<div dir="ltr">Hi, all, I've updated this patch:<br>- rename freelist to freechain<br>- remove free_count<br>- replace freelist_bump() with an user defined extension handle<br>- add 2 test cases:<br> - spfreechain01: basic freechain operation test<br>
- spfreechain02: test whether freechain works correctly when calls user defined extension handle, and the handle uses malloc for memory allocation.<br><br>And I don't whether we need test case for user defined extension handle which uses workspace for memory allocation.<br>
<br>Thanks,<br>Zhongwei<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jul 12, 2013 at 6:57 PM, Ashi <span dir="ltr"><<a href="mailto:ashi08104@gmail.com" target="_blank">ashi08104@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><br><div class="gmail_quote"><div class="im">On Thu, Jul 11, 2013 at 9:18 PM, Gedare Bloom <span dir="ltr"><<a href="mailto:gedare@rtems.org" target="_blank">gedare@rtems.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I don't think we need SAPI. We could consider adding a "classic"<br>
manager interface. Meanwhile, you can write the testsuite with<br>
"#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__" and access the supercore<br>
freelist interface directly...<br></blockquote></div><div>OK, I'll use direct way for now. <br></div><div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div><br>
On Thu, Jul 11, 2013 at 12:25 AM, Ashi <<a href="mailto:ashi08104@gmail.com" target="_blank">ashi08104@gmail.com</a>> wrote:<br>
><br>
> And I'm adding the test case, and find we haven't the SAPI for freelist yet.<br>
> I must add it before adding test case, right? By the way, is the SAPI same<br>
> as the user-level API layer as Gedare mentioned before? I haven't realized<br>
> it before.<br>
><br>
><br>
> On Wed, Jul 10, 2013 at 8:31 PM, Gedare Bloom <<a href="mailto:gedare@rtems.org" target="_blank">gedare@rtems.org</a>> wrote:<br>
>><br>
>> You would call extend instead of calling bump, or as part of bumping.<br>
><br>
> Thanks, I see.<br>
>><br>
>><br>
>> On Wed, Jul 10, 2013 at 2:30 AM, Ashi <<a href="mailto:ashi08104@gmail.com" target="_blank">ashi08104@gmail.com</a>> wrote:<br>
>> > Thanks for all good explanation.<br>
>> ><br>
>> ><br>
>> > On Tue, Jul 9, 2013 at 11:24 PM, Sebastian Huber<br>
>> > <<a href="mailto:sebastian.huber@embedded-brains.de" target="_blank">sebastian.huber@embedded-brains.de</a>> wrote:<br>
>> >><br>
>> >> On 07/09/2013 05:29 AM, Ashi wrote:<br>
>> >>><br>
>> >>> Hi, Sebastian, thanks for your review!<br>
>> >>><br>
>> >>> 在 2013-7-7 下午9:49，"Sebastian Huber"<br>
>> >>> <<a href="mailto:sebastian.huber@embedded-brains.de" target="_blank">sebastian.huber@embedded-brains.de</a><br>
>> >>> <mailto:<a href="mailto:sebastian.huber@embedded-brains.de" target="_blank">sebastian.huber@embedded-brains.de</a>>>写道：<br>
>> >>><br>
>> >>> ><br>
>> >>> > Hello Ashi,<br>
>> >>> ><br>
>> >>> ><br>
>> >>> > On 06/07/13 09:17, Ashi wrote:<br>
>> >>> >><br>
>> >>> >> Hi all,<br>
>> >>> >><br>
>> >>> >> this patch adds a data structure called freelist to score, there<br>
>> >>> are<br>
>> >>> no<br>
>> >>> >> test cases yet and should be added later.<br>
>> >>> ><br>
>> >>> ><br>
>> >>> > I would appreciate to have the test for this new stuff included in<br>
>> >>> the<br>
>> >>> patch.<br>
>> >>><br>
>> >>><br>
>> >>> sure, I will update the patch with test cases.<br>
>> >>> ><br>
>> >>> ><br>
>> >>> >><br>
>> >>> >> Freelist is a structure, which contains a chain of nodes. It<br>
>> >>> supports<br>
>> >>> 2<br>
>> >>> >> operation:<br>
>> >>> >> - get node from freelist<br>
>> >>> >> - put node to freelist.<br>
>> >>> >> And when there is no enough node in freelist, it will<br>
>> >>> automatically<br>
>> >>> >> increase itself's size by allocate more nodes from heap or<br>
>> >>> workspace(which<br>
>> >>> >> is specified by user).<br>
>> >>> ><br>
>> >>> ><br>
>> >>> > What can I do if I like to get the nodes from a magic space?<br>
>> >>><br>
>> >>><br>
>> >>> sorry for the unclear, you can get nodes from freelist by 'get'<br>
>> >>> operation. And<br>
>> >>> if you mean get nodes from heap or workspace, it's done by<br>
>> >>> _Freelist_Get_node(), which calls _Freelist_Bump() when there is no<br>
>> >>> free<br>
>> >>> node left.<br>
>> >><br>
>> >><br>
>> >> Yes, the problem is that you limit your Freelist to the heap and<br>
>> >> workspace. If you use a handler function (or virtual method if you<br>
>> >> like)<br>
>> >> then you can avoid this limitation.<br>
>> >><br>
>> >> [...]<br>
>> >><br>
>> >>> >> +/**<br>
>> >>> >> + * @typedef freelist_callout<br>
>> >>> >> + */<br>
>> >>> >> +typedef void (*freelist_callout)(<br>
>> >>> >> + Freelist_Control *fc,<br>
>> >>> >> + void *nodes<br>
>> >>> >> +);<br>
>> >>> >> +<br>
>> >>> >> +/**<br>
>> >>> >> + * @typedef Freelist_Control_struct<br>
>> >>> >> + *<br>
>> >>> >> + * This is used to manage each element.<br>
>> >>> >> + */<br>
>> >>> >> +struct Freelist_Control_struct {<br>
>> >>> >> + Chain_Control Freelist;<br>
>> >>> >> + size_t free_count;<br>
>> >>> ><br>
>> >>> ><br>
>> >>> > Why do we need the free_count?<br>
>> >>><br>
>> >>> free_count is used to keep track how many nodes there is in freelist.<br>
>> >>> And<br>
>> >>> if<br>
>> >>> free_count is 0 when you try to get node from freelist by call<br>
>> >>> _Freelist_Get_node(), _Freelist_Get_node() will call _Freelist_Bump()<br>
>> >>> to<br>
>> >>> allocate more node from heap or workspace.<br>
>> >><br>
>> >><br>
>> >> The list knows if it is empty. There is not need to store this<br>
>> >> information in two ways.<br>
>> >><br>
>> >><br>
>> >>> ><br>
>> >>> >> + size_t bump_count;<br>
>> >>> >> + size_t node_size;<br>
>> >>> ><br>
>> >>> ><br>
>> >>> >> + freelist_callout callout;<br>
>> >>> >> + bool use_workspace;<br>
>> >>> >> +};<br>
>> >>> ><br>
>> >>> ><br>
>> >>> > I would replace this with an extend handler.<br>
>> >>> ><br>
>> >>> > /**<br>
>> >>> > * @brief Extends the freelist.<br>
>> >>> > *<br>
>> >>> > * @param[in] freelist The freelist control.<br>
>> >>> > *<br>
>> >>> > * @return The count of new nodes.<br>
>> >>> > */<br>
>> >>> > typedef size_t ( *Freelist_Extend )( Freelist_Control *freelist );<br>
>> >>> ><br>
>> >>> > This is much more flexible since you only specify the interface and<br>
>> >>> don't<br>
>> >>> limit this to heap/workspace.<br>
>> >>> ><br>
>> >>> > You can provide a _Freelist_Extend_with_nothing() which simply<br>
>> >>> returns<br>
>> >>> 0.<br>
>> >>><br>
>> >>> Yeah, this Freelist_Extend is very flexible, but I feel the<br>
>> >>> Freelist_Extend is<br>
>> >>> a little complex. As it shows in _Freelist_Bump(), if users provides<br>
>> >>> their own<br>
>> >>> extension function, they have to append there new nodes to freelist's<br>
>> >>> internal<br>
>> >>> chain and call their callout function on new nodes. And since<br>
>> >>> _Freelist_Initialize() also would call Freelist_Extend(), if we<br>
>> >>> provided<br>
>> >>> _Freelist_Extend_with_nothing(), the initialization may fail.<br>
>> >><br>
>> >><br>
>> >> Since the Freelist_Extend gets the Freelist as a first argument it can<br>
>> >> set<br>
>> >> the extend handler to _Freelist_Extend_with_nothing() after the first<br>
>> >> invocation.<br>
>> >><br>
>> >> Example:<br>
>> >><br>
>> >><br>
>> >> /**<br>
>> >> * @brief Extends the freelist.<br>
>> >> *<br>
>> >> * @param[in] freelist The freelist control.<br>
>> >> */<br>
>> >> typedef void ( *Freelist_Extend )( Freelist_Control *freelist );<br>
>> >><br>
>> >> typedef struct {<br>
>> >> Objects_Control obj;<br>
>> >> int x;<br>
>> >> } my_obj;<br>
>> >><br>
>> >> void my_extend( Freelist_Control *freelist )<br>
>> >> {<br>
>> >> size_t bump_count = freelist->bump_count;<br>
>> >> size_t size = bump_count * sizeof(my_obj);<br>
>> >> my_obj *objs = malloc(size);<br>
>> >><br>
>> >> _Freelist_Set_extend_handler( freelist, _Freelist_Extend_with_nothing<br>
>> >> );<br>
>> >> _Chain_Initialize(<br>
>> >> _Freelist_Get_list( freelist ),<br>
>> >> objs,<br>
>> >> bump_count,<br>
>> >> size<br>
>> >> );<br>
>> >><br>
>> >> }<br>
>> ><br>
>> > I'm a little confused by my_extend() function, is it only called after<br>
>> > calling _Freelist_Initialize() by user?<br>
>> >><br>
>> >><br>
>> >> [...]<br>
>> >><br>
>> >> --<br>
>> >> Sebastian Huber, embedded brains GmbH<br>
>> >><br>
>> >> Address : Dornierstr. 4, D-82178 Puchheim, Germany<br>
>> >> Phone : +49 89 189 47 41-16<br>
>> >> Fax : +49 89 189 47 41-09<br>
>> >> E-Mail : <a href="mailto:sebastian.huber@embedded-brains.de" target="_blank">sebastian.huber@embedded-brains.de</a><br>
>> >> PGP : Public key available on request.<br>
>> >><br>
>> >> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.<br>
>> ><br>
>> ><br>
>> > Cheers,<br>
>> > Zhongwei<br>
>> ><br>
><br>
><br>
</div></div></blockquote></div></div></div><br></div></div>
</blockquote></div><br></div>