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From: Jamie Lokier <jamie@shareable.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: john stultz <johnstul@us.ibm.com>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] linux-2.6.2-rc2_vsyscall-gtod_B1.patch
Date: Thu, 29 Jan 2004 13:26:23 +0000	[thread overview]
Message-ID: <20040129132623.GB13225@mail.shareable.org> (raw)
In-Reply-To: <401894DA.7000609@redhat.com>

Ulrich Drepper wrote:
> ~ alternatively use the symbol table the vdso has.  Export the new code
> only via the symbol table.  No fixed address for the function, the
> runtime gets it from the symbol table.  glibc will use weak symbol
> references; if the symbol isn't there, the old code is used.  This will
> require that every single optimized syscall needs to be handled special.
> 
> 
> I personally like the first approach better.  The indirection table can
> maintained in sync with the syscall table inside the kernel.  It all
> comes at all times from the same source.  The overhead of the memory
> load should be neglectable.

I like the second approach more.  You can change glibc to look up the
weak symbol for _all_ syscalls, then none of them are special and it
will work with future kernel optimisations.

-- Jamie

  reply	other threads:[~2004-01-29 13:26 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-29  2:46 [RFC][PATCH] linux-2.6.2-rc2_vsyscall-gtod_B1.patch john stultz
2004-01-29  5:06 ` Ulrich Drepper
2004-01-29 13:26   ` Jamie Lokier [this message]
2004-01-29 18:05     ` Ulrich Drepper
2004-01-29 19:15       ` Jamie Lokier
2004-01-29 23:59         ` john stultz
2004-01-30  0:40           ` Ulrich Drepper
2004-01-30  0:31         ` Ulrich Drepper
2004-01-30  4:17           ` Jamie Lokier
2004-01-30  5:09             ` Ulrich Drepper
2004-01-30  9:29               ` Ingo Molnar
2004-02-03  4:38                 ` Ulrich Drepper
2004-01-30 17:34               ` Jamie Lokier
2004-01-30  8:33             ` Jakub Jelinek
2004-01-30 17:21               ` Jamie Lokier
2004-01-31  0:10     ` Eric W. Biederman
2004-01-31  2:41       ` Jamie Lokier
2004-01-31  5:54         ` Eric W. Biederman
2004-02-01  1:28   ` Andrea Arcangeli
2004-02-03  4:35     ` Ulrich Drepper
2004-02-03  5:34       ` Andrea Arcangeli
2004-02-03  8:52       ` Jamie Lokier
2004-02-03 16:25         ` Andrea Arcangeli
2004-02-03 17:37           ` Jamie Lokier
2004-02-03 18:10             ` Andrea Arcangeli
2004-02-03 18:23               ` Jamie Lokier
2004-02-03 18:34                 ` Andrea Arcangeli
2004-01-31  0:17 ` Eric W. Biederman
2004-01-31  2:20   ` john stultz
     [not found] <1075344395.1592.87.camel@cog.beaverton.ibm.com.suse.lists.linux.kernel>
     [not found] ` <401894DA.7000609@redhat.com.suse.lists.linux.kernel>
     [not found]   ` <20040201012803.GN26076@dualathlon.random.suse.lists.linux.kernel>
     [not found]     ` <401F251C.2090300@redhat.com.suse.lists.linux.kernel>
     [not found]       ` <20040203085224.GA15738@mail.shareable.org.suse.lists.linux.kernel>
     [not found]         ` <20040203162515.GY26076@dualathlon.random.suse.lists.linux.kernel>
     [not found]           ` <20040203173716.GC17895@mail.shareable.org.suse.lists.linux.kernel>
     [not found]             ` <20040203181001.GA26076@dualathlon.random.suse.lists.linux.kernel>
     [not found]               ` <20040203182310.GA18326@mail.shareable.org.suse.lists.linux.kernel>
2004-02-04  2:27                 ` Andi Kleen
2004-02-04  2:40                   ` Andrea Arcangeli
2004-02-04  4:21                   ` Jamie Lokier
2004-02-05 21:43                     ` Andrea Arcangeli
2004-02-06  4:15                       ` Rik van Riel
2004-02-06  4:28                         ` Andrea Arcangeli
2004-02-06  9:23                           ` Ulrich Drepper
2004-02-06 15:49                             ` Andrea Arcangeli
2004-02-07  0:37                               ` Ulrich Drepper
2004-02-07  2:19                                 ` Andrea Arcangeli
2004-02-07  3:37                                   ` Daniel Jacobowitz
2004-02-07  4:36                                     ` Andrea Arcangeli
2004-02-07  4:53                                       ` Jamie Lokier

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