Date: Fri, 28 Sep 2001 00:24:13 -0700 From: Julian Elischer <julian@elischer.org> To: arch@freebsd.org Subject: Re: KSE next steps... Message-ID: <3BB4259D.4AF78B4@elischer.org> References: <3BB410B3.A2527C09@elischer.org>
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> c) define the user interface so that userland code can start to be planned.
Here are some ideas..
these are up for discussion....
/* embed this in the Userland thread info */
struct kt_context {
struct kt_context *ktc_next_completed;
mcontext_t ktc_ctx;
void *ktc_UTS_private;
unsigned int ktc_return_info;
};
/* Need one of these per KSE. */
struct ks_mailbox {
struct kt_context *ksm_curthread;
struct kt_context *ksm_completed; /* runnable threads */
unsigned int ksm_upcall_reason;
/* probably some info for delivering signals */
}
possible syscalls....
int new_kse(struct ks_mailbox *mbox, int new_group); /* add a new KSE */
/* maybe in a new kse group */
int yield_kse(struct timespec *sleeptime); /* don't come back till */
/* time passed or work to do. */
int wake_kse(struct ks_mailbox *mbx); /* if we specify a yielded KSE *
/* both will return. NULL wakes any. */
void exit_kse(); /* Will not return, but */
/* writes completion code in mailbox. */
int abort_thread(struct kt_context *ktc); /* if we find a thread in */
/* this process that has this ktc, */
/* then if it is sleeping, abort the syscall */
/* if it is running, let it continue but set */
/* flag so that if it tries to sleep, it aborts */
/* instead */
maybe reversing the sycall names...
kse_new(), kse_yield(), kse_wake(), kse_exit(), thread_abort()
how to start a KSE....
do a setjmp()
Allocate a small stack.
put the jump buf address on it..
temporarily switch to that stack.
call a function that allocates the mailbox on that stack,
fill in fields needed.
call kse_new() with a pointer to the mailbox.
return to the old stack by doing the longjmp();
new KSE will also return from the kse_new(); so the small stack
must never be rewound... until after that thread calls kse_exit().
All upcalls will also return there...
kernel gets address of ktc from the mailbox. If the thread is
suspended, it will zero that field..
--
+------------------------------------+ ______ _ __
| __--_|\ Julian Elischer | \ U \/ / hard at work in
| / \ julian@elischer.org +------>x USA \ a very strange
| ( OZ ) \___ ___ | country !
+- X_.---._/ presently in San Francisco \_/ \\
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