CDA SC510 Podręcznik Użytkownika Pobierz pdf (Strona 12)

IST-033576 D2.1.4

• EIO: Problem writing the checkpoint output.

• ENOSPC: Out of space on ﬁlesystem while writing the check-

point

2.4.4 Callback

If the user wants some speciﬁc logic to be executed before the dump, BLCR pro-

vides a way to register user-level callback function triggered whenever a check-

point is about to occur, and which continue when a restart is initiated. Callbacks

are designed to be written in the following style :

vo i d m y_c a l l b a c k ( v oi d ∗ d a t a _ p t r )

{

s t r u c t my_data ∗ p d a t a =( s t r u c t my_data ∗)

d a t a _ p t r ;

/ / do c h e c k p o i n t −t i m e s hu t do wn l o g i c

/ / t e l l s y s t e m t o do t h e c h e c k p o i n t

d i d _ r e s t a r t = c r _ c h e c k p o i n t ( ) ;

i f ( d i d _ r e s t a r t )

/ / we ’ ve be en r e s t a r t e d fr o m a

c h e c k p o i n t

e l s e

/ / we ’ r e c o n t i n u i n g a f t e r t h e

c h e c k p o i n t

}

Following function must be used to register a callback :

c r _ r e g i s t e r _ c a l l b a c k ( c r _ c a l l b a c k _ t f unc , v oi d ∗ a rg ,

i n t f l a g s ) ;

Arguments are the following :

• func: pointer to a function taking a void* as its argument and returning an

int (it’s the callback function)

• arg: pointer which will be passed as argument to the callback when it will

be invoked

XtreemOS–Integrated Project 10/49

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CDA SC510 Podręcznik Użytkownika Strona 12