On Thu, Jul 11, 2013 at 9:18 PM, Gedare Bloom <ged...@rtems.org> wrote:
> I don't think we need SAPI. We could consider adding a "classic" > manager interface. Meanwhile, you can write the testsuite with > "#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__" and access the supercore > freelist interface directly... > OK, I'll use direct way for now. > > On Thu, Jul 11, 2013 at 12:25 AM, Ashi <ashi08...@gmail.com> wrote: > > > > And I'm adding the test case, and find we haven't the SAPI for freelist > yet. > > I must add it before adding test case, right? By the way, is the SAPI > same > > as the user-level API layer as Gedare mentioned before? I haven't > realized > > it before. > > > > > > On Wed, Jul 10, 2013 at 8:31 PM, Gedare Bloom <ged...@rtems.org> wrote: > >> > >> You would call extend instead of calling bump, or as part of bumping. > > > > Thanks, I see. > >> > >> > >> On Wed, Jul 10, 2013 at 2:30 AM, Ashi <ashi08...@gmail.com> wrote: > >> > Thanks for all good explanation. > >> > > >> > > >> > On Tue, Jul 9, 2013 at 11:24 PM, Sebastian Huber > >> > <sebastian.hu...@embedded-brains.de> wrote: > >> >> > >> >> On 07/09/2013 05:29 AM, Ashi wrote: > >> >>> > >> >>> Hi, Sebastian, thanks for your review! > >> >>> > >> >>> 在 2013-7-7 下午9:49，"Sebastian Huber" > >> >>> <sebastian.hu...@embedded-brains.de > >> >>> <mailto:sebastian.hu...@embedded-brains.de>>写道： > >> >>> > >> >>> > > >> >>> > Hello Ashi, > >> >>> > > >> >>> > > >> >>> > On 06/07/13 09:17, Ashi wrote: > >> >>> >> > >> >>> >> Hi all, > >> >>> >> > >> >>> >> this patch adds a data structure called freelist to score, there > >> >>> are > >> >>> no > >> >>> >> test cases yet and should be added later. > >> >>> > > >> >>> > > >> >>> > I would appreciate to have the test for this new stuff included > in > >> >>> the > >> >>> patch. > >> >>> > >> >>> > >> >>> sure, I will update the patch with test cases. > >> >>> > > >> >>> > > >> >>> >> > >> >>> >> Freelist is a structure, which contains a chain of nodes. It > >> >>> supports > >> >>> 2 > >> >>> >> operation: > >> >>> >> - get node from freelist > >> >>> >> - put node to freelist. > >> >>> >> And when there is no enough node in freelist, it will > >> >>> automatically > >> >>> >> increase itself's size by allocate more nodes from heap or > >> >>> workspace(which > >> >>> >> is specified by user). > >> >>> > > >> >>> > > >> >>> > What can I do if I like to get the nodes from a magic space? > >> >>> > >> >>> > >> >>> sorry for the unclear, you can get nodes from freelist by 'get' > >> >>> operation. And > >> >>> if you mean get nodes from heap or workspace, it's done by > >> >>> _Freelist_Get_node(), which calls _Freelist_Bump() when there is no > >> >>> free > >> >>> node left. > >> >> > >> >> > >> >> Yes, the problem is that you limit your Freelist to the heap and > >> >> workspace. If you use a handler function (or virtual method if you > >> >> like) > >> >> then you can avoid this limitation. > >> >> > >> >> [...] > >> >> > >> >>> >> +/** > >> >>> >> + * @typedef freelist_callout > >> >>> >> + */ > >> >>> >> +typedef void (*freelist_callout)( > >> >>> >> + Freelist_Control *fc, > >> >>> >> + void *nodes > >> >>> >> +); > >> >>> >> + > >> >>> >> +/** > >> >>> >> + * @typedef Freelist_Control_struct > >> >>> >> + * > >> >>> >> + * This is used to manage each element. > >> >>> >> + */ > >> >>> >> +struct Freelist_Control_struct { > >> >>> >> + Chain_Control Freelist; > >> >>> >> + size_t free_count; > >> >>> > > >> >>> > > >> >>> > Why do we need the free_count? > >> >>> > >> >>> free_count is used to keep track how many nodes there is in > freelist. > >> >>> And > >> >>> if > >> >>> free_count is 0 when you try to get node from freelist by call > >> >>> _Freelist_Get_node(), _Freelist_Get_node() will call > _Freelist_Bump() > >> >>> to > >> >>> allocate more node from heap or workspace. > >> >> > >> >> > >> >> The list knows if it is empty. There is not need to store this > >> >> information in two ways. > >> >> > >> >> > >> >>> > > >> >>> >> + size_t bump_count; > >> >>> >> + size_t node_size; > >> >>> > > >> >>> > > >> >>> >> + freelist_callout callout; > >> >>> >> + bool use_workspace; > >> >>> >> +}; > >> >>> > > >> >>> > > >> >>> > I would replace this with an extend handler. > >> >>> > > >> >>> > /** > >> >>> > * @brief Extends the freelist. > >> >>> > * > >> >>> > * @param[in] freelist The freelist control. > >> >>> > * > >> >>> > * @return The count of new nodes. > >> >>> > */ > >> >>> > typedef size_t ( *Freelist_Extend )( Freelist_Control *freelist > ); > >> >>> > > >> >>> > This is much more flexible since you only specify the interface > and > >> >>> don't > >> >>> limit this to heap/workspace. > >> >>> > > >> >>> > You can provide a _Freelist_Extend_with_nothing() which simply > >> >>> returns > >> >>> 0. > >> >>> > >> >>> Yeah, this Freelist_Extend is very flexible, but I feel the > >> >>> Freelist_Extend is > >> >>> a little complex. As it shows in _Freelist_Bump(), if users provides > >> >>> their own > >> >>> extension function, they have to append there new nodes to > freelist's > >> >>> internal > >> >>> chain and call their callout function on new nodes. And since > >> >>> _Freelist_Initialize() also would call Freelist_Extend(), if we > >> >>> provided > >> >>> _Freelist_Extend_with_nothing(), the initialization may fail. > >> >> > >> >> > >> >> Since the Freelist_Extend gets the Freelist as a first argument it > can > >> >> set > >> >> the extend handler to _Freelist_Extend_with_nothing() after the first > >> >> invocation. > >> >> > >> >> Example: > >> >> > >> >> > >> >> /** > >> >> * @brief Extends the freelist. > >> >> * > >> >> * @param[in] freelist The freelist control. > >> >> */ > >> >> typedef void ( *Freelist_Extend )( Freelist_Control *freelist ); > >> >> > >> >> typedef struct { > >> >> Objects_Control obj; > >> >> int x; > >> >> } my_obj; > >> >> > >> >> void my_extend( Freelist_Control *freelist ) > >> >> { > >> >> size_t bump_count = freelist->bump_count; > >> >> size_t size = bump_count * sizeof(my_obj); > >> >> my_obj *objs = malloc(size); > >> >> > >> >> _Freelist_Set_extend_handler( freelist, > _Freelist_Extend_with_nothing > >> >> ); > >> >> _Chain_Initialize( > >> >> _Freelist_Get_list( freelist ), > >> >> objs, > >> >> bump_count, > >> >> size > >> >> ); > >> >> > >> >> } > >> > > >> > I'm a little confused by my_extend() function, is it only called after > >> > calling _Freelist_Initialize() by user? > >> >> > >> >> > >> >> [...] > >> >> > >> >> -- > >> >> Sebastian Huber, embedded brains GmbH > >> >> > >> >> Address : Dornierstr. 4, D-82178 Puchheim, Germany > >> >> Phone : +49 89 189 47 41-16 > >> >> Fax : +49 89 189 47 41-09 > >> >> E-Mail : sebastian.hu...@embedded-brains.de > >> >> PGP : Public key available on request. > >> >> > >> >> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG. > >> > > >> > > >> > Cheers, > >> > Zhongwei > >> > > > > > >
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