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From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	Anton Blanchard <anton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
	torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
	Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify
Date: Thu, 17 Sep 2009 08:45:29 -0700	[thread overview]
Message-ID: <adatyz1d17q.fsf@cisco.com> (raw)
In-Reply-To: <adazl8td35u.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org> (Roland Dreier's message of "Thu, 17 Sep 2009 08:03:25 -0700")


 > > > Hmm, or are you saying you can only get 1 event per registered range and
 > > > allocate the thing on registration? That'd need some registration limit
 > > > to avoid DoS scenarios.
 > > 
 > > Yes, that's what I do.  You're right, I should add a limit... although
 > > their are lots of ways for userspace to consume arbitrary amounts of
 > > kernel resources already.
 > 
 > I'd be good to work at reducing that number, not adding to it ;-)

Yes, definitely.  I'll add a quick ummunotify module parameter that
limits the number of registrations per process.

 > But yeah, I currently don't see a very nice match to perf counters.

OK.  It would be nice to tie into something more general, but I think I
agree -- perf counters are missing the filtering and the "no lost
events" that ummunotify does have.  And I'm not sure it's worth messing
up the perf counters design just to jam one more not totally related
thing in.

 - R.
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WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier@cisco.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paul Mackerras <paulus@samba.org>,
	Anton Blanchard <anton@samba.org>,
	general@lists.openfabrics.org, akpm@linux-foundation.org,
	torvalds@linux-foundation.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify
Date: Thu, 17 Sep 2009 08:45:29 -0700	[thread overview]
Message-ID: <adatyz1d17q.fsf@cisco.com> (raw)
In-Reply-To: <adazl8td35u.fsf@cisco.com> (Roland Dreier's message of "Thu, 17 Sep 2009 08:03:25 -0700")


 > > > Hmm, or are you saying you can only get 1 event per registered range and
 > > > allocate the thing on registration? That'd need some registration limit
 > > > to avoid DoS scenarios.
 > > 
 > > Yes, that's what I do.  You're right, I should add a limit... although
 > > their are lots of ways for userspace to consume arbitrary amounts of
 > > kernel resources already.
 > 
 > I'd be good to work at reducing that number, not adding to it ;-)

Yes, definitely.  I'll add a quick ummunotify module parameter that
limits the number of registrations per process.

 > But yeah, I currently don't see a very nice match to perf counters.

OK.  It would be nice to tie into something more general, but I think I
agree -- perf counters are missing the filtering and the "no lost
events" that ummunotify does have.  And I'm not sure it's worth messing
up the perf counters design just to jam one more not totally related
thing in.

 - R.

  parent reply	other threads:[~2009-09-17 15:45 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-11  4:38 [GIT PULL] please pull ummunotify Roland Dreier
2009-09-11  4:38 ` Roland Dreier
2009-09-15 11:34 ` Pavel Machek
     [not found]   ` <20090915113434.GF1328-+ZI9xUNit7I@public.gmane.org>
2009-09-15 14:57     ` [ofa-general] " Roland Dreier
2009-09-15 14:57       ` Roland Dreier
     [not found]       ` <ada7hw0gsqz.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-28 20:49         ` Pavel Machek
2009-09-28 20:49           ` Pavel Machek
     [not found]           ` <20090928204923.GA1960-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org>
2009-09-28 21:40             ` Jason Gunthorpe
2009-09-28 21:40               ` Jason Gunthorpe
     [not found] ` <aday6omhz9d.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-11  5:56   ` KOSAKI Motohiro
2009-09-11  5:56     ` KOSAKI Motohiro
2009-09-11  6:03     ` [ofa-general] " Roland Dreier
2009-09-11  6:03       ` Roland Dreier
     [not found]       ` <adatyzahvbm.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-11  6:11         ` KOSAKI Motohiro
2009-09-11  6:11           ` KOSAKI Motohiro
     [not found]           ` <20090911150552.DB68.A69D9226-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2009-09-11 16:42             ` Gleb Natapov
2009-09-11 16:42               ` Gleb Natapov
2009-09-11  6:15       ` Brice Goglin
     [not found]         ` <4AA9EAF7.5010401-MZpvjPyXg2s@public.gmane.org>
2009-09-11  6:21           ` KOSAKI Motohiro
2009-09-11  6:21             ` KOSAKI Motohiro
2009-09-11  6:22           ` Roland Dreier
2009-09-11  6:22             ` Roland Dreier
2009-09-11  6:40             ` [ofa-general] " Jason Gunthorpe
2009-09-11  6:40               ` Jason Gunthorpe
     [not found]               ` <20090911064019.GZ4973-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2009-09-11 16:58                 ` Roland Dreier
2009-09-11 16:58                   ` Roland Dreier
     [not found]                   ` <adaljklifkt.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-15  7:03                     ` KOSAKI Motohiro
2009-09-15  7:03                       ` KOSAKI Motohiro
2009-09-15  8:27                       ` Roland Dreier
2009-09-15  8:27                         ` Roland Dreier
2009-09-15 12:38                       ` Jeff Squyres
2009-09-15 12:38                         ` Jeff Squyres
2009-09-16 16:30   ` Roland Dreier
2009-09-16 16:30     ` Roland Dreier
2009-09-16 16:40     ` [ofa-general] " Linus Torvalds
2009-09-16 16:40       ` Linus Torvalds
2009-09-17 11:30   ` Peter Zijlstra
2009-09-17 11:30     ` Peter Zijlstra
2009-09-17 14:24     ` [ofa-general] " Roland Dreier
     [not found]       ` <adafxalejiq.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 14:32         ` Roland Dreier
2009-09-17 14:32           ` Roland Dreier
     [not found]           ` <adaab0tej5c.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 14:49             ` Peter Zijlstra
2009-09-17 14:49               ` Peter Zijlstra
2009-09-17 15:03               ` Roland Dreier
2009-09-17 15:03                 ` Roland Dreier
     [not found]                 ` <adazl8td35u.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 15:22                   ` Peter Zijlstra
2009-09-17 15:22                     ` Peter Zijlstra
2009-09-17 15:45                   ` Roland Dreier [this message]
2009-09-17 15:45                     ` Roland Dreier
     [not found]                     ` <adatyz1d17q.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-18 11:50                       ` Ingo Molnar
2009-09-18 11:50                         ` Ingo Molnar
2009-09-29 17:13                       ` Pavel Machek
2009-09-29 17:13                         ` Pavel Machek
     [not found]                         ` <20090929171332.GD14405-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org>
2009-09-30  9:44                           ` Ingo Molnar
2009-09-30  9:44                             ` Ingo Molnar
     [not found]                             ` <20090930094456.GD24621-X9Un+BFzKDI@public.gmane.org>
2009-09-30 16:02                               ` Jason Gunthorpe
2009-09-30 16:02                                 ` Jason Gunthorpe
     [not found]                                 ` <20090930160232.GZ22310-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2009-10-12 18:19                                   ` Ingo Molnar
2009-10-12 18:19                                     ` Ingo Molnar
     [not found]                                     ` <20091012181944.GF17138-X9Un+BFzKDI@public.gmane.org>
2009-10-12 19:30                                       ` Jason Gunthorpe
2009-10-12 19:30                                         ` Jason Gunthorpe
2009-10-12 20:20                                         ` Ingo Molnar
     [not found]                                           ` <20091012202046.GA7648-X9Un+BFzKDI@public.gmane.org>
2009-10-13  4:05                                             ` Jason Gunthorpe
2009-10-13  4:05                                               ` Jason Gunthorpe
2009-10-13  6:40                                               ` Ingo Molnar
     [not found]                                                 ` <20091013064006.GC9470-X9Un+BFzKDI@public.gmane.org>
2009-10-13 16:27                                                   ` Jason Gunthorpe
2009-10-13 16:27                                                     ` Jason Gunthorpe
2009-10-13  5:43                                           ` Brice Goglin
     [not found]                                             ` <4AD41373.8010108-MZpvjPyXg2s@public.gmane.org>
2009-10-13  6:38                                               ` Ingo Molnar
2009-10-13  6:38                                                 ` Ingo Molnar
2009-09-30 17:06                               ` Roland Dreier
2009-09-30 17:06                                 ` Roland Dreier
2009-10-02 16:32                               ` Roland Dreier
2009-10-02 16:32                                 ` Roland Dreier
     [not found]                                 ` <ada3a61rc3j.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-10-02 20:45                                   ` Pavel Machek
2009-10-02 20:45                                     ` Pavel Machek
2009-10-07 22:34                                   ` Roland Dreier
2009-10-07 22:34                                     ` Roland Dreier
     [not found]                                     ` <ada3a5uq1dk.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-10-12 17:33                                       ` Peter Zijlstra
2009-10-12 17:33                                         ` Peter Zijlstra
2009-09-17 14:43         ` Peter Zijlstra
2009-09-17 14:43           ` Peter Zijlstra

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