Date: Fri, 2 Sep 2005 19:39:34 GMT From: John Baldwin <jhb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 83036 for review Message-ID: <200509021939.j82JdYgP074208@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=83036 Change 83036 by jhb@jhb_slimer on 2005/09/02 19:39:25 Add a simple API to indicate that a thread is not allowed to sleep and use it in place of the g_xdown and g_xup mutexes. Also, use it in the ithreads around the handlers. Also, add a test for it to the crash module. Affected files ... .. //depot/projects/smpng/sys/geom/geom_io.c#37 edit .. //depot/projects/smpng/sys/kern/kern_intr.c#69 edit .. //depot/projects/smpng/sys/kern/subr_sleepqueue.c#17 edit .. //depot/projects/smpng/sys/modules/crash/crash.c#17 edit .. //depot/projects/smpng/sys/notes#53 edit .. //depot/projects/smpng/sys/sys/proc.h#148 edit Differences ... ==== //depot/projects/smpng/sys/geom/geom_io.c#37 (text+ko) ==== @@ -42,6 +42,7 @@ #include <sys/malloc.h> #include <sys/bio.h> #include <sys/ktr.h> +#include <sys/proc.h> #include <sys/errno.h> #include <geom/geom.h> @@ -364,12 +365,6 @@ struct bio *bp; off_t excess; int error; -#ifdef WITNESS - struct mtx mymutex; - - bzero(&mymutex, sizeof mymutex); - mtx_init(&mymutex, "g_xdown", NULL, MTX_DEF); -#endif for(;;) { g_bioq_lock(&g_bio_run_down); @@ -425,16 +420,12 @@ default: break; } -#ifdef WITNESS - mtx_lock(&mymutex); -#endif + THREAD_NO_SLEEPING(); CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld " "len %ld", bp, bp->bio_to->name, bp->bio_offset, bp->bio_length); bp->bio_to->geom->start(bp); -#ifdef WITNESS - mtx_unlock(&mymutex); -#endif + THREAD_SLEEPING_OK(); } } @@ -462,40 +453,26 @@ g_io_schedule_up(struct thread *tp __unused) { struct bio *bp; -#ifdef WITNESS - struct mtx mymutex; - - bzero(&mymutex, sizeof mymutex); - mtx_init(&mymutex, "g_xup", NULL, MTX_DEF); -#endif for(;;) { g_bioq_lock(&g_bio_run_up); bp = g_bioq_first(&g_bio_run_task); if (bp != NULL) { g_bioq_unlock(&g_bio_run_up); -#ifdef WITNESS - mtx_lock(&mymutex); -#endif + THREAD_NO_SLEEPING(); CTR1(KTR_GEOM, "g_up processing task bp %p", bp); bp->bio_task(bp->bio_task_arg); -#ifdef WITNESS - mtx_unlock(&mymutex); -#endif + THREAD_SLEEPING_OK(); continue; } bp = g_bioq_first(&g_bio_run_up); if (bp != NULL) { g_bioq_unlock(&g_bio_run_up); -#ifdef WITNESS - mtx_lock(&mymutex); -#endif + THREAD_NO_SLEEPING(); CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off " "%ld len %ld", bp, bp->bio_to->name, bp->bio_offset, bp->bio_length); biodone(bp); -#ifdef WITNESS - mtx_unlock(&mymutex); -#endif + THREAD_SLEEPING_OK(); continue; } CTR0(KTR_GEOM, "g_up going to sleep"); ==== //depot/projects/smpng/sys/kern/kern_intr.c#69 (text+ko) ==== @@ -521,6 +521,7 @@ * another pass. */ atomic_store_rel_int(&ithd->it_need, 0); + THREAD_NO_SLEEPING(); restart: TAILQ_FOREACH(ih, &ithd->it_handlers, ih_next) { if (ithd->it_flags & IT_SOFT && !ih->ih_need) @@ -546,6 +547,7 @@ if ((ih->ih_flags & IH_MPSAFE) == 0) mtx_unlock(&Giant); } + THREAD_SLEEPING_OK(); /* * Interrupt storm handling: ==== //depot/projects/smpng/sys/kern/subr_sleepqueue.c#17 (text+ko) ==== @@ -269,6 +269,10 @@ MPASS(td->td_sleepqueue != NULL); MPASS(wchan != NULL); + /* If this thread is not allowed to sleep, die a horrible death. */ + KASSERT(!(td->td_pflags & TDP_NOSLEEPING), + ("trying to sleep while sleeping is prohibited")); + /* Look up the sleep queue associated with the wait channel 'wchan'. */ sq = sleepq_lookup(wchan); ==== //depot/projects/smpng/sys/modules/crash/crash.c#17 (text+ko) ==== @@ -383,7 +383,18 @@ } CRASH_EVENT("lock test1 mutex and then Giant", test_mtx_then_Giant); #endif - + +static void +test_no_sleeping(void) +{ + + printf("Should panic\n"); + THREAD_NO_SLEEPING(); + tsleep(&test1_mtx, curthread->td_priority, "sleep", 1); + THREAD_SLEEPING_OK(); +} +CRASH_EVENT("sleep while sleeping is prohibited", test_no_sleeping); + /* Help event should be last so that it is always event 1. */ static void ==== //depot/projects/smpng/sys/notes#53 (text+ko) ==== @@ -85,7 +85,7 @@ - fork counts? - Add a cache-line padded mtx_aligned union and use it for the mutex pools. - Robert wants intrcnt's for IPIs -- Add checks to msleep() and cv_wait*() to ensure they aren't called by an ++ Add checks to msleep() and cv_wait*() to ensure they aren't called by an interrupt thread. Would need to provide an exception for the istorm stuff. - Add witness checks to thread exit to make sure dying threads don't leak ==== //depot/projects/smpng/sys/sys/proc.h#148 (text+ko) ==== @@ -368,7 +368,7 @@ #define TDP_ALTSTACK 0x00000020 /* Have alternate signal stack. */ #define TDP_DEADLKTREAT 0x00000040 /* Lock aquisition - deadlock treatment. */ #define TDP_SA 0x00000080 /* A scheduler activation based thread. */ -#define TDP_UNUSED8 0x00000100 /* --available -- */ +#define TDP_NOSLEEPING 0x00000100 /* Thread is not allowed to sleep on a sq. */ #define TDP_OWEUPC 0x00000200 /* Call addupc() at next AST. */ #define TDP_UNUSED10 0x00000400 /* --available -- */ #define TDP_CAN_UNBIND 0x00000800 /* Only temporarily bound. */ @@ -793,6 +793,19 @@ /* Check whether a thread is safe to be swapped out. */ #define thread_safetoswapout(td) (TD_IS_SLEEPING(td) || TD_IS_SUSPENDED(td)) +/* Control whether or not it is safe for curthread to sleep. */ +#define THREAD_NO_SLEEPING() do { \ + KASSERT(!(curthread->td_pflags & TDP_NOSLEEPING), \ + ("nested no sleeping")); \ + curthread->td_pflags |= TDP_NOSLEEPING; \ +} while (0) + +#define THREAD_SLEEPING_OK() do { \ + KASSERT((curthread->td_pflags & TDP_NOSLEEPING), \ + ("nested sleeping ok")); \ + curthread->td_pflags &= ~TDP_NOSLEEPING; \ +} while (0) + /* Lock and unlock process arguments. */ #define PARGS_LOCK(p) mtx_lock(&pargs_ref_lock) #define PARGS_UNLOCK(p) mtx_unlock(&pargs_ref_lock)help
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