kern/156567: commit references a PR

dfilter service dfilter at FreeBSD.ORG
Wed Feb 29 06:20:09 UTC 2012


The following reply was made to PR kern/156567; it has been noted by GNATS.

From: dfilter at FreeBSD.ORG (dfilter service)
To: bug-followup at 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
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