線程的狀態(tài)和轉(zhuǎn)換

實(shí)驗(yàn)線程的狀態(tài)和轉(zhuǎn)換實(shí)驗(yàn)?zāi)康恼{(diào)試線程在各種狀態(tài)間的轉(zhuǎn)換過程，熟悉線程的狀態(tài)和轉(zhuǎn)換。通過為線程增加掛起狀態(tài)，加深對(duì)線程狀態(tài)的理解。線程的狀態(tài)和其轉(zhuǎn)換過程線程控制塊中的狀態(tài)域

及線程狀態(tài)的枚舉定義typedef struct_THREAD{ ……

UCHARState;

//線程當(dāng)前狀態(tài) ……

}THREAD;typedefenum_THREAD_STATE{ Zero, //線程狀態(tài)轉(zhuǎn)換過程中的中間狀態(tài) Ready, //就緒 Running, //運(yùn)行 Waiting, //等待（阻塞） Terminated //結(jié)束}THREAD_STATE;線程處于運(yùn)行、就緒、阻塞狀態(tài)時(shí)

線程控制塊的位置線程控制塊都是從系統(tǒng)內(nèi)存池中分配的！運(yùn)行狀態(tài)：全局變量PspCurrentThread指向處于運(yùn)行狀態(tài)線程的線程控制塊。就緒狀態(tài)：線程控制塊在其優(yōu)先級(jí)對(duì)應(yīng)的就緒隊(duì)列中。阻塞狀態(tài)：線程控制塊在同步對(duì)象的等待隊(duì)列中。線程狀態(tài)轉(zhuǎn)換包括：線程控制塊中狀態(tài)域的變化，線程控制塊位置的變化等。線程由阻塞狀態(tài)進(jìn)入就緒狀態(tài)的源代碼PTHREAD

PspWakeThread(

INPLIST_ENTRYWaitListHead,

INSTATUSWaitStatus

)

{

PTHREADThread; if(!ListIsEmpty(WaitListHead)){

Thread=CONTAINING_RECORD(WaitListHead->Next,THREAD,StateListEntry);

PspUnwaitThread(Thread);

PspReadyThread(Thread);

Thread->WaitStatus=WaitStatus; }else{ Thread=NULL;

} returnThread;

}VOIDPspUnwaitThread( INPTHREADThread ){ ASSERT(Waiting==Thread->State); ListRemoveEntry(&Thread->StateListEntry); Thread->State=Zero; if(STATUS_TIMEOUT==Thread->WaitStatus){ KeUnregisterTimer(&Thread->WaitTimer); }}VOIDPspReadyThread( PTHREADThread ){ ASSERT(NULL!=Thread); ASSERT(Zero==Thread->State||Running==Thread->State); // //將線程插入其優(yōu)先級(jí)對(duì)應(yīng)的就緒隊(duì)列的隊(duì)尾，并設(shè)置就緒位圖中對(duì)應(yīng)的位。

//最后將線程的狀態(tài)修改為就緒狀態(tài)。

// ListInsertTail(&PspReadyListHeads[Thread->Priority],&Thread->StateListEntry); BIT_SET(PspReadyBitmap,Thread->Priority); Thread->State=Ready;}線程由運(yùn)行狀態(tài)進(jìn)入就緒狀態(tài)的源代碼PCONTEXTPspSelectNextThread( VOID ){ …… if(NULL!=PspCurrentThread&&Running==PspCurrentThread->State){ if(0!=PspReadyBitmap&&HighestPriority>PspCurrentThread->Priority){ ListInsertHead(&PspReadyListHeads[PspCurrentThread->Priority], &PspCurrentThread->StateListEntry); BIT_SET(PspReadyBitmap,PspCurrentThread->Priority); PspCurrentThread->State=Ready; } …… } ……}線程由就緒狀態(tài)進(jìn)入運(yùn)行狀態(tài)的源代碼PCONTEXTPspSelectNextThread( VOID ){ …… PspCurrentThread=CONTAINING_RECORD(PspReadyListHeads[HighestPriority].Next, THREAD,StateListEntry); ObRefObject(PspCurrentThread);

PspUnreadyThread(PspCurrentThread); PspCurrentThread->State=Running; ……}VOIDPspUnreadyThread( PTHREADThread ){ ASSERT(NULL!=Thread&&Ready==Thread->State); ListRemoveEntry(&Thread->StateListEntry); if(ListIsEmpty(&PspReadyListHeads[Thread->Priority])){ BIT_CLEAR(PspReadyBitmap,Thread->Priority); } Thread->State=Zero;}線程由運(yùn)行狀態(tài)進(jìn)入阻塞狀態(tài)的源代碼STATUSPspWait( INPLIST_ENTRYWaitListHead, INULONGMilliseconds ){ …… ListInsertTail(WaitListHead,&PspCurrentThread->StateListEntry); PspCurrentThread->State=Waiting; //當(dāng)前線程進(jìn)入等待狀態(tài)后需要讓出處理器（讓權(quán)等待），執(zhí)行線程調(diào)度。 PspThreadSchedule();

//zzZ... ……}為線程增加掛起狀態(tài)命令：suspendThreadID和resumeThreadIDAPI函數(shù)：SuspendThread和ResumeThread內(nèi)核函數(shù)：PsSuspendThread和PsResumeThread掛起線程的源代碼LIST_ENTRYSuspendListHead={&SuspendListHead,&SuspendListHead};STATUSPsSuspendThread(INHANDLEhThread){ STATUSStatus; BOOLIntState; PTHREADThread; Status=ObRefObjectByHandle(hThread,PspThreadType,(PVOID*)&Thread); if(EOS_SUCCESS(Status)){ IntState=KeEnableInterrupts(FALSE); //關(guān)中斷

if(Ready==Thread->State){ PspUnreadyThread(Thread); ListInsertTail(&SuspendListHead,&Thread->StateListEntry); Status=STATUS_SUCCESS; }else{ Status=STATUS_NOT_SUPPORTED; } KeEnableInterrupts(IntState); //開中斷

ObDerefObject(Thread); } returnStatus;}恢復(fù)線程的源代碼STATUSPsResumThread(INHANDLEhThread){ STATUSStatus; BOOLIntState; PTHREADThread; Status=ObRefObjectByHandle(hThread,PspThreadType,(PVOID*)&Thread); if(EOS_SUCCESS(Status)){ IntState=KeEnableInterrupts(FALSE); //關(guān)中斷

if(Zero==Thread->State){