From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id 55870831FE for ; Tue, 9 May 2017 18:55:14 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id d127so11492093pga.11 for ; Tue, 09 May 2017 15:55:14 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.136]) by mx.google.com with ESMTPS id u22si199415plk.91.2017.05.09.15.55.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 May 2017 15:55:13 -0700 (PDT) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9070E20303 for ; Tue, 9 May 2017 22:55:12 +0000 (UTC) Received: from mail-ua0-f170.google.com (mail-ua0-f170.google.com [209.85.217.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 634E820268 for ; Tue, 9 May 2017 22:55:10 +0000 (UTC) Received: by mail-ua0-f170.google.com with SMTP id g49so17230289uaa.1 for ; Tue, 09 May 2017 15:55:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <983c5ee661d8fe8a70c596c4e77076d11ce3f80a.1494160201.git.luto@kernel.org> From: Andy Lutomirski Date: Tue, 9 May 2017 15:54:49 -0700 Message-ID: Subject: Re: [RFC 03/10] x86/mm: Make the batched unmap TLB flush API more generic Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Andy Lutomirski , X86 ML , "linux-kernel@vger.kernel.org" , Borislav Petkov , Linus Torvalds , Andrew Morton , Mel Gorman , "linux-mm@kvack.org" , Rik van Riel , Nadav Amit , Michal Hocko , Sasha Levin On Tue, May 9, 2017 at 10:13 AM, Dave Hansen wrote: > On 05/09/2017 06:02 AM, Andy Lutomirski wrote: >> On Mon, May 8, 2017 at 8:34 AM, Dave Hansen wrote: >>> On 05/07/2017 05:38 AM, Andy Lutomirski wrote: >>>> diff --git a/mm/rmap.c b/mm/rmap.c >>>> index f6838015810f..2e568c82f477 100644 >>>> --- a/mm/rmap.c >>>> +++ b/mm/rmap.c >>>> @@ -579,25 +579,12 @@ void page_unlock_anon_vma_read(struct anon_vma *anon_vma) >>>> void try_to_unmap_flush(void) >>>> { >>>> struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; >>>> - int cpu; >>>> >>>> if (!tlb_ubc->flush_required) >>>> return; >>>> >>>> - cpu = get_cpu(); >>>> - >>>> - if (cpumask_test_cpu(cpu, &tlb_ubc->cpumask)) { >>>> - count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL); >>>> - local_flush_tlb(); >>>> - trace_tlb_flush(TLB_LOCAL_SHOOTDOWN, TLB_FLUSH_ALL); >>>> - } >>>> - >>>> - if (cpumask_any_but(&tlb_ubc->cpumask, cpu) < nr_cpu_ids) >>>> - flush_tlb_others(&tlb_ubc->cpumask, NULL, 0, TLB_FLUSH_ALL); >>>> - cpumask_clear(&tlb_ubc->cpumask); >>>> tlb_ubc->flush_required = false; >>>> tlb_ubc->writable = false; >>>> - put_cpu(); >>>> } >>>> >>>> /* Flush iff there are potentially writable TLB entries that can race with IO */ >>>> @@ -613,7 +600,7 @@ static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) >>>> { >>>> struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; >>>> >>>> - cpumask_or(&tlb_ubc->cpumask, &tlb_ubc->cpumask, mm_cpumask(mm)); >>>> + arch_tlbbatch_add_mm(&tlb_ubc->arch, mm); >>>> tlb_ubc->flush_required = true; >>>> >>>> /* >>> >>> Looking at this patch in isolation, how can this be safe? It removes >>> TLB flushes from the generic code. Do other patches in the series fix >>> this up? >> >> Hmm? Unless I totally screwed this up, this patch just moves the >> flushes around -- it shouldn't remove any flushes. > > This takes a flush out of try_to_unmap_flush(). It adds code for > arch_tlbbatch_flush(), but not *calls* to arch_tlbbatch_flush() that I > can see. > > I actually don't see _any_ in the whole series in a quick grepping. Am > I just missing them? Oops! I must have stared at that function for so long that I started seeing the invisible call. I'll fix that. -- 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: email@kvack.org