From: Florian Weimer <fweimer@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: carlos <carlos@redhat.com>,
Joseph Myers <joseph@codesourcery.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
libc-alpha <libc-alpha@sourceware.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ben Maurer <bmaurer@fb.com>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Will Deacon <will.deacon@arm.com>,
Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
Rich Felker <dalias@libc.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-api <linux-api@vger.kernel.org>
Subject: Re: [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at nptl init and thread creation (v4)
Date: Mon, 14 Jan 2019 18:55:00 -0000 [thread overview]
Message-ID: <87fttv9iic.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <1681283664.1380.1547152315426.JavaMail.zimbra@efficios.com> (Mathieu Desnoyers's message of "Thu, 10 Jan 2019 15:31:55 -0500 (EST)")
* Mathieu Desnoyers:
> Therefore, both symbols will end up in
> sysdeps/unix/sysv/linux/Versions.
I'm not sure what you mean by that. The physical location in the
directory tree has little effect on which shared object the symbol is
placed in; that will need other changes.
>> By the way, you could avoid the need for unregistration if you allocated
>> the rseq areas persistently, index by TID. They are quite small, so
>> with the typical PID range, maybe the wasted memory due to changing TIDs
>> would be acceptable?
>
> Would we be able to access those __rseq_abi as normal TLS IE model
> variables ? The overhead of indexing an array matters for a
> fast-path.
No, that wouldn't be possible in this case. You would need another
indirection.
Thanks,
Florian
next prev parent reply other threads:[~2019-01-14 18:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 19:22 Mathieu Desnoyers
2018-12-04 19:22 ` [RFC PATCH glibc 2/4] glibc: sched_getcpu(): use rseq cpu_id TLS on Linux Mathieu Desnoyers
2018-12-04 19:22 ` [RFC PATCH glibc 3/4] support record failure: allow use from constructor Mathieu Desnoyers
2018-12-04 19:22 ` [RFC PATCH glibc 4/4] rseq registration tests Mathieu Desnoyers
2018-12-04 19:44 ` [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at nptl init and thread creation (v4) Florian Weimer
2018-12-04 19:50 ` Mathieu Desnoyers
2018-12-11 11:13 ` Florian Weimer
2019-01-10 20:32 ` Mathieu Desnoyers
2019-01-11 1:12 ` Mathieu Desnoyers
2019-01-14 18:57 ` Florian Weimer
2019-01-14 18:55 ` Florian Weimer [this message]
2019-01-14 19:22 ` Mathieu Desnoyers
2019-01-14 19:37 ` Florian Weimer
2019-01-14 20:27 ` Mathieu Desnoyers
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