Optimize setrq() and remrq(). Implement swtch_xeit(p), which switches to
proc0's context, deallocates p's adress space, and resumes the swtch() that was suspended in proc0.
This commit is contained in:
mycroft
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b40fa7f850
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e6afef6b33
@ -1,3 +1,5 @@
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#undef DIAGNOSTIC
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#define DIAGNOSTIC
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/*-
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* Copyright (c) 1993, 1994 Charles Hannum.
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* Copyright (c) 1990 The Regents of the University of California.
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@ -35,7 +37,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
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* $Id: locore.s,v 1.54 1994/04/04 23:07:22 mycroft Exp $
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* $Id: locore.s,v 1.55 1994/04/05 07:59:55 mycroft Exp $
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*/
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/*
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@ -1313,23 +1315,26 @@ ENTRY(longjmp)
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*/
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ENTRY(setrq)
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movl 4(%esp),%eax
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#ifdef DIAGNOSTIC
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cmpl $0,P_RLINK(%eax) # should not be on q already
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jne 1f
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#endif
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movzbl P_PRI(%eax),%edx
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shrl $2,%edx
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btsl %edx,_whichqs # set q full bit
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shll $3,%edx
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addl $_qs,%edx # locate q hdr
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leal _qs(,%edx,8),%edx # locate q hdr
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movl %edx,P_LINK(%eax) # link process on tail of q
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movl P_RLINK(%edx),%ecx
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movl %ecx,P_RLINK(%eax)
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movl %eax,P_RLINK(%edx)
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movl %ecx,P_RLINK(%eax)
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movl %eax,P_LINK(%ecx)
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ret
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#ifdef DIAGNOSTIC
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1: pushl $2f
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call _panic
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/*NOTREACHED*/
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2: .asciz "setrq"
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#endif
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/*
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* Remrq(p)
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@ -1337,32 +1342,30 @@ ENTRY(setrq)
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* Call should be made at spl6().
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*/
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ENTRY(remrq)
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movl 4(%esp),%eax
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movzbl P_PRI(%eax),%edx
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shrl $2,%edx
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btrl %edx,_whichqs # clear full bit, panic if clear already
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jnb 1f
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pushl %edx
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movl P_LINK(%eax),%ecx # unlink process
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movl P_RLINK(%eax),%edx
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pushl %esi
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movl 8(%esp),%esi
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movzbl P_PRI(%esi),%eax
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shrl $2,%eax
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#ifdef DIAGNOSTIC
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btl %eax,_whichqs
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jnc 1f
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#endif
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movl P_LINK(%esi),%ecx # unlink process
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movl P_RLINK(%esi),%edx
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movl %edx,P_RLINK(%ecx)
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movl P_RLINK(%eax),%ecx
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movl P_LINK(%eax),%edx
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movl %edx,P_LINK(%ecx)
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popl %edx
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movl $_qs,%ecx
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shll $3,%edx
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addl %edx,%ecx
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cmpl P_LINK(%ecx),%ecx # q still has something?
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je 2f
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shrl $3,%edx # yes, set bit as still full
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btsl %edx,_whichqs
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2: movl $0,P_RLINK(%eax) # zap reverse link to indicate off list
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movl %ecx,P_LINK(%edx)
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movl $0,P_RLINK(%esi) # zap reverse link to indicate off list
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cmpl %edx,%ecx # q still has something?
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jne 2f
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btrl %eax,_whichqs # no; clear bit
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2: popl %esi
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ret
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#ifdef DIAGNOSTIC
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1: pushl $3f
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call _panic
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/*NOTREACHED*/
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3: .asciz "remrq"
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#endif
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/*
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* When no processes are on the runq, Swtch branches to idle
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@ -1405,6 +1408,7 @@ ENTRY(swtch)
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movl _curproc,%esi
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movl $0,_curproc
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swtch_search:
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/*
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* First phase: find new process.
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*
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@ -1562,23 +1566,50 @@ swtch_return:
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popl %ebx
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ret
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/*
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* struct proc *swtch_to_inactive(p) ; struct proc *p;
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*
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* At exit of a process, move off the address space of the
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* process and onto a "safe" one. Then, on a temporary stack
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* return and run code that disposes of the old state.
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* Since this code requires a parameter from the "old" stack,
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* pass it back as a return value.
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*/
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ENTRY(swtch_to_inactive)
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popl %edx # old pc
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popl %eax # arg, our return value
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movl _IdlePTD,%ecx
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movl %ecx,%cr3 # good bye address space
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#write buffer?
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movl $tmpstk-4,%esp # temporary stack, compensated for call
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jmp %edx # return, execute remainder of cleanup
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.globl _proc0, _vmspace_free, _kernel_map, _kmem_free
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ENTRY(swtch_exit)
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movl 4(%esp),%edi # old process
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movl $_proc0,%ebx
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incl _cnt+V_SWTCH
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/* Restore proc0's context. */
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cli
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movl P_ADDR(%ebx),%esi
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/* Switch address space. */
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movl PCB_CR3(%esi),%ecx
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movl %ecx,%cr3
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/* Don't need to worry about ldt. */
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/* Restore stack and segments. */
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movl PCB_ESP(%esi),%esp
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movl PCB_EBP(%esi),%ebp
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movl PCB_FS(%esi),%ecx # XXX necessary?
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movl %cx,%fs # XXX necessary?
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movl PCB_GS(%esi),%ecx # XXX necessary?
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movl %cx,%gs # XXX necessary?
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/* Record new pcb. */
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movl %esi,_curpcb
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/* Interrupts are okay again. */
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sti
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/* Thoroughly nuke the old process's resources. */
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pushl P_VMSPACE(%edi)
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call _vmspace_free
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pushl $(UPAGES << PGSHIFT)
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pushl P_ADDR(%edi)
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pushl _kernel_map
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call _kmem_free
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addl $16,%esp
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/* Jump into swtch() with the right state. */
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movl %ebx,%esi
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movl $0,_curproc
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jmp swtch_search
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/*
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* savectx(pcb, altreturn)
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