From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/7] uprobes: kill uprobes_srcu/uprobe_srcu_id
Date: Tue, 29 May 2012 18:51:57 -0700 [thread overview]
Message-ID: <20120530015157.GB2357@linux.vnet.ibm.com> (raw)
In-Reply-To: <1338332687.26856.189.camel@twins>
On Wed, May 30, 2012 at 01:04:47AM +0200, Peter Zijlstra wrote:
> On Tue, 2012-05-29 at 21:30 +0200, Oleg Nesterov wrote:
> > Kill the no longer needed uprobes_srcu/uprobe_srcu_id code.
> >
> > It doesn't really work anyway. synchronize_srcu() can only synchronize
> > with the code "inside" the srcu_read_lock/srcu_read_unlock section,
> > while uprobe_pre_sstep_notifier() does srcu_read_lock() _after_ we
> > already hit the breakpoint.
> >
> > I guess this probably works "in practice". synchronize_srcu() is slow
> > and it implies synchronize_sched(), and the probed task enters the non-
> > preemptible section at the start of exception handler. Still this is not
> > right at least in theory, and task->uprobe_srcu_id blows task_struct.
>
> This kills the only user of srcu_read_{,un}lock_raw(), so I guess we
> could also make:
>
> 9ceae0e2
> 101db7b4
> 0c53dd8b
>
> go away..
If it is still unused in a few months, I will get rid of them.
Thanx, Paul
next prev parent reply other threads:[~2012-05-30 1:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-29 19:27 [PATCH 0/7] uprobes: kill uprobes_srcu/uprobe_srcu_id Oleg Nesterov
2012-05-29 19:27 ` [PATCH 1/7] uprobes: optimize is_swbp_at_addr() for current->mm Oleg Nesterov
2012-06-06 15:08 ` [tip:perf/core] uprobes: Optimize is_swbp_at_addr() for current-%3Emm tip-bot for Oleg Nesterov
2012-06-06 16:05 ` [tip:perf/core] uprobes: Optimize is_swbp_at_addr() for current-> mm tip-bot for Oleg Nesterov
2012-05-29 19:27 ` [PATCH 2/7] uprobes: change read_opcode() to use FOLL_FORCE Oleg Nesterov
2012-06-06 15:09 ` [tip:perf/core] uprobes: Change " tip-bot for Oleg Nesterov
2012-06-06 16:06 ` tip-bot for Oleg Nesterov
2012-05-29 19:28 ` [PATCH 3/7] uprobes: introduce find_active_uprobe() helper Oleg Nesterov
2012-06-06 15:10 ` [tip:perf/core] uprobes: Introduce " tip-bot for Oleg Nesterov
2012-06-06 16:07 ` tip-bot for Oleg Nesterov
2012-05-29 19:29 ` [PATCH 4/7] uprobes: teach find_active_uprobe() to provide the "is_swbp" info Oleg Nesterov
2012-06-06 15:10 ` [tip:perf/core] uprobes: Teach find_active_uprobe() to provide the %22is_swbp%22 info tip-bot for Oleg Nesterov
2012-06-06 16:08 ` [tip:perf/core] uprobes: Teach find_active_uprobe() to provide the "is_swbp" info tip-bot for Oleg Nesterov
2012-05-29 19:29 ` [PATCH 5/7] uprobes: change register_for_each_vma() to take mm->mmap_sem for writing Oleg Nesterov
2012-06-06 15:11 ` [tip:perf/core] uprobes: Change register_for_each_vma() to take mm-%3Emmap_sem " tip-bot for Oleg Nesterov
2012-06-06 16:09 ` [tip:perf/core] uprobes: Change register_for_each_vma() to take mm->mmap_sem " tip-bot for Oleg Nesterov
2012-05-29 19:29 ` [PATCH 6/7] uprobes: teach handle_swbp() to rely on "is_swbp" rather than uprobes_srcu Oleg Nesterov
2012-06-06 15:12 ` [tip:perf/core] uprobes: Teach handle_swbp() to rely on %22is_swbp%22 " tip-bot for Oleg Nesterov
2012-06-06 16:10 ` [tip:perf/core] uprobes: Teach handle_swbp() to rely on "is_swbp" " tip-bot for Oleg Nesterov
2012-05-29 19:30 ` [PATCH 7/7] uprobes: kill uprobes_srcu/uprobe_srcu_id Oleg Nesterov
2012-05-29 23:04 ` Peter Zijlstra
2012-05-30 1:51 ` Paul E. McKenney [this message]
2012-06-06 15:13 ` [tip:perf/core] uprobes: Kill uprobes_srcu/uprobe_srcu_id tip-bot for Oleg Nesterov
2012-06-06 16:10 ` tip-bot for Oleg Nesterov
2012-05-31 5:40 ` [PATCH 0/7] uprobes: kill uprobes_srcu/uprobe_srcu_id Srikar Dronamraju
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120530015157.GB2357@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=ananth@in.ibm.com \
--cc=anton@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=masami.hiramatsu.pt@hitachi.com \
--cc=mingo@elte.hu \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=srikar@linux.vnet.ibm.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.