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From: Andy Lutomirski <luto@kernel.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>, Andy Lutomirski <luto@kernel.org>,
	"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>
Subject: Re: Potential race in TLB flush batching?
Date: Wed, 12 Jul 2017 16:36:13 -0700	[thread overview]
Message-ID: <CALCETrXr16TGe1gxnPajqpq-G8z1hK_fzPzZiJa+h+zZ8RysNw@mail.gmail.com> (raw)
In-Reply-To: <591A2865-13B8-4B3A-B094-8B83A7F9814B@gmail.com>

On Wed, Jul 12, 2017 at 4:27 PM, Nadav Amit <nadav.amit@gmail.com> wrote:
>
> Actually, I think that based on Andy’s patches there is a relatively
> reasonable solution. For each mm we will hold both a “pending_tlb_gen”
> (increased under the PT-lock) and an “executed_tlb_gen”. Once
> flush_tlb_mm_range finishes flushing it will use cmpxchg to update the
> executed_tlb_gen to the pending_tlb_gen that was prior the flush (the
> cmpxchg will ensure the TLB gen only goes forward). Then, whenever
> pending_tlb_gen is different than executed_tlb_gen - a flush is needed.
>

Why do we need executed_tlb_gen?  We already have
cpu_tlbstate.ctxs[...].tlb_gen.  Or is the idea that executed_tlb_gen
guarantees that all cpus in mm_cpumask are at least up to date to
executed_tlb_gen?

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  reply	other threads:[~2017-07-12 23:36 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-11  0:52 Potential race in TLB flush batching? Nadav Amit
2017-07-11  6:41 ` Mel Gorman
2017-07-11  7:30   ` Nadav Amit
2017-07-11  9:29     ` Mel Gorman
2017-07-11 10:40       ` Nadav Amit
2017-07-11 13:20         ` Mel Gorman
2017-07-11 14:58           ` Andy Lutomirski
2017-07-11 15:53             ` Mel Gorman
2017-07-11 17:23               ` Andy Lutomirski
2017-07-11 19:18                 ` Mel Gorman
2017-07-11 20:06                   ` Nadav Amit
2017-07-11 21:09                     ` Mel Gorman
2017-07-11 20:09                   ` Mel Gorman
2017-07-11 21:52                     ` Mel Gorman
2017-07-11 22:27                       ` Nadav Amit
2017-07-11 22:34                         ` Nadav Amit
2017-07-12  8:27                         ` Mel Gorman
2017-07-12 23:27                           ` Nadav Amit
2017-07-12 23:36                             ` Andy Lutomirski [this message]
2017-07-12 23:42                               ` Nadav Amit
2017-07-13  5:38                                 ` Andy Lutomirski
2017-07-13 16:05                                   ` Nadav Amit
2017-07-13 16:06                                     ` Andy Lutomirski
2017-07-13  6:07                             ` Mel Gorman
2017-07-13 16:08                               ` Andy Lutomirski
2017-07-13 17:07                                 ` Mel Gorman
2017-07-13 17:15                                   ` Andy Lutomirski
2017-07-13 18:23                                     ` Mel Gorman
2017-07-14 23:16                               ` Nadav Amit
2017-07-15 15:55                                 ` Mel Gorman
2017-07-15 16:41                                   ` Andy Lutomirski
2017-07-17  7:49                                     ` Mel Gorman
2017-07-18 21:28                                   ` Nadav Amit
2017-07-19  7:41                                     ` Mel Gorman
2017-07-19 19:41                                       ` Nadav Amit
2017-07-19 19:58                                         ` Mel Gorman
2017-07-19 20:20                                           ` Nadav Amit
2017-07-19 21:47                                             ` Mel Gorman
2017-07-19 22:19                                               ` Nadav Amit
2017-07-19 22:59                                                 ` Mel Gorman
2017-07-19 23:39                                                   ` Nadav Amit
2017-07-20  7:43                                                     ` Mel Gorman
2017-07-22  1:19                                                       ` Nadav Amit
2017-07-24  9:58                                                         ` Mel Gorman
2017-07-24 19:46                                                           ` Nadav Amit
2017-07-25  7:37                                                           ` Minchan Kim
2017-07-25  8:51                                                             ` Mel Gorman
2017-07-25  9:11                                                               ` Minchan Kim
2017-07-25 10:10                                                                 ` Mel Gorman
2017-07-26  5:43                                                                   ` Minchan Kim
2017-07-26  9:22                                                                     ` Mel Gorman
2017-07-26 19:18                                                                       ` Nadav Amit
2017-07-26 23:40                                                                         ` Minchan Kim
2017-07-27  0:09                                                                           ` Nadav Amit
2017-07-27  0:34                                                                             ` Minchan Kim
2017-07-27  0:48                                                                               ` Nadav Amit
2017-07-27  1:13                                                                                 ` Nadav Amit
2017-07-27  7:04                                                                                   ` Minchan Kim
2017-07-27  7:21                                                                                     ` Mel Gorman
2017-07-27 16:04                                                                                       ` Nadav Amit
2017-07-27 17:36                                                                                         ` Mel Gorman
2017-07-26 23:44                                                                       ` Minchan Kim
2017-07-11 22:07                   ` Andy Lutomirski
2017-07-11 22:33                     ` Mel Gorman
2017-07-14  7:00                     ` Benjamin Herrenschmidt
2017-07-14  8:31                       ` Mel Gorman
2017-07-14  9:02                         ` Benjamin Herrenschmidt
2017-07-14  9:27                           ` Mel Gorman
2017-07-14 22:21                             ` Andy Lutomirski
2017-07-11 16:22           ` Nadav Amit

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