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Message-Id: <200808020054.21088.rjw@sisk.pl>
Date: Sat, 2 Aug 2008 00:54:19 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Matt Helsley <matthltc@...ibm.com>
Cc: Cedric Le Goater <clg@...ibm.com>,
Nigel Cunningham <ncunningham@...a.org.au>,
Andrew Morton <akpm@...ux-foundation.org>,
Paul Menage <menage@...gle.com>,
Li Zefan <lizf@...fujitsu.com>,
Linux-Kernel <linux-kernel@...r.kernel.org>,
Linux Containers <containers@...ts.linux-foundation.org>,
linux-pm@...ts.linux-foundation.org, Pavel Machek <pavel@...e.cz>,
"Serge E. Hallyn" <serue@...ibm.com>
Subject: Re: [PATCH 1/6] Container Freezer: Add TIF_FREEZE flag to all architectures
On Saturday, 2 of August 2008, Matt Helsley wrote:
>
> On Fri, 2008-08-01 at 14:32 +0200, Cedric Le Goater wrote:
> > Nigel Cunningham wrote:
> > > Hi.
> > >
> > > On Thu, 2008-07-31 at 22:07 -0700, Matt Helsley wrote:
> > >> This patch is the first step in making the refrigerator() available
> > >> to all architectures, even for those without power management.
> > >>
> > >> The purpose of such a change is to be able to use the refrigerator()
> > >> in a new control group subsystem which will implement a control group
> > >> freezer.
> > >
> > > Is there a reason for always using 19, rather than just the next
> > > available bit?
> >
> > At the time I did the patch, it was to be consistent with the other
> > arches supporting suspend but this can not be true anymore. So we might
> > as well just use the next available bit as you suggest.
> >
> > Thanks,
> >
> > C.
>
> This is a good point.
>
> I did a quick survey of the thread_info*.h headers. Most archs appear
> to use the MSW/LSW to distinguish "pending work-to-be-done" (LSW) vs.
> other flags (MSW). This explains most of the gaps in thread flag
> assignment. In some other cases the bits are allocated based on whether
> the arch asm code uses asm immediate values to test the flag. sparc64 is
> by far the most elaborate and includes some excellent comments to
> explain the situation.
>
> The gaps in allocated flag bit assignments not explained in
> thread_info*.h comments are:
>
> mips doesn't use bit 0, there's a gap between 4 and 9, and another gap
> between 24 and 31.
>
> m32r has a gap between bit 4 and bit 8.
>
> ia64 has a gap at bit 5.
>
> blackfin doesn't explicitly mention the MSW/LSW distinction but appears
> to follow it.
>
> arm also doesn't mention MSW/LSW but appears consistent with that
> explanation.
>
> avr32 makes the MSW/LSW distinction but this doesn't fully explain
> jumping from bit 8 to bit 30 unless they're allocating numbers in the
> opposite direction within the MSW (highest flag is bit 31).
>
> m68k starts at 6 and the comments don't explain why. At first glance it
> doesn't appear to be because of m68knommu. It also jumps from bit 7 to
> bit 14 without explanation and appears to not follow the MSW/LSW
> convention.
>
> cris has an inexplicable gap between bit 3 and bit 9.
>
> s390 has a gap at bit 1. It appears to follow the MSW/LSW distinction
> but doesn't mention it in a comment.
>
> x86 has a gap at bit 9.
>
> "sparc32" has a gap between 4 and 8.
>
> So I've modified the flag numbers to follow apparent conventions of each
> arch as best I can tell given the lack of explanation above.
> ------------
> From: Cedric Le Goater <clg@...ibm.com>
> Subject: Container Freezer: Add TIF_FREEZE flag to all architectures
>
> This patch is the first step in making the refrigerator() available
> to all architectures, even for those without power management.
>
> The purpose of such a change is to be able to use the refrigerator()
> in a new control group subsystem which will implement a control group
> freezer.
>
> Signed-off-by: Cedric Le Goater <clg@...ibm.com>
> Signed-off-by: Matt Helsley <matthltc@...ibm.com>
> Acked-by: Pavel Machek <pavel@...e.cz>
> Acked-by: Serge E. Hallyn <serue@...ibm.com>
> Tested-by: Matt Helsley <matthltc@...ibm.com>
Acked-by: Rafael J. Wysocki <rjw@...k.pl>
> ---
> arch/parisc/include/asm/thread_info.h | 2 ++
> arch/sparc/include/asm/thread_info_32.h | 2 ++
> arch/sparc/include/asm/thread_info_64.h | 2 ++
> include/asm-alpha/thread_info.h | 2 ++
> include/asm-avr32/thread_info.h | 1 +
> include/asm-cris/thread_info.h | 2 ++
> include/asm-h8300/thread_info.h | 2 ++
> include/asm-m68k/thread_info.h | 1 +
> include/asm-m68knommu/thread_info.h | 2 ++
> include/asm-s390/thread_info.h | 2 ++
> include/asm-um/thread_info.h | 2 ++
> include/asm-xtensa/thread_info.h | 2 ++
> 12 files changed, 22 insertions(+)
>
> Index: linux-2.6.27-rc1-mm1/arch/sparc/include/asm/thread_info_32.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/arch/sparc/include/asm/thread_info_32.h
> +++ linux-2.6.27-rc1-mm1/arch/sparc/include/asm/thread_info_32.h
> @@ -139,6 +139,7 @@ BTFIXUPDEF_CALL(void, free_thread_info,
> #define TIF_POLLING_NRFLAG 9 /* true if poll_idle() is polling
> * TIF_NEED_RESCHED */
> #define TIF_MEMDIE 10
> +#define TIF_FREEZE 11 /* is freezing for suspend */
>
> /* as above, but as bit values */
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> @@ -152,6 +153,7 @@ BTFIXUPDEF_CALL(void, free_thread_info,
> #define _TIF_DO_NOTIFY_RESUME_MASK (_TIF_NOTIFY_RESUME | \
> _TIF_SIGPENDING | \
> _TIF_RESTORE_SIGMASK)
> +#define TIF_FREEZE (1<<TIF_FREEZE)
>
> #endif /* __KERNEL__ */
>
> Index: linux-2.6.27-rc1-mm1/arch/sparc/include/asm/thread_info_64.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/arch/sparc/include/asm/thread_info_64.h
> +++ linux-2.6.27-rc1-mm1/arch/sparc/include/asm/thread_info_64.h
> @@ -237,6 +237,7 @@ register struct thread_info *current_thr
> #define TIF_ABI_PENDING 12
> #define TIF_MEMDIE 13
> #define TIF_POLLING_NRFLAG 14
> +#define TIF_FREEZE 15 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
> @@ -249,6 +250,7 @@ register struct thread_info *current_thr
> #define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
> #define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #define _TIF_USER_WORK_MASK ((0xff << TI_FLAG_WSAVED_SHIFT) | \
> _TIF_DO_NOTIFY_RESUME_MASK | \
> Index: linux-2.6.27-rc1-mm1/include/asm-alpha/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-alpha/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-alpha/thread_info.h
> @@ -74,12 +74,14 @@ register struct thread_info *__current_t
> #define TIF_UAC_SIGBUS 7
> #define TIF_MEMDIE 8
> #define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal */
> +#define TIF_FREEZE 16 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
> #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> #define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> /* Work to do on interrupt/exception return. */
> #define _TIF_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
> Index: linux-2.6.27-rc1-mm1/include/asm-avr32/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-avr32/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-avr32/thread_info.h
> @@ -96,6 +96,7 @@ static inline struct thread_info *curren
> #define _TIF_MEMDIE (1 << TIF_MEMDIE)
> #define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
> #define _TIF_CPU_GOING_TO_SLEEP (1 << TIF_CPU_GOING_TO_SLEEP)
> +#define _TIF_FREEZE (1 << TIF_FREEZE)
>
> /* Note: The masks below must never span more than 16 bits! */
>
> Index: linux-2.6.27-rc1-mm1/include/asm-cris/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-cris/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-cris/thread_info.h
> @@ -88,6 +88,7 @@ struct thread_info {
> #define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
> #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
> #define TIF_MEMDIE 17
> +#define TIF_FREEZE 18 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
> @@ -95,6 +96,7 @@ struct thread_info {
> #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
> #define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
> #define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
> Index: linux-2.6.27-rc1-mm1/include/asm-h8300/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-h8300/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-h8300/thread_info.h
> @@ -89,6 +89,7 @@ static inline struct thread_info *curren
> TIF_NEED_RESCHED */
> #define TIF_MEMDIE 4
> #define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
> +#define TIF_FREEZE 16 /* is freezing for suspend */
>
> /* as above, but as bit values */
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> @@ -96,6 +97,7 @@ static inline struct thread_info *curren
> #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> #define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
>
> Index: linux-2.6.27-rc1-mm1/include/asm-m68k/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-m68k/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-m68k/thread_info.h
> @@ -52,5 +52,6 @@ struct thread_info {
> #define TIF_DELAYED_TRACE 14 /* single step a syscall */
> #define TIF_SYSCALL_TRACE 15 /* syscall trace active */
> #define TIF_MEMDIE 16
> +#define TIF_FREEZE 17 /* thread is freezing for suspend */
>
> #endif /* _ASM_M68K_THREAD_INFO_H */
> Index: linux-2.6.27-rc1-mm1/include/asm-m68knommu/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-m68knommu/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-m68knommu/thread_info.h
> @@ -84,12 +84,14 @@ static inline struct thread_info *curren
> #define TIF_POLLING_NRFLAG 3 /* true if poll_idle() is polling
> TIF_NEED_RESCHED */
> #define TIF_MEMDIE 4
> +#define TIF_FREEZE 16 /* is freezing for suspend */
>
> /* as above, but as bit values */
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
> #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
>
> Index: linux-2.6.27-rc1-mm1/include/asm-s390/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-s390/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-s390/thread_info.h
> @@ -98,6 +98,7 @@ static inline struct thread_info *curren
> #define TIF_31BIT 18 /* 32bit process */
> #define TIF_MEMDIE 19
> #define TIF_RESTORE_SIGMASK 20 /* restore signal mask in do_signal() */
> +#define TIF_FREEZE 21 /* thread is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
> @@ -110,6 +111,7 @@ static inline struct thread_info *curren
> #define _TIF_USEDFPU (1<<TIF_USEDFPU)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> #define _TIF_31BIT (1<<TIF_31BIT)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #endif /* __KERNEL__ */
>
> Index: linux-2.6.27-rc1-mm1/include/asm-um/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-um/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-um/thread_info.h
> @@ -69,6 +69,7 @@ static inline struct thread_info *curren
> #define TIF_MEMDIE 5
> #define TIF_SYSCALL_AUDIT 6
> #define TIF_RESTORE_SIGMASK 7
> +#define TIF_FREEZE 16 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
> #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
> @@ -77,5 +78,6 @@ static inline struct thread_info *curren
> #define _TIF_MEMDIE (1 << TIF_MEMDIE)
> #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
> #define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
> +#define _TIF_FREEZE (1 << TIF_FREEZE)
>
> #endif
> Index: linux-2.6.27-rc1-mm1/include/asm-xtensa/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/include/asm-xtensa/thread_info.h
> +++ linux-2.6.27-rc1-mm1/include/asm-xtensa/thread_info.h
> @@ -134,6 +134,7 @@ static inline struct thread_info *curren
> #define TIF_MEMDIE 5
> #define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */
> #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
> +#define TIF_FREEZE 17 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
> #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
> @@ -142,6 +143,7 @@ static inline struct thread_info *curren
> #define _TIF_IRET (1<<TIF_IRET)
> #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
> #define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
> +#define _TIF_FREEZE (1<<TIF_FREEZE)
>
> #define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
> #define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
> Index: linux-2.6.27-rc1-mm1/arch/parisc/include/asm/thread_info.h
> ===================================================================
> --- linux-2.6.27-rc1-mm1.orig/arch/parisc/include/asm/thread_info.h
> +++ linux-2.6.27-rc1-mm1/arch/parisc/include/asm/thread_info.h
> @@ -58,6 +58,7 @@ struct thread_info {
> #define TIF_32BIT 4 /* 32 bit binary */
> #define TIF_MEMDIE 5
> #define TIF_RESTORE_SIGMASK 6 /* restore saved signal mask */
> +#define TIF_FREEZE 7 /* is freezing for suspend */
>
> #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
> #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
> @@ -65,6 +66,7 @@ struct thread_info {
> #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
> #define _TIF_32BIT (1 << TIF_32BIT)
> #define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
> +#define _TIF_FREEZE (1 << TIF_FREEZE)
>
> #define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | \
> _TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)
>
>
>
>
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