From: Andy Lutomirski <luto@kernel.org> To: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@alien8.de>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, "linux-mm@kvack.org" <linux-mm@kvack.org>, Nadav Amit <nadav.amit@gmail.com>, Rik van Riel <riel@redhat.com>, Dave Hansen <dave.hansen@intel.com>, Arjan van de Ven <arjan@linux.intel.com> Subject: Re: [PATCH v4 10/10] x86/mm: Try to preserve old TLB entries using PCID Date: Tue, 18 Jul 2017 10:06:15 -0700 [thread overview] Message-ID: <CALCETrVyY-Bvh8GkwqpC9eL4D0QnkVEjpYmwvPhTJBa9evwqtQ@mail.gmail.com> (raw) In-Reply-To: <20170718085341.nlt35dph4oukb4tc@gmail.com> On Tue, Jul 18, 2017 at 1:53 AM, Ingo Molnar <mingo@kernel.org> wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > >> On Wed, Jul 05, 2017 at 09:04:39AM -0700, Andy Lutomirski wrote: >> > On Wed, Jul 5, 2017 at 5:18 AM, Peter Zijlstra <peterz@infradead.org> wrote: >> > > On Thu, Jun 29, 2017 at 08:53:22AM -0700, Andy Lutomirski wrote: >> > >> @@ -104,18 +140,20 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, >> > >> >> > >> /* Resume remote flushes and then read tlb_gen. */ >> > >> cpumask_set_cpu(cpu, mm_cpumask(next)); >> > > >> > > Barriers should have a comment... what is being ordered here against >> > > what? >> > >> > How's this comment? >> > >> > /* >> > * Resume remote flushes and then read tlb_gen. We need to do >> > * it in this order: any inc_mm_tlb_gen() caller that writes a >> > * larger tlb_gen than we read here must see our cpu set in >> > * mm_cpumask() so that it will know to flush us. The barrier >> > * here synchronizes with inc_mm_tlb_gen(). >> > */ >> >> Slightly confusing, you mean this, right? >> >> >> cpumask_set_cpu(cpu, mm_cpumask()); inc_mm_tlb_gen(); >> >> MB MB >> >> next_tlb_gen = atomic64_read(&next->context.tlb_gen); flush_tlb_others(mm_cpumask()); >> >> >> which seems to make sense. > > Btw., I'll wait for a v5 iteration before applying this last patch to tip:x86/mm. I'll send it shortly. I think I'll also add a patch to factor out the flush calls a bit more to prepare for Mel's upcoming fix. > > Thanks, > > Ingo
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org> To: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@alien8.de>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, "linux-mm@kvack.org" <linux-mm@kvack.org>, Nadav Amit <nadav.amit@gmail.com>, Rik van Riel <riel@redhat.com>, Dave Hansen <dave.hansen@intel.com>, Arjan van de Ven <arjan@linux.intel.com> Subject: Re: [PATCH v4 10/10] x86/mm: Try to preserve old TLB entries using PCID Date: Tue, 18 Jul 2017 10:06:15 -0700 [thread overview] Message-ID: <CALCETrVyY-Bvh8GkwqpC9eL4D0QnkVEjpYmwvPhTJBa9evwqtQ@mail.gmail.com> (raw) In-Reply-To: <20170718085341.nlt35dph4oukb4tc@gmail.com> On Tue, Jul 18, 2017 at 1:53 AM, Ingo Molnar <mingo@kernel.org> wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > >> On Wed, Jul 05, 2017 at 09:04:39AM -0700, Andy Lutomirski wrote: >> > On Wed, Jul 5, 2017 at 5:18 AM, Peter Zijlstra <peterz@infradead.org> wrote: >> > > On Thu, Jun 29, 2017 at 08:53:22AM -0700, Andy Lutomirski wrote: >> > >> @@ -104,18 +140,20 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, >> > >> >> > >> /* Resume remote flushes and then read tlb_gen. */ >> > >> cpumask_set_cpu(cpu, mm_cpumask(next)); >> > > >> > > Barriers should have a comment... what is being ordered here against >> > > what? >> > >> > How's this comment? >> > >> > /* >> > * Resume remote flushes and then read tlb_gen. We need to do >> > * it in this order: any inc_mm_tlb_gen() caller that writes a >> > * larger tlb_gen than we read here must see our cpu set in >> > * mm_cpumask() so that it will know to flush us. The barrier >> > * here synchronizes with inc_mm_tlb_gen(). >> > */ >> >> Slightly confusing, you mean this, right? >> >> >> cpumask_set_cpu(cpu, mm_cpumask()); inc_mm_tlb_gen(); >> >> MB MB >> >> next_tlb_gen = atomic64_read(&next->context.tlb_gen); flush_tlb_others(mm_cpumask()); >> >> >> which seems to make sense. > > Btw., I'll wait for a v5 iteration before applying this last patch to tip:x86/mm. I'll send it shortly. I think I'll also add a patch to factor out the flush calls a bit more to prepare for Mel's upcoming fix. > > Thanks, > > Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-07-18 17:06 UTC|newest] Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-29 15:53 [PATCH v4 00/10] PCID and improved laziness Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 01/10] x86/mm: Don't reenter flush_tlb_func_common() Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-06-30 13:11 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 02/10] x86/mm: Delete a big outdated comment about TLB flushing Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-06-30 13:11 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 03/10] x86/mm: Give each mm TLB flush generation a unique ID Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:31 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-07-05 10:58 ` Peter Zijlstra 2017-06-29 15:53 ` [PATCH v4 04/10] x86/mm: Track the TLB's tlb_gen and update the flushing algorithm Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:31 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 05/10] x86/mm: Rework lazy TLB mode and TLB freshness tracking Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:31 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 06/10] x86/mm: Stop calling leave_mm() in idle code Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:32 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 07/10] x86/mm: Disable PCID on 32-bit kernels Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:32 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 08/10] x86/mm: Add nopcid to turn off PCID Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:32 ` [tip:x86/mm] x86/mm: Add the 'nopcid' boot option " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 09/10] x86/mm: Enable CR4.PCIDE on supported systems Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-05 10:33 ` [tip:x86/mm] " tip-bot for Andy Lutomirski 2017-06-29 15:53 ` [PATCH v4 10/10] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski 2017-06-29 15:53 ` Andy Lutomirski 2017-07-03 10:56 ` Thomas Gleixner 2017-07-03 10:56 ` Thomas Gleixner 2017-07-05 12:18 ` Peter Zijlstra 2017-07-05 12:18 ` Peter Zijlstra 2017-07-05 16:04 ` Andy Lutomirski 2017-07-05 16:04 ` Andy Lutomirski 2017-07-05 17:02 ` Peter Zijlstra 2017-07-05 17:02 ` Peter Zijlstra 2017-07-18 8:53 ` Ingo Molnar 2017-07-18 8:53 ` Ingo Molnar 2017-07-18 17:06 ` Andy Lutomirski [this message] 2017-07-18 17:06 ` Andy Lutomirski 2017-07-05 12:25 ` Peter Zijlstra 2017-07-05 12:25 ` Peter Zijlstra 2017-07-05 16:10 ` Andy Lutomirski 2017-07-05 16:10 ` Andy Lutomirski 2017-07-28 13:49 ` Peter Zijlstra 2017-07-28 13:49 ` Peter Zijlstra 2017-06-30 12:44 ` [PATCH v4 00/10] PCID and improved laziness Matt Fleming 2017-06-30 12:44 ` Matt Fleming 2017-07-11 11:32 ` Matt Fleming 2017-07-11 11:32 ` Matt Fleming 2017-07-11 15:00 ` Andy Lutomirski 2017-07-11 15:00 ` Andy Lutomirski 2017-07-13 19:36 ` Matt Fleming 2017-07-13 19:36 ` Matt Fleming 2017-07-05 8:56 ` Ingo Molnar 2017-07-05 8:56 ` Ingo Molnar 2017-07-05 16:53 ` Linus Torvalds 2017-07-05 16:53 ` Linus Torvalds 2017-07-17 9:57 ` Mel Gorman 2017-07-17 9:57 ` Mel Gorman 2017-07-17 15:06 ` Ingo Molnar 2017-07-17 15:06 ` Ingo Molnar 2017-07-17 15:56 ` Mel Gorman 2017-07-17 15:56 ` Mel Gorman [not found] ` <CALBSrqDW6pGjHxOmzfnkY_KoNeH6F=pTb8-tJ8r-zbu4prw9HQ@mail.gmail.com> 2017-09-12 19:32 ` Sai Praneeth Prakhya 2017-09-12 19:32 ` Sai Praneeth Prakhya 2017-09-12 19:45 ` Andy Lutomirski 2017-09-12 20:28 ` Prakhya, Sai Praneeth 2017-09-13 7:43 ` Ingo Molnar 2017-09-13 7:43 ` Ingo Molnar 2017-09-13 7:45 ` Ingo Molnar 2017-09-13 7:45 ` Ingo Molnar 2017-09-13 4:14 ` Sai Praneeth Prakhya 2017-09-13 4:14 ` Sai Praneeth Prakhya
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