, 2015, 6:58 a.m. UTC | #3
On Wed, Jul 22, 2015 at 10:15:01AM -0400, Eric B Munson wrote:

> > 
> > You haven't wired it up properly on powerpc, but I haven't mentioned it because
> > I'd rather we did it.
> > 
> > cheers
> 
> It looks like I will be spinning a V5, so I will drop all but the x86
> system calls additions in that version.

The MIPS bits are looking good however, so

Acked-by: Ralf Baechle <ralf@linux-mips.org>

With my ack, will you keep them or maybe carry them as a separate patch?

Cheers,

  Ralf
Eric B Munson July 24, 2015, 2:39 p.m. UTC | #4
On Thu, 23 Jul 2015, Ralf Baechle wrote:

> On Wed, Jul 22, 2015 at 10:15:01AM -0400, Eric B Munson wrote:
> 
> > > 
> > > You haven't wired it up properly on powerpc, but I haven't mentioned it because
> > > I'd rather we did it.
> > > 
> > > cheers
> > 
> > It looks like I will be spinning a V5, so I will drop all but the x86
> > system calls additions in that version.
> 
> The MIPS bits are looking good however, so
> 
> Acked-by: Ralf Baechle <ralf@linux-mips.org>
> 
> With my ack, will you keep them or maybe carry them as a separate patch?

I will keep the MIPS additions as a separate patch in the series, though
I have dropped two of the new syscalls after some discussion.  So I will
not include your ack on the new patch.

Eric
Guenter Roeck July 24, 2015, 3:46 p.m. UTC | #5
On 07/24/2015 07:39 AM, Eric B Munson wrote:
> On Thu, 23 Jul 2015, Ralf Baechle wrote:
>
>> On Wed, Jul 22, 2015 at 10:15:01AM -0400, Eric B Munson wrote:
>>
>>>>
>>>> You haven't wired it up properly on powerpc, but I haven't mentioned it because
>>>> I'd rather we did it.
>>>>
>>>> cheers
>>>
>>> It looks like I will be spinning a V5, so I will drop all but the x86
>>> system calls additions in that version.
>>
>> The MIPS bits are looking good however, so
>>
>> Acked-by: Ralf Baechle <ralf@linux-mips.org>
>>
>> With my ack, will you keep them or maybe carry them as a separate patch?
>
> I will keep the MIPS additions as a separate patch in the series, though
> I have dropped two of the new syscalls after some discussion.  So I will
> not include your ack on the new patch.
>
> Eric
>

Hi Eric,

next-20150724 still has some failures due to this patch set. Are those
being looked at (I know parisc builds fail, but there may be others) ?

Thanks,
Guenter
Eric B Munson July 24, 2015, 3:53 p.m. UTC | #6
On Fri, 24 Jul 2015, Guenter Roeck wrote:

> On 07/24/2015 07:39 AM, Eric B Munson wrote:
> >On Thu, 23 Jul 2015, Ralf Baechle wrote:
> >
> >>On Wed, Jul 22, 2015 at 10:15:01AM -0400, Eric B Munson wrote:
> >>
> >>>>
> >>>>You haven't wired it up properly on powerpc, but I haven't mentioned it because
> >>>>I'd rather we did it.
> >>>>
> >>>>cheers
> >>>
> >>>It looks like I will be spinning a V5, so I will drop all but the x86
> >>>system calls additions in that version.
> >>
> >>The MIPS bits are looking good however, so
> >>
> >>Acked-by: Ralf Baechle <ralf@linux-mips.org>
> >>
> >>With my ack, will you keep them or maybe carry them as a separate patch?
> >
> >I will keep the MIPS additions as a separate patch in the series, though
> >I have dropped two of the new syscalls after some discussion.  So I will
> >not include your ack on the new patch.
> >
> >Eric
> >
> 
> Hi Eric,
> 
> next-20150724 still has some failures due to this patch set. Are those
> being looked at (I know parisc builds fail, but there may be others) ?
> 
> Thanks,
> Guenter

Guenter,

Yes, the next respin will drop all new arch syscall entries except
x86[_64] and MIPS.  I will leave it up to arch maintainers to add the
entries.

Eric
diff mbox

Patch

--- a/arch/arm64/include/asm/unistd.h~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix
+++ a/arch/arm64/include/asm/unistd.h
@@ -44,7 +44,7 @@ 
 #define __ARM_NR_compat_cacheflush	(__ARM_NR_COMPAT_BASE+2)
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE+5)
 
-#define __NR_compat_syscalls		388
+#define __NR_compat_syscalls		391
 #endif
 
 #define __ARCH_WANT_SYS_CLONE


And mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2.patch:


From: Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2

can we just remove the s390 bits which cause the breakage?
I will wire up the syscalls as soon as the patch set gets merged.

Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Eric B Munson <emunson@akamai.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/s390/kernel/syscalls.S |    3 ---
 1 file changed, 3 deletions(-)

diff -puN arch/s390/kernel/syscalls.S~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2 arch/s390/kernel/syscalls.S
--- a/arch/s390/kernel/syscalls.S~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2
+++ a/arch/s390/kernel/syscalls.S
@@ -363,6 +363,3 @@  SYSCALL(sys_bpf,compat_sys_bpf)
 SYSCALL(sys_s390_pci_mmio_write,compat_sys_s390_pci_mmio_write)
 SYSCALL(sys_s390_pci_mmio_read,compat_sys_s390_pci_mmio_read)
 SYSCALL(sys_execveat,compat_sys_execveat)
-SYSCALL(sys_mlock2,compat_sys_mlock2)			/* 355 */
-SYSCALL(sys_munlock2,compat_sys_munlock2)
-SYSCALL(sys_munlockall2,compat_sys_munlockall2)