From owner-freebsd-current Fri Oct 4 6:41:51 2002 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 58B3D37B401 for ; Fri, 4 Oct 2002 06:41:44 -0700 (PDT) Received: from fafoe.dyndns.org (chello212186121237.14.vie.surfer.at [212.186.121.237]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3D08343E7B for ; Fri, 4 Oct 2002 06:41:43 -0700 (PDT) (envelope-from stefan@fafoe.dyndns.org) Received: by frog.fafoe (Postfix, from userid 1001) id 0E3771E3; Fri, 4 Oct 2002 15:41:42 +0200 (CEST) Date: Fri, 4 Oct 2002 15:41:41 +0200 From: Stefan Farfeleder To: Poul-Henning Kamp Cc: current@FreeBSD.ORG Subject: Re: Junior Kernel Hacker page updated... Message-ID: <20021004134141.GA263@frog.fafoe> References: <20021002214028.GA94673@frog.fafoe> <4860.1033656106@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="NMuMz9nt05w80d4+" Content-Disposition: inline In-Reply-To: <4860.1033656106@critter.freebsd.dk> User-Agent: Mutt/1.5.1i Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG --NMuMz9nt05w80d4+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Oct 03, 2002 at 04:41:46PM +0200, Poul-Henning Kamp wrote: > > Hi Stefan, > > I tried this patch and it paniced my (almost-) current machine with > a pagefault in the kqueue code: Bravo! > > I can see that there is some amount of #ifdef stuff in your patch, The #ifdefs are already in the code, namely REMOTE and RMT_WILL_WATCH. Is anybody using them? Building with -DREMOTE doesn't compile and with -DRMT_WILL_WATCH the linker is complaining about the lack of the functions Rmt_Ignore(), Rmt_Watch() and Rmt_Wait(). Can't we get rid of those defines? I understand Juli Mallett wants to rewrite make, so maybe this effort would be wasted. > in light of that, would it be possible to make an #ifdef'ed version > of your patch which we could commit ? Ok, the new patch is attached. Compile with -DUSE_KQUEUE to use the new code. > That way we give the kqueue hackers a good testcase, and we can > easily enable when they have solved the problem. After Don Lewis fixed the 'could sleep with' problem (thanks!), I'm still encountering freezes and panics. Here's one I caught: [warning: parts are typed in] %%% Fatal trap 12: page fault while in kernel mode cpuid = 0; lapic.id = 00000000 fault virtual address = 0x8 fault code = supervisor read, page not present instruction pointer = 0x8:0xc01a1212 stack pointer = 0x10:0xe5226c14 frame pointer = 0x10:0xe5226ca0 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, def32 1, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 56525 (make) kernel: type 12 trap, code = 0 Stopped at kqueue_scan+0x242: cmpl $0,0x8(%ebx) db> trace kqueue_scan(c6472bf4,4,bfbfebc0,0,c70ecea0) at kqueue_scan+0x242 kevent(c70ecea0,e5226d10,c0351d80,418,6) at kevent+0x1e1 syscall(2f,2f,2f,818d780,818d960) at syscall+0x2be %%% The core file doesn't seem to be particularly helpful, as the kqueue_scan frame seems to miss: %%% (kgdb) bt #0 doadump () at /freebsd/current/src/sys/kern/kern_shutdown.c:223 #1 0xc01ba92a in boot (howto=260) at /freebsd/current/src/sys/kern/kern_shutdown.c:355 #2 0xc01babe7 in panic () at /freebsd/current/src/sys/kern/kern_shutdown.c:508 #3 0xc013b1d2 in db_panic () at /freebsd/current/src/sys/ddb/db_command.c:450 #4 0xc013b152 in db_command (last_cmdp=0xc035db20, cmd_table=0x0, aux_cmd_tablep=0xc03577dc, aux_cmd_tablep_end=0xc03577e0) at /freebsd/current/src/sys/ddb/db_command.c:346 #5 0xc013b266 in db_command_loop () at /freebsd/current/src/sys/ddb/db_command.c:472 #6 0xc013deca in db_trap (type=12, code=0) at /freebsd/current/src/sys/ddb/db_trap.c:72 #7 0xc02e9f60 in kdb_trap (type=12, code=0, regs=0xe5226bd4) at /freebsd/current/src/sys/i386/i386/db_interface.c:166 #8 0xc0302602 in trap_fatal (frame=0xe5226bd4, eva=0) at /freebsd/current/src/sys/i386/i386/trap.c:841 #9 0xc03022e2 in trap_pfault (frame=0xe5226bd4, usermode=0, eva=8) at /freebsd/current/src/sys/i386/i386/trap.c:760 #10 0xc0301e0d in trap (frame= {tf_fs = 24, tf_es = 16, tf_ds = 16, tf_edi = -943606528, tf_esi = -943606488, tf_ebp = -450728800, tf_isp = -450728960, tf_ebx = 0, tf_edx = 4, tf_ecx = 1, tf_eax = 0, tf_trapno = 12, tf_err = 0, tf_eip = -1072033262, tf_cs = 8, tf_eflags = 66050, tf_esp = -966356416, tf_ss = 0}) ---Type to continue, or q to quit--- at /freebsd/current/src/sys/i386/i386/trap.c:446 #11 0xc02eb768 in calltrap () at {standard input}:99 #12 0xc01a0ad1 in kevent (td=0xc70ecea0, uap=0xe5226d10) at /freebsd/current/src/sys/kern/kern_event.c:470 #13 0xc030299e in syscall (frame= {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 135845760, tf_esi = 135846240, tf_ebp = -1077941224, tf_isp = -450728588, tf_ebx = 134831872, tf_edx = 2184, tf_ecx = 0, tf_eax = 363, tf_trapno = 12, tf_err = 2, tf_eip = 134626551, tf_cs = 31, tf_eflags = 514, tf_esp = -1077941348, tf_ss = 47}) at /freebsd/current/src/sys/i386/i386/trap.c:1050 #14 0xc02eb7bd in Xint0x80_syscall () at {standard input}:141 ---Can't read userspace from dump, or kernel process--- %%% objdump -dS kern_event.o says the following about kqueue_scan+0x242 [==0xfd2]: %%% fce: 90 nop fcf: 90 nop kn = TAILQ_FIRST(&kq->kq_head); fd0: 8b 1f mov (%edi),%ebx TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); fd2: 83 7b 08 00 cmpl $0x0,0x8(%ebx) fd6: 74 0b je fe3 fd8: 8b 53 08 mov 0x8(%ebx),%edx fdb: 8b 43 0c mov 0xc(%ebx),%eax fde: 89 42 0c mov %eax,0xc(%edx) fe1: eb 06 jmp fe9 fe3: 8b 43 0c mov 0xc(%ebx),%eax fe6: 89 47 04 mov %eax,0x4(%edi) fe9: 8b 43 0c mov 0xc(%ebx),%eax fec: 8b 53 08 mov 0x8(%ebx),%edx fef: 89 10 mov %edx,(%eax) if (kn == &marker) { ff1: 8d 45 b4 lea 0xffffffb4(%ebp),%eax ff4: 39 c3 cmp %eax,%ebx ff6: 75 18 jne 1010 splx(s); [...] %%% This seems to indicate that TAILQ_FIRST returns a null pointer and TAILQ_REMOVE tries to dereference it, doesn't it? Maybe 'count' is not 0 though it should be? Regards, Stefan Farfeleder --NMuMz9nt05w80d4+ Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="make-cond.diff" Index: job.c =================================================================== RCS file: /home/ncvs/src/usr.bin/make/job.c,v retrieving revision 1.43 diff -u -r1.43 job.c --- job.c 29 Sep 2002 00:20:28 -0000 1.43 +++ job.c 4 Oct 2002 10:58:52 -0000 @@ -106,6 +106,7 @@ #include #include #include +#include #include #include #include @@ -237,9 +238,13 @@ * (2) a job can only be run locally, but * nLocal equals maxLocal */ #ifndef RMT_WILL_WATCH +#ifdef USE_KQUEUE +static int kqfd; /* File descriptor obtained by kqueue() */ +#else static fd_set outputs; /* Set of descriptors of pipes connected to * the output channels of children */ #endif +#endif STATIC GNode *lastNode; /* The node for which output was most recently * produced. */ @@ -692,7 +697,7 @@ if (usePipes) { #ifdef RMT_WILL_WATCH Rmt_Ignore(job->inPipe); -#else +#elif !defined(USE_KQUEUE) FD_CLR(job->inPipe, &outputs); #endif if (job->outPipe != job->inPipe) { @@ -1267,10 +1272,22 @@ * position in the buffer to the beginning and mark another * stream to watch in the outputs mask */ +#ifdef USE_KQUEUE + struct kevent kev[2]; +#endif job->curPos = 0; #ifdef RMT_WILL_WATCH Rmt_Watch(job->inPipe, JobLocalInput, job); +#elif defined(USE_KQUEUE) + EV_SET(&kev[0], job->inPipe, EVFILT_READ, EV_ADD, 0, 0, job); + EV_SET(&kev[1], job->pid, EVFILT_PROC, EV_ADD | EV_ONESHOT, + NOTE_EXIT, 0, NULL); + if (kevent(kqfd, kev, 2, NULL, 0, NULL) != 0) { + /* kevent() will fail if the job is already finished */ + if (errno != EBADF && errno != ESRCH) + Punt("kevent: %s", strerror(errno)); + } #else FD_SET(job->inPipe, &outputs); #endif /* RMT_WILL_WATCH */ @@ -2229,10 +2246,16 @@ Job_CatchOutput() { int nfds; +#ifdef USE_KQUEUE +#define KEV_SIZE 4 + struct kevent kev[KEV_SIZE]; + int i; +#else struct timeval timeout; fd_set readfds; LstNode ln; Job *job; +#endif #ifdef RMT_WILL_WATCH int pnJobs; /* Previous nJobs */ #endif @@ -2262,6 +2285,27 @@ } #else if (usePipes) { +#ifdef USE_KQUEUE + if ((nfds = kevent(kqfd, NULL, 0, kev, KEV_SIZE, NULL)) == -1) { + Punt("kevent: %s", strerror(errno)); + } else { + for (i = 0; i < nfds; i++) { + if (kev[i].flags & EV_ERROR) { + warnc(kev[i].data, "kevent"); + continue; + } + switch (kev[i].filter) { + case EVFILT_READ: + JobDoOutput(kev[i].udata, FALSE); + break; + case EVFILT_PROC: + /* Just wake up and let Job_CatchChildren() collect the + * terminated job. */ + break; + } + } + } +#else readfds = outputs; timeout.tv_sec = SEL_SEC; timeout.tv_usec = SEL_USEC; @@ -2282,6 +2326,7 @@ } Lst_Close(jobs); } +#endif /* !USE_KQUEUE */ } #endif /* RMT_WILL_WATCH */ } @@ -2408,6 +2453,12 @@ } if (signal(SIGWINCH, SIG_IGN) != SIG_IGN) { (void) signal(SIGWINCH, JobPassSig); + } +#endif + +#ifdef USE_KQUEUE + if ((kqfd = kqueue()) == -1) { + Punt("kqueue: %s", strerror(errno)); } #endif Index: job.h =================================================================== RCS file: /home/ncvs/src/usr.bin/make/job.h,v retrieving revision 1.18 diff -u -r1.18 job.h --- job.h 26 Sep 2002 01:39:22 -0000 1.18 +++ job.h 4 Oct 2002 10:55:11 -0000 @@ -50,6 +50,7 @@ #define TMPPAT "/tmp/makeXXXXXXXXXX" +#ifndef USE_KQUEUE /* * The SEL_ constants determine the maximum amount of time spent in select * before coming out to see if a child has finished. SEL_SEC is the number of @@ -57,6 +58,7 @@ */ #define SEL_SEC 0 #define SEL_USEC 100000 +#endif /* !USE_KQUEUE */ /*- --NMuMz9nt05w80d4+-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message