Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 20 Oct 2022 20:55:08 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Yu Zhao <yuzhao@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andi Kleen <ak@linux.intel.com>,
        Aneesh Kumar <aneesh.kumar@linux.ibm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Matthew Wilcox <willy@infradead.org>,
        Mel Gorman <mgorman@suse.de>,
        Michael Larabel <Michael@michaellarabel.com>,
        Michal Hocko <mhocko@kernel.org>,
        Mike Rapoport <rppt@kernel.org>, Tejun Heo <tj@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
        page-reclaim@google.com, Brian Geffon <bgeffon@google.com>,
        Jan Alexander Steffens <heftig@archlinux.org>,
        Oleksandr Natalenko <oleksandr@natalenko.name>,
        Steven Barrett <steven@liquorix.net>,
        Suleiman Souhlal <suleiman@google.com>,
        Daniel Byrne <djbyrne@mtu.edu>,
        Donald Carr <d@chaos-reins.com>,
        Holger =?iso-8859-1?Q?Hoffst=E4tte?= 
        <holger@applied-asynchrony.com>,
        Konstantin Kharlamov <Hi-Angel@yandex.ru>,
        Shuang Zhai <szhai2@cs.rochester.edu>,
        Sofia Trinh <sofia.trinh@edi.works>,
        Vaibhav Jain <vaibhav@linux.ibm.com>
Subject: Re: [PATCH v14 08/14] mm: multi-gen LRU: support page table walks
Message-ID: <Y1GZjPO+szk7X0wP@hirez.programming.kicks-ass.net>
References: <20220815071332.627393-1-yuzhao@google.com>
 <20220815071332.627393-9-yuzhao@google.com>
 <Y0go8wWtdcyH1+Ch@hirez.programming.kicks-ass.net>
 <CAOUHufa9+FTO3Pv-5jC-e3S5goPsUGu-5KcPVHa4bWb0X+d2ug@mail.gmail.com>
 <CAHk-=wj1rc2t5noMtVOgu8XXeTM4KiggEub9PdcexxeQrYPZvA@mail.gmail.com>
 <Y1FXpHdyvXjrjbLw@hirez.programming.kicks-ass.net>
 <CAHk-=whQchubuDpRGFabhmcZuzdt13OOF8wznXb+Dbi3GzBQhQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAHk-=whQchubuDpRGFabhmcZuzdt13OOF8wznXb+Dbi3GzBQhQ@mail.gmail.com>
Precedence: bulk

On Thu, Oct 20, 2022 at 10:35:28AM -0700, Linus Torvalds wrote:
> On Thu, Oct 20, 2022 at 7:14 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > So I've been sitting on these here patches (and never having time to
> > repost them), which is how I noticed in the first place:
> >
> >   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=x86/mm.pae
> 
> Well, that seems an improvement. I don't love how GUP_GET_PTE_LOW_HIGH
> now affects the PMD too, but if it's ok for all the three users, I
> guess it's ok. Maybe rename it now that it's not just the PTE?
> 
> That said, I reacted to that cmpxchg loop:
> 
>         } while (cmpxchg64(&pmdp->pmd, old.pmd, 0ULL) != old.pmd);
> 
> is this series just so old (but rebased) that it doesn't use "try_cmpxchg64()"?

Yep -- it's *that* old :-/ You're not in fact the first to point that
out.

I'll make time tomorrow to fix it up and respin and send out. This is as
good a time as any to get rid of carrying these patches myself.