From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: 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,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: [PATCH 7/7] uprobes: kill uprobes_srcu/uprobe_srcu_id
Date: Wed, 30 May 2012 01:04:47 +0200 [thread overview]
Message-ID: <1338332687.26856.189.camel@twins> (raw)
In-Reply-To: <20120529193008.GG8057@redhat.com>
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..
next prev parent reply other threads:[~2012-05-29 23:05 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-29 19:27 [PATCH 0/7] " 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 [this message]
2012-05-30 1:51 ` Paul E. McKenney
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
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