Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-16 Thread Neil Horman 
On Sun, Apr 15, 2018 at 05:13:13PM +0200, Gaëtan Rivet wrote:
> Hello Neil,
> 
> On Sat, Apr 14, 2018 at 02:45:45PM -0400, Neil Horman wrote:
> > On Fri, Apr 13, 2018 at 02:55:11PM +0200, Gaëtan Rivet wrote:
> > > Hi Shreyansh,
> > > 
> > > On Fri, Apr 13, 2018 at 06:22:43PM +0530, Shreyansh Jain wrote:
> > > > On Friday 13 April 2018 05:12 PM, Neil Horman wrote:
> > > > > On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:
> > > > > > Hello Neil,
> > > > > > 
> > > > > > On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> > > > > > > On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > > > > > > > Build a central list to quickly see each used priorities for
> > > > > > > > constructors, allowing to verify that they are both above 100 
> > > > > > > > and in the
> > > > > > > > proper order.
> > > > > > > > 
> > > > > > > > Signed-off-by: Gaetan Rivet 
> > > > > > > > Acked-by: Neil Horman 
> > > > > > > > Acked-by: Shreyansh Jain 
> > > > > > > > ---
> > > > > > > >   lib/librte_eal/common/eal_common_log.c | 2 +-
> > > > > > > >   lib/librte_eal/common/include/rte_bus.h| 2 +-
> > > > > > > >   lib/librte_eal/common/include/rte_common.h | 8 +++-
> > > > > > > >   3 files changed, 9 insertions(+), 3 deletions(-)
> > > > > > > > 
> > > > > > > > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > > > > > > > b/lib/librte_eal/common/eal_common_log.c
> > > > > > > > index a27192620..36b9d6e08 100644
> > > > > > > > --- a/lib/librte_eal/common/eal_common_log.c
> > > > > > > > +++ b/lib/librte_eal/common/eal_common_log.c
> > > > > > > > @@ -260,7 +260,7 @@ static const struct logtype 
> > > > > > > > logtype_strings[] = {
> > > > > > > >   };
> > > > > > > >   /* Logging should be first initializer (before drivers and 
> > > > > > > > bus) */
> > > > > > > > -RTE_INIT_PRIO(rte_log_init, 101);
> > > > > > > > +RTE_INIT_PRIO(rte_log_init, LOG);
> > > > > > > >   static void
> > > > > > > >   rte_log_init(void)
> > > > > > > >   {
> > > > > > > > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > > > > > > > b/lib/librte_eal/common/include/rte_bus.h
> > > > > > > > index 6fb08341a..eb9eded4e 100644
> > > > > > > > --- a/lib/librte_eal/common/include/rte_bus.h
> > > > > > > > +++ b/lib/librte_eal/common/include/rte_bus.h
> > > > > > > > @@ -325,7 +325,7 @@ enum rte_iova_mode 
> > > > > > > > rte_bus_get_iommu_class(void);
> > > > > > > >* The constructor has higher priority than PMD constructors.
> > > > > > > >*/
> > > > > > > >   #define RTE_REGISTER_BUS(nm, bus) \
> > > > > > > > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > > > > > > > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> > > > > > > >   static void businitfn_ ##nm(void) \
> > > > > > > >   {\
> > > > > > > > (bus).name = RTE_STR(nm);\
> > > > > > > > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > > > > > > > b/lib/librte_eal/common/include/rte_common.h
> > > > > > > > index 6c5bc5a76..8f04518f7 100644
> > > > > > > > --- a/lib/librte_eal/common/include/rte_common.h
> > > > > > > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > > > > > > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> > > > > > > >*/
> > > > > > > >   #define RTE_SET_USED(x) (void)(x)
> > > > > > > > +#define RTE_PRIORITY_LOG 101
> > > > > > > > +#define RTE_PRIORITY_BUS 110
> > > > > > > > +
> > > > > > > > +#define RTE_PRIO(prio) \
> > > > > > > > +   RTE_PRIORITY_ ## prio
> > > > > > > > +
> > > > > > > >   /**
> > > > > > > >* Run function before main() with low priority.
> > > > > > > >*
> > > > > > > > @@ -102,7 +108,7 @@ static void __attribute__((constructor, 
> > > > > > > > used)) func(void)
> > > > > > > >*   Lowest number is the first to run.
> > > > > > > >*/
> > > > > > > >   #define RTE_INIT_PRIO(func, prio) \
> > > > > > > > -static void __attribute__((constructor(prio), used)) func(void)
> > > > > > > > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) 
> > > > > > > > func(void)
> > > > > > > It just occured to me, that perhaps you should add a 
> > > > > > > RTE_PRORITY_LAST priority,
> > > > > > > and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) 
> > > > > > > for clarity.  I
> > > > > > > presume that constructors with no explicit priority run last, but 
> > > > > > > the gcc
> > > > > > > manual doesn't explicitly say that.  It would be a heck of a bug 
> > > > > > > to track down
> > > > > > > if somehow unprioritized constructors ran early.
> > > > > > > 
> > > > > > > Neil
> > > > > > > 
> > > > > > 
> > > > > > While certainly poorly documented, the behavior is well-defined. I 
> > > > > > don't see
> > > > > > a situation where the bug you describe could arise.
> > > > > > 
> > > > > > Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
> > > > > > justified to add it. If you still think it is useful, I will do it.
> > > > > > 
> > > > > It was more just a way to unify the macros is all, probabl

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-15 Thread Gaëtan Rivet 
Hello Neil,

On Sat, Apr 14, 2018 at 02:45:45PM -0400, Neil Horman wrote:
> On Fri, Apr 13, 2018 at 02:55:11PM +0200, Gaëtan Rivet wrote:
> > Hi Shreyansh,
> > 
> > On Fri, Apr 13, 2018 at 06:22:43PM +0530, Shreyansh Jain wrote:
> > > On Friday 13 April 2018 05:12 PM, Neil Horman wrote:
> > > > On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:
> > > > > Hello Neil,
> > > > > 
> > > > > On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> > > > > > On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > > > > > > Build a central list to quickly see each used priorities for
> > > > > > > constructors, allowing to verify that they are both above 100 and 
> > > > > > > in the
> > > > > > > proper order.
> > > > > > > 
> > > > > > > Signed-off-by: Gaetan Rivet 
> > > > > > > Acked-by: Neil Horman 
> > > > > > > Acked-by: Shreyansh Jain 
> > > > > > > ---
> > > > > > >   lib/librte_eal/common/eal_common_log.c | 2 +-
> > > > > > >   lib/librte_eal/common/include/rte_bus.h| 2 +-
> > > > > > >   lib/librte_eal/common/include/rte_common.h | 8 +++-
> > > > > > >   3 files changed, 9 insertions(+), 3 deletions(-)
> > > > > > > 
> > > > > > > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > > > > > > b/lib/librte_eal/common/eal_common_log.c
> > > > > > > index a27192620..36b9d6e08 100644
> > > > > > > --- a/lib/librte_eal/common/eal_common_log.c
> > > > > > > +++ b/lib/librte_eal/common/eal_common_log.c
> > > > > > > @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] 
> > > > > > > = {
> > > > > > >   };
> > > > > > >   /* Logging should be first initializer (before drivers and bus) 
> > > > > > > */
> > > > > > > -RTE_INIT_PRIO(rte_log_init, 101);
> > > > > > > +RTE_INIT_PRIO(rte_log_init, LOG);
> > > > > > >   static void
> > > > > > >   rte_log_init(void)
> > > > > > >   {
> > > > > > > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > > > > > > b/lib/librte_eal/common/include/rte_bus.h
> > > > > > > index 6fb08341a..eb9eded4e 100644
> > > > > > > --- a/lib/librte_eal/common/include/rte_bus.h
> > > > > > > +++ b/lib/librte_eal/common/include/rte_bus.h
> > > > > > > @@ -325,7 +325,7 @@ enum rte_iova_mode 
> > > > > > > rte_bus_get_iommu_class(void);
> > > > > > >* The constructor has higher priority than PMD constructors.
> > > > > > >*/
> > > > > > >   #define RTE_REGISTER_BUS(nm, bus) \
> > > > > > > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > > > > > > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> > > > > > >   static void businitfn_ ##nm(void) \
> > > > > > >   {\
> > > > > > >   (bus).name = RTE_STR(nm);\
> > > > > > > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > > > > > > b/lib/librte_eal/common/include/rte_common.h
> > > > > > > index 6c5bc5a76..8f04518f7 100644
> > > > > > > --- a/lib/librte_eal/common/include/rte_common.h
> > > > > > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > > > > > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> > > > > > >*/
> > > > > > >   #define RTE_SET_USED(x) (void)(x)
> > > > > > > +#define RTE_PRIORITY_LOG 101
> > > > > > > +#define RTE_PRIORITY_BUS 110
> > > > > > > +
> > > > > > > +#define RTE_PRIO(prio) \
> > > > > > > + RTE_PRIORITY_ ## prio
> > > > > > > +
> > > > > > >   /**
> > > > > > >* Run function before main() with low priority.
> > > > > > >*
> > > > > > > @@ -102,7 +108,7 @@ static void __attribute__((constructor, 
> > > > > > > used)) func(void)
> > > > > > >*   Lowest number is the first to run.
> > > > > > >*/
> > > > > > >   #define RTE_INIT_PRIO(func, prio) \
> > > > > > > -static void __attribute__((constructor(prio), used)) func(void)
> > > > > > > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) 
> > > > > > > func(void)
> > > > > > It just occured to me, that perhaps you should add a 
> > > > > > RTE_PRORITY_LAST priority,
> > > > > > and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for 
> > > > > > clarity.  I
> > > > > > presume that constructors with no explicit priority run last, but 
> > > > > > the gcc
> > > > > > manual doesn't explicitly say that.  It would be a heck of a bug to 
> > > > > > track down
> > > > > > if somehow unprioritized constructors ran early.
> > > > > > 
> > > > > > Neil
> > > > > > 
> > > > > 
> > > > > While certainly poorly documented, the behavior is well-defined. I 
> > > > > don't see
> > > > > a situation where the bug you describe could arise.
> > > > > 
> > > > > Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
> > > > > justified to add it. If you still think it is useful, I will do it.
> > > > > 
> > > > It was more just a way to unify the macros is all, probably not 
> > > > important.
> > > > 
> > > > > I'd be curious to hear if anyone has had issues of this kind.
> > > > > 
> > > > I've not had any, but I was suprised to see that the gcc manual didn't
> > > > explicitly call out the implied priority of unprioritized construct

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-14 Thread Neil Horman 
On Fri, Apr 13, 2018 at 02:55:11PM +0200, Gaëtan Rivet wrote:
> Hi Shreyansh,
> 
> On Fri, Apr 13, 2018 at 06:22:43PM +0530, Shreyansh Jain wrote:
> > On Friday 13 April 2018 05:12 PM, Neil Horman wrote:
> > > On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:
> > > > Hello Neil,
> > > > 
> > > > On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> > > > > On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > > > > > Build a central list to quickly see each used priorities for
> > > > > > constructors, allowing to verify that they are both above 100 and 
> > > > > > in the
> > > > > > proper order.
> > > > > > 
> > > > > > Signed-off-by: Gaetan Rivet 
> > > > > > Acked-by: Neil Horman 
> > > > > > Acked-by: Shreyansh Jain 
> > > > > > ---
> > > > > >   lib/librte_eal/common/eal_common_log.c | 2 +-
> > > > > >   lib/librte_eal/common/include/rte_bus.h| 2 +-
> > > > > >   lib/librte_eal/common/include/rte_common.h | 8 +++-
> > > > > >   3 files changed, 9 insertions(+), 3 deletions(-)
> > > > > > 
> > > > > > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > > > > > b/lib/librte_eal/common/eal_common_log.c
> > > > > > index a27192620..36b9d6e08 100644
> > > > > > --- a/lib/librte_eal/common/eal_common_log.c
> > > > > > +++ b/lib/librte_eal/common/eal_common_log.c
> > > > > > @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = 
> > > > > > {
> > > > > >   };
> > > > > >   /* Logging should be first initializer (before drivers and bus) */
> > > > > > -RTE_INIT_PRIO(rte_log_init, 101);
> > > > > > +RTE_INIT_PRIO(rte_log_init, LOG);
> > > > > >   static void
> > > > > >   rte_log_init(void)
> > > > > >   {
> > > > > > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > > > > > b/lib/librte_eal/common/include/rte_bus.h
> > > > > > index 6fb08341a..eb9eded4e 100644
> > > > > > --- a/lib/librte_eal/common/include/rte_bus.h
> > > > > > +++ b/lib/librte_eal/common/include/rte_bus.h
> > > > > > @@ -325,7 +325,7 @@ enum rte_iova_mode 
> > > > > > rte_bus_get_iommu_class(void);
> > > > > >* The constructor has higher priority than PMD constructors.
> > > > > >*/
> > > > > >   #define RTE_REGISTER_BUS(nm, bus) \
> > > > > > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > > > > > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> > > > > >   static void businitfn_ ##nm(void) \
> > > > > >   {\
> > > > > > (bus).name = RTE_STR(nm);\
> > > > > > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > > > > > b/lib/librte_eal/common/include/rte_common.h
> > > > > > index 6c5bc5a76..8f04518f7 100644
> > > > > > --- a/lib/librte_eal/common/include/rte_common.h
> > > > > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > > > > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> > > > > >*/
> > > > > >   #define RTE_SET_USED(x) (void)(x)
> > > > > > +#define RTE_PRIORITY_LOG 101
> > > > > > +#define RTE_PRIORITY_BUS 110
> > > > > > +
> > > > > > +#define RTE_PRIO(prio) \
> > > > > > +   RTE_PRIORITY_ ## prio
> > > > > > +
> > > > > >   /**
> > > > > >* Run function before main() with low priority.
> > > > > >*
> > > > > > @@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) 
> > > > > > func(void)
> > > > > >*   Lowest number is the first to run.
> > > > > >*/
> > > > > >   #define RTE_INIT_PRIO(func, prio) \
> > > > > > -static void __attribute__((constructor(prio), used)) func(void)
> > > > > > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) 
> > > > > > func(void)
> > > > > It just occured to me, that perhaps you should add a RTE_PRORITY_LAST 
> > > > > priority,
> > > > > and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for 
> > > > > clarity.  I
> > > > > presume that constructors with no explicit priority run last, but the 
> > > > > gcc
> > > > > manual doesn't explicitly say that.  It would be a heck of a bug to 
> > > > > track down
> > > > > if somehow unprioritized constructors ran early.
> > > > > 
> > > > > Neil
> > > > > 
> > > > 
> > > > While certainly poorly documented, the behavior is well-defined. I 
> > > > don't see
> > > > a situation where the bug you describe could arise.
> > > > 
> > > > Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
> > > > justified to add it. If you still think it is useful, I will do it.
> > > > 
> > > It was more just a way to unify the macros is all, probably not important.
> > > 
> > > > I'd be curious to hear if anyone has had issues of this kind.
> > > > 
> > > I've not had any, but I was suprised to see that the gcc manual didn't
> > > explicitly call out the implied priority of unprioritized constructors
> > 
> > I (tried to) looked into the gcc code base. It seems that when priority is
> > not defined, DEFAULT_INIT_PRIORITY 65536, is used.
> > 
> > --->8--- gcc/collect2.c ---
> >   /* Extract init_p number from ctor/dtor name.  */
> >   pri = atoi (name + pos);
> >   return pri ? pri : DEFAULT_INIT_PRIOR

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-13 Thread Gaëtan Rivet 
Hi Shreyansh,

On Fri, Apr 13, 2018 at 06:22:43PM +0530, Shreyansh Jain wrote:
> On Friday 13 April 2018 05:12 PM, Neil Horman wrote:
> > On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:
> > > Hello Neil,
> > > 
> > > On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> > > > On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > > > > Build a central list to quickly see each used priorities for
> > > > > constructors, allowing to verify that they are both above 100 and in 
> > > > > the
> > > > > proper order.
> > > > > 
> > > > > Signed-off-by: Gaetan Rivet 
> > > > > Acked-by: Neil Horman 
> > > > > Acked-by: Shreyansh Jain 
> > > > > ---
> > > > >   lib/librte_eal/common/eal_common_log.c | 2 +-
> > > > >   lib/librte_eal/common/include/rte_bus.h| 2 +-
> > > > >   lib/librte_eal/common/include/rte_common.h | 8 +++-
> > > > >   3 files changed, 9 insertions(+), 3 deletions(-)
> > > > > 
> > > > > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > > > > b/lib/librte_eal/common/eal_common_log.c
> > > > > index a27192620..36b9d6e08 100644
> > > > > --- a/lib/librte_eal/common/eal_common_log.c
> > > > > +++ b/lib/librte_eal/common/eal_common_log.c
> > > > > @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = {
> > > > >   };
> > > > >   /* Logging should be first initializer (before drivers and bus) */
> > > > > -RTE_INIT_PRIO(rte_log_init, 101);
> > > > > +RTE_INIT_PRIO(rte_log_init, LOG);
> > > > >   static void
> > > > >   rte_log_init(void)
> > > > >   {
> > > > > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > > > > b/lib/librte_eal/common/include/rte_bus.h
> > > > > index 6fb08341a..eb9eded4e 100644
> > > > > --- a/lib/librte_eal/common/include/rte_bus.h
> > > > > +++ b/lib/librte_eal/common/include/rte_bus.h
> > > > > @@ -325,7 +325,7 @@ enum rte_iova_mode rte_bus_get_iommu_class(void);
> > > > >* The constructor has higher priority than PMD constructors.
> > > > >*/
> > > > >   #define RTE_REGISTER_BUS(nm, bus) \
> > > > > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > > > > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> > > > >   static void businitfn_ ##nm(void) \
> > > > >   {\
> > > > >   (bus).name = RTE_STR(nm);\
> > > > > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > > > > b/lib/librte_eal/common/include/rte_common.h
> > > > > index 6c5bc5a76..8f04518f7 100644
> > > > > --- a/lib/librte_eal/common/include/rte_common.h
> > > > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > > > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> > > > >*/
> > > > >   #define RTE_SET_USED(x) (void)(x)
> > > > > +#define RTE_PRIORITY_LOG 101
> > > > > +#define RTE_PRIORITY_BUS 110
> > > > > +
> > > > > +#define RTE_PRIO(prio) \
> > > > > + RTE_PRIORITY_ ## prio
> > > > > +
> > > > >   /**
> > > > >* Run function before main() with low priority.
> > > > >*
> > > > > @@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) 
> > > > > func(void)
> > > > >*   Lowest number is the first to run.
> > > > >*/
> > > > >   #define RTE_INIT_PRIO(func, prio) \
> > > > > -static void __attribute__((constructor(prio), used)) func(void)
> > > > > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) 
> > > > > func(void)
> > > > It just occured to me, that perhaps you should add a RTE_PRORITY_LAST 
> > > > priority,
> > > > and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for 
> > > > clarity.  I
> > > > presume that constructors with no explicit priority run last, but the 
> > > > gcc
> > > > manual doesn't explicitly say that.  It would be a heck of a bug to 
> > > > track down
> > > > if somehow unprioritized constructors ran early.
> > > > 
> > > > Neil
> > > > 
> > > 
> > > While certainly poorly documented, the behavior is well-defined. I don't 
> > > see
> > > a situation where the bug you describe could arise.
> > > 
> > > Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
> > > justified to add it. If you still think it is useful, I will do it.
> > > 
> > It was more just a way to unify the macros is all, probably not important.
> > 
> > > I'd be curious to hear if anyone has had issues of this kind.
> > > 
> > I've not had any, but I was suprised to see that the gcc manual didn't
> > explicitly call out the implied priority of unprioritized constructors
> 
> I (tried to) looked into the gcc code base. It seems that when priority is
> not defined, DEFAULT_INIT_PRIORITY 65536, is used.
> 
> --->8--- gcc/collect2.c ---
>   /* Extract init_p number from ctor/dtor name.  */
>   pri = atoi (name + pos);
>   return pri ? pri : DEFAULT_INIT_PRIORITY;
> --->8---
> 
> Though, I couldn't find any documentation for this fact - and, I can never
> be confident about gcc code.
> 
> I found one of the ARM compiler (clang) does has a policy for using
> non-specified priority as lower than specified priority. [1]
> 
> [1] 
> https://developer.arm.com/d

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-13 Thread Shreyansh Jain 

On Friday 13 April 2018 05:12 PM, Neil Horman wrote:

On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:

Hello Neil,

On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:

On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:

Build a central list to quickly see each used priorities for
constructors, allowing to verify that they are both above 100 and in the
proper order.

Signed-off-by: Gaetan Rivet 
Acked-by: Neil Horman 
Acked-by: Shreyansh Jain 
---
  lib/librte_eal/common/eal_common_log.c | 2 +-
  lib/librte_eal/common/include/rte_bus.h| 2 +-
  lib/librte_eal/common/include/rte_common.h | 8 +++-
  3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_log.c 
b/lib/librte_eal/common/eal_common_log.c
index a27192620..36b9d6e08 100644
--- a/lib/librte_eal/common/eal_common_log.c
+++ b/lib/librte_eal/common/eal_common_log.c
@@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = {
  };
  
  /* Logging should be first initializer (before drivers and bus) */

-RTE_INIT_PRIO(rte_log_init, 101);
+RTE_INIT_PRIO(rte_log_init, LOG);
  static void
  rte_log_init(void)
  {
diff --git a/lib/librte_eal/common/include/rte_bus.h 
b/lib/librte_eal/common/include/rte_bus.h
index 6fb08341a..eb9eded4e 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -325,7 +325,7 @@ enum rte_iova_mode rte_bus_get_iommu_class(void);
   * The constructor has higher priority than PMD constructors.
   */
  #define RTE_REGISTER_BUS(nm, bus) \
-RTE_INIT_PRIO(businitfn_ ##nm, 110); \
+RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
  static void businitfn_ ##nm(void) \
  {\
(bus).name = RTE_STR(nm);\
diff --git a/lib/librte_eal/common/include/rte_common.h 
b/lib/librte_eal/common/include/rte_common.h
index 6c5bc5a76..8f04518f7 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
   */
  #define RTE_SET_USED(x) (void)(x)
  
+#define RTE_PRIORITY_LOG 101

+#define RTE_PRIORITY_BUS 110
+
+#define RTE_PRIO(prio) \
+   RTE_PRIORITY_ ## prio
+
  /**
   * Run function before main() with low priority.
   *
@@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) func(void)
   *   Lowest number is the first to run.
   */
  #define RTE_INIT_PRIO(func, prio) \
-static void __attribute__((constructor(prio), used)) func(void)
+static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
  

It just occured to me, that perhaps you should add a RTE_PRORITY_LAST priority,
and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for clarity.  I
presume that constructors with no explicit priority run last, but the gcc
manual doesn't explicitly say that.  It would be a heck of a bug to track down
if somehow unprioritized constructors ran early.

Neil



While certainly poorly documented, the behavior is well-defined. I don't see
a situation where the bug you describe could arise.

Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
justified to add it. If you still think it is useful, I will do it.


It was more just a way to unify the macros is all, probably not important.


I'd be curious to hear if anyone has had issues of this kind.


I've not had any, but I was suprised to see that the gcc manual didn't
explicitly call out the implied priority of unprioritized constructors


I (tried to) looked into the gcc code base. It seems that when priority 
is not defined, DEFAULT_INIT_PRIORITY 65536, is used.


--->8--- gcc/collect2.c ---
  /* Extract init_p number from ctor/dtor name.  */
  pri = atoi (name + pos);
  return pri ? pri : DEFAULT_INIT_PRIORITY;
--->8---

Though, I couldn't find any documentation for this fact - and, I can 
never be confident about gcc code.


I found one of the ARM compiler (clang) does has a policy for using 
non-specified priority as lower than specified priority. [1]


[1] 
https://developer.arm.com/docs/dui0774/latest/compiler-specific-function-variable-and-type-attributes/__attribute__constructorpriority-function-attribute


A specified value for RTE_PRIORITY_LAST is not a bad option - it would 
help in keeping the priorities bound without relying on the unknown of 
priority for unspecified constructors.




Neil


--
Gaëtan Rivet
6WIND

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-13 Thread Neil Horman 
On Thu, Apr 12, 2018 at 11:57:47PM +0200, Gaëtan Rivet wrote:
> Hello Neil,
> 
> On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> > On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > > Build a central list to quickly see each used priorities for
> > > constructors, allowing to verify that they are both above 100 and in the
> > > proper order.
> > > 
> > > Signed-off-by: Gaetan Rivet 
> > > Acked-by: Neil Horman 
> > > Acked-by: Shreyansh Jain 
> > > ---
> > >  lib/librte_eal/common/eal_common_log.c | 2 +-
> > >  lib/librte_eal/common/include/rte_bus.h| 2 +-
> > >  lib/librte_eal/common/include/rte_common.h | 8 +++-
> > >  3 files changed, 9 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > > b/lib/librte_eal/common/eal_common_log.c
> > > index a27192620..36b9d6e08 100644
> > > --- a/lib/librte_eal/common/eal_common_log.c
> > > +++ b/lib/librte_eal/common/eal_common_log.c
> > > @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = {
> > >  };
> > >  
> > >  /* Logging should be first initializer (before drivers and bus) */
> > > -RTE_INIT_PRIO(rte_log_init, 101);
> > > +RTE_INIT_PRIO(rte_log_init, LOG);
> > >  static void
> > >  rte_log_init(void)
> > >  {
> > > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > > b/lib/librte_eal/common/include/rte_bus.h
> > > index 6fb08341a..eb9eded4e 100644
> > > --- a/lib/librte_eal/common/include/rte_bus.h
> > > +++ b/lib/librte_eal/common/include/rte_bus.h
> > > @@ -325,7 +325,7 @@ enum rte_iova_mode rte_bus_get_iommu_class(void);
> > >   * The constructor has higher priority than PMD constructors.
> > >   */
> > >  #define RTE_REGISTER_BUS(nm, bus) \
> > > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> > >  static void businitfn_ ##nm(void) \
> > >  {\
> > >   (bus).name = RTE_STR(nm);\
> > > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > > b/lib/librte_eal/common/include/rte_common.h
> > > index 6c5bc5a76..8f04518f7 100644
> > > --- a/lib/librte_eal/common/include/rte_common.h
> > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> > >   */
> > >  #define RTE_SET_USED(x) (void)(x)
> > >  
> > > +#define RTE_PRIORITY_LOG 101
> > > +#define RTE_PRIORITY_BUS 110
> > > +
> > > +#define RTE_PRIO(prio) \
> > > + RTE_PRIORITY_ ## prio
> > > +
> > >  /**
> > >   * Run function before main() with low priority.
> > >   *
> > > @@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) 
> > > func(void)
> > >   *   Lowest number is the first to run.
> > >   */
> > >  #define RTE_INIT_PRIO(func, prio) \
> > > -static void __attribute__((constructor(prio), used)) func(void)
> > > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
> > >  
> > It just occured to me, that perhaps you should add a RTE_PRORITY_LAST 
> > priority,
> > and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for 
> > clarity.  I
> > presume that constructors with no explicit priority run last, but the gcc
> > manual doesn't explicitly say that.  It would be a heck of a bug to track 
> > down
> > if somehow unprioritized constructors ran early.
> > 
> > Neil
> > 
> 
> While certainly poorly documented, the behavior is well-defined. I don't see
> a situation where the bug you describe could arise.
> 
> Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
> justified to add it. If you still think it is useful, I will do it.
> 
It was more just a way to unify the macros is all, probably not important.

> I'd be curious to hear if anyone has had issues of this kind.
> 
I've not had any, but I was suprised to see that the gcc manual didn't
explicitly call out the implied priority of unprioritized constructors

Neil

> -- 
> Gaëtan Rivet
> 6WIND
>

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-12 Thread Gaëtan Rivet 
Hello Neil,

On Thu, Apr 12, 2018 at 07:28:26AM -0400, Neil Horman wrote:
> On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> > Build a central list to quickly see each used priorities for
> > constructors, allowing to verify that they are both above 100 and in the
> > proper order.
> > 
> > Signed-off-by: Gaetan Rivet 
> > Acked-by: Neil Horman 
> > Acked-by: Shreyansh Jain 
> > ---
> >  lib/librte_eal/common/eal_common_log.c | 2 +-
> >  lib/librte_eal/common/include/rte_bus.h| 2 +-
> >  lib/librte_eal/common/include/rte_common.h | 8 +++-
> >  3 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/lib/librte_eal/common/eal_common_log.c 
> > b/lib/librte_eal/common/eal_common_log.c
> > index a27192620..36b9d6e08 100644
> > --- a/lib/librte_eal/common/eal_common_log.c
> > +++ b/lib/librte_eal/common/eal_common_log.c
> > @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = {
> >  };
> >  
> >  /* Logging should be first initializer (before drivers and bus) */
> > -RTE_INIT_PRIO(rte_log_init, 101);
> > +RTE_INIT_PRIO(rte_log_init, LOG);
> >  static void
> >  rte_log_init(void)
> >  {
> > diff --git a/lib/librte_eal/common/include/rte_bus.h 
> > b/lib/librte_eal/common/include/rte_bus.h
> > index 6fb08341a..eb9eded4e 100644
> > --- a/lib/librte_eal/common/include/rte_bus.h
> > +++ b/lib/librte_eal/common/include/rte_bus.h
> > @@ -325,7 +325,7 @@ enum rte_iova_mode rte_bus_get_iommu_class(void);
> >   * The constructor has higher priority than PMD constructors.
> >   */
> >  #define RTE_REGISTER_BUS(nm, bus) \
> > -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> > +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
> >  static void businitfn_ ##nm(void) \
> >  {\
> > (bus).name = RTE_STR(nm);\
> > diff --git a/lib/librte_eal/common/include/rte_common.h 
> > b/lib/librte_eal/common/include/rte_common.h
> > index 6c5bc5a76..8f04518f7 100644
> > --- a/lib/librte_eal/common/include/rte_common.h
> > +++ b/lib/librte_eal/common/include/rte_common.h
> > @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
> >   */
> >  #define RTE_SET_USED(x) (void)(x)
> >  
> > +#define RTE_PRIORITY_LOG 101
> > +#define RTE_PRIORITY_BUS 110
> > +
> > +#define RTE_PRIO(prio) \
> > +   RTE_PRIORITY_ ## prio
> > +
> >  /**
> >   * Run function before main() with low priority.
> >   *
> > @@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) 
> > func(void)
> >   *   Lowest number is the first to run.
> >   */
> >  #define RTE_INIT_PRIO(func, prio) \
> > -static void __attribute__((constructor(prio), used)) func(void)
> > +static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
> >  
> It just occured to me, that perhaps you should add a RTE_PRORITY_LAST 
> priority,
> and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for clarity.  
> I
> presume that constructors with no explicit priority run last, but the gcc
> manual doesn't explicitly say that.  It would be a heck of a bug to track down
> if somehow unprioritized constructors ran early.
> 
> Neil
> 

While certainly poorly documented, the behavior is well-defined. I don't see
a situation where the bug you describe could arise.

Adding RTE_PRIORITY_LAST is pretty harmless, but I'm not sure it's
justified to add it. If you still think it is useful, I will do it.

I'd be curious to hear if anyone has had issues of this kind.

-- 
Gaëtan Rivet
6WIND

Re: [dpdk-dev] [PATCH v5 02/21] eal: list acceptable init priorities

2018-04-12 Thread Neil Horman 
On Wed, Apr 11, 2018 at 02:04:03AM +0200, Gaetan Rivet wrote:
> Build a central list to quickly see each used priorities for
> constructors, allowing to verify that they are both above 100 and in the
> proper order.
> 
> Signed-off-by: Gaetan Rivet 
> Acked-by: Neil Horman 
> Acked-by: Shreyansh Jain 
> ---
>  lib/librte_eal/common/eal_common_log.c | 2 +-
>  lib/librte_eal/common/include/rte_bus.h| 2 +-
>  lib/librte_eal/common/include/rte_common.h | 8 +++-
>  3 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/librte_eal/common/eal_common_log.c 
> b/lib/librte_eal/common/eal_common_log.c
> index a27192620..36b9d6e08 100644
> --- a/lib/librte_eal/common/eal_common_log.c
> +++ b/lib/librte_eal/common/eal_common_log.c
> @@ -260,7 +260,7 @@ static const struct logtype logtype_strings[] = {
>  };
>  
>  /* Logging should be first initializer (before drivers and bus) */
> -RTE_INIT_PRIO(rte_log_init, 101);
> +RTE_INIT_PRIO(rte_log_init, LOG);
>  static void
>  rte_log_init(void)
>  {
> diff --git a/lib/librte_eal/common/include/rte_bus.h 
> b/lib/librte_eal/common/include/rte_bus.h
> index 6fb08341a..eb9eded4e 100644
> --- a/lib/librte_eal/common/include/rte_bus.h
> +++ b/lib/librte_eal/common/include/rte_bus.h
> @@ -325,7 +325,7 @@ enum rte_iova_mode rte_bus_get_iommu_class(void);
>   * The constructor has higher priority than PMD constructors.
>   */
>  #define RTE_REGISTER_BUS(nm, bus) \
> -RTE_INIT_PRIO(businitfn_ ##nm, 110); \
> +RTE_INIT_PRIO(businitfn_ ##nm, BUS); \
>  static void businitfn_ ##nm(void) \
>  {\
>   (bus).name = RTE_STR(nm);\
> diff --git a/lib/librte_eal/common/include/rte_common.h 
> b/lib/librte_eal/common/include/rte_common.h
> index 6c5bc5a76..8f04518f7 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -81,6 +81,12 @@ typedef uint16_t unaligned_uint16_t;
>   */
>  #define RTE_SET_USED(x) (void)(x)
>  
> +#define RTE_PRIORITY_LOG 101
> +#define RTE_PRIORITY_BUS 110
> +
> +#define RTE_PRIO(prio) \
> + RTE_PRIORITY_ ## prio
> +
>  /**
>   * Run function before main() with low priority.
>   *
> @@ -102,7 +108,7 @@ static void __attribute__((constructor, used)) func(void)
>   *   Lowest number is the first to run.
>   */
>  #define RTE_INIT_PRIO(func, prio) \
> -static void __attribute__((constructor(prio), used)) func(void)
> +static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
>  
It just occured to me, that perhaps you should add a RTE_PRORITY_LAST priority,
and redefine RTE_INIT to RTE_INIT_PRIO(func, RTE_PRIORITY_LAST) for clarity.  I
presume that constructors with no explicit priority run last, but the gcc
manual doesn't explicitly say that.  It would be a heck of a bug to track down
if somehow unprioritized constructors ran early.

Neil

>  /**
>   * Force a function to be inlined
> -- 
> 2.11.0
> 
>