The following reply was made to PR kern/156567; it has been noted by GNATS.
From: dfil...@freebsd.org (dfilter service) To: bug-follo...@freebsd.org Cc: Subject: Re: kern/156567: commit references a PR Date: Wed, 29 Feb 2012 06:19:16 +0000 (UTC) Author: davidxu Date: Wed Feb 29 06:19:00 2012 New Revision: 232290 URL: http://svn.freebsd.org/changeset/base/232290 Log: MFC 230857: If multiple threads call kevent() to get AIO events on same kqueue fd, it is possible that a single AIO event will be reported to multiple threads, it is not threading friendly, and the existing API can not control this behavior. Allocate a kevent flags field sigev_notify_kevent_flags for AIO event notification in sigevent, and allow user to pass EV_CLEAR, EV_DISPATCH or EV_ONESHOT to AIO kernel code, user can control whether the event should be cleared once it is retrieved by a thread. This change should be comptaible with existing application, because the field should have already been zero-filled, and no additional action will be taken by kernel. PR: kern/156567 MFC 231006: Add 32-bit compat code for AIO kevent flags introduced in revision 230857. MFC 231724: Add notes about sigev_notify_kevent_flags introduced in revision 230857 which enables thread-friendly polling on same fd for AIO events. Reviewed by: delphij MFC 231777: Bump .Dd date for previous revision. Modified: stable/9/lib/libc/sys/kqueue.2 stable/9/sys/compat/freebsd32/freebsd32_signal.h stable/9/sys/kern/vfs_aio.c stable/9/sys/sys/signal.h Directory Properties: stable/9/lib/libc/ (props changed) stable/9/lib/libc/stdtime/ (props changed) stable/9/lib/libc/sys/ (props changed) stable/9/sys/ (props changed) stable/9/sys/amd64/include/xen/ (props changed) stable/9/sys/boot/ (props changed) stable/9/sys/boot/i386/efi/ (props changed) stable/9/sys/boot/ia64/efi/ (props changed) stable/9/sys/boot/ia64/ski/ (props changed) stable/9/sys/boot/powerpc/boot1.chrp/ (props changed) stable/9/sys/boot/powerpc/ofw/ (props changed) stable/9/sys/cddl/contrib/opensolaris/ (props changed) stable/9/sys/conf/ (props changed) stable/9/sys/contrib/dev/acpica/ (props changed) stable/9/sys/contrib/octeon-sdk/ (props changed) stable/9/sys/contrib/pf/ (props changed) stable/9/sys/contrib/x86emu/ (props changed) stable/9/sys/i386/conf/XENHVM (props changed) Modified: stable/9/lib/libc/sys/kqueue.2 ============================================================================== --- stable/9/lib/libc/sys/kqueue.2 Wed Feb 29 05:48:29 2012 (r232289) +++ stable/9/lib/libc/sys/kqueue.2 Wed Feb 29 06:19:00 2012 (r232290) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd September 15, 2009 +.Dd February 15, 2012 .Dt KQUEUE 2 .Os .Sh NAME @@ -322,6 +322,9 @@ The sigevent portion of the AIO request .Va sigev_notify_kqueue containing the descriptor of the kqueue that the event should be attached to, +.Va sigev_notify_kevent_flags +containing the kevent flags which should be EV_ONESHOT, EV_CLEAR or +EV_DISPATCH, .Va sigev_value containing the udata value, and .Va sigev_notify Modified: stable/9/sys/compat/freebsd32/freebsd32_signal.h ============================================================================== --- stable/9/sys/compat/freebsd32/freebsd32_signal.h Wed Feb 29 05:48:29 2012 (r232289) +++ stable/9/sys/compat/freebsd32/freebsd32_signal.h Wed Feb 29 06:19:00 2012 (r232290) @@ -92,6 +92,7 @@ struct sigevent32 { uint32_t _function; uint32_t _attribute; } _sigev_thread; + unsigned short _kevent_flags; uint32_t __spare__[8]; } _sigev_un; }; Modified: stable/9/sys/kern/vfs_aio.c ============================================================================== --- stable/9/sys/kern/vfs_aio.c Wed Feb 29 05:48:29 2012 (r232289) +++ stable/9/sys/kern/vfs_aio.c Wed Feb 29 06:19:00 2012 (r232290) @@ -1524,6 +1524,7 @@ aio_aqueue(struct thread *td, struct aio int error; int fd, kqfd; int jid; + u_short evflags; if (p->p_aioinfo == NULL) aio_init_aioinfo(p); @@ -1640,10 +1641,15 @@ aio_aqueue(struct thread *td, struct aio if (aiocbe->uaiocb.aio_sigevent.sigev_notify != SIGEV_KEVENT) goto no_kqueue; + evflags = aiocbe->uaiocb.aio_sigevent.sigev_notify_kevent_flags; + if ((evflags & ~(EV_CLEAR | EV_DISPATCH | EV_ONESHOT)) != 0) { + error = EINVAL; + goto aqueue_fail; + } kqfd = aiocbe->uaiocb.aio_sigevent.sigev_notify_kqueue; kev.ident = (uintptr_t)aiocbe->uuaiocb; kev.filter = EVFILT_AIO; - kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1; + kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1 | evflags; kev.data = (intptr_t)aiocbe; kev.udata = aiocbe->uaiocb.aio_sigevent.sigev_value.sival_ptr; error = kqfd_register(kqfd, &kev, td, 1); @@ -2688,6 +2694,7 @@ convert_sigevent32(struct sigevent32 *si break; case SIGEV_KEVENT: CP(*sig32, *sig, sigev_notify_kqueue); + CP(*sig32, *sig, sigev_notify_kevent_flags); PTRIN_CP(*sig32, *sig, sigev_value.sival_ptr); break; default: Modified: stable/9/sys/sys/signal.h ============================================================================== --- stable/9/sys/sys/signal.h Wed Feb 29 05:48:29 2012 (r232289) +++ stable/9/sys/sys/signal.h Wed Feb 29 06:19:00 2012 (r232290) @@ -169,12 +169,14 @@ struct sigevent { void (*_function)(union sigval); void *_attribute; /* pthread_attr_t * */ } _sigev_thread; + unsigned short _kevent_flags; long __spare__[8]; } _sigev_un; }; #if __BSD_VISIBLE #define sigev_notify_kqueue sigev_signo +#define sigev_notify_kevent_flags _sigev_un._kevent_flags #define sigev_notify_thread_id _sigev_un._threadid #endif #define sigev_notify_function _sigev_un._sigev_thread._function _______________________________________________ svn-src-...@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org" _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
