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From: Yang Shi <shy828301@gmail.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>,
	Matthew Wilcox <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Linux MM <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Miaohe Lin <linmiaohe@huawei.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@suse.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH] mm,shmem: Fix a typo in shmem_swapin_page()
Date: Mon, 9 Aug 2021 18:11:44 -0700	[thread overview]
Message-ID: <CAHbLzkrB7FRqgFKErFP0BEjgWhnOpwjZCk5qHHxkkUYPFuT6aw@mail.gmail.com> (raw)
In-Reply-To: <87k0ku89ql.fsf@yhuang6-desk2.ccr.corp.intel.com>

On Mon, Aug 9, 2021 at 4:43 PM Huang, Ying <ying.huang@intel.com> wrote:
>
> Yang Shi <shy828301@gmail.com> writes:
>
> > On Fri, Aug 6, 2021 at 1:37 PM Yang Shi <shy828301@gmail.com> wrote:
> >>
> >> On Thu, Aug 5, 2021 at 11:01 PM Hugh Dickins <hughd@google.com> wrote:
> >> >
> >> > On Thu, 5 Aug 2021, Yang Shi wrote:
> >> > > On Tue, Aug 3, 2021 at 10:34 PM Hugh Dickins <hughd@google.com> wrote:
> >> > > >
> >> > > > I've never seen the swapoff race claimed by Miaohe, and don't expect to;
> >> > > > but he's probably right, given the current code.  I just dislike adding
> >> > > > unnecessary complexity, and siting it in the wrong place (mm/shmem.c).
> >> > > >
> >> > > > Yang, is it possible that 5.1 commit 8fd2e0b505d1 ("mm: swap: check if
> >> > > > swap backing device is congested or not") was actually developed and
> >> > > > measured on 4.1 or earlier, which still had blk_set_queue_congested()?
> >> > >
> >> > > I forgot the exact version, but definitely not 4.1 or earlier. Maybe
> >> > > 4.19 or earlier. I'm not familiar with how block layer detect
> >> > > congestion, if the logic was changed, hence the optimization doesn't
> >> > > stand anymore nowadays, I'm totally fine to remove it.
> >> >
> >> > You drove me back to look more closely.  blk_set_queue_congested()
> >> > vanished from include/linux/blkdev.h in 4.2, but blk_set_congested()
> >> > appeared then in block/blk-core.c to replace it.  blk_set_congested()
> >> > vanished (along with all references to "congested" in blk-core.c) in
> >> > 5.0, then your commit (most probably tested on 4.19) went into 5.1 -
> >> > just after it had become redundant!
> >> >
> >> > Thanks, yes, let's revert that and Miaohe's and Huang's, later on.
> >>
> >> It should be easier to revert Huang Ying's , then Miaohe's, then mine.
> >
> > Hi Ying,
> >
> > I just prepared the reverts since I need to revert yours and Miaohe's
> > in order to revert my problematic commit.
>
> If your original commit will be reverted, then mine and Miaohe's can be
> reverted from the race condition point of view.

Yes, this is exactly what I did.

>
> Although I still think it's better to call get/put_swap_device() in
> shmem_swapin_page(), that can be discussed with another patch.

Any additional change could be based off the reverts.

>
> Best Regards,
> Huang, Ying

  reply	other threads:[~2021-08-10  1:12 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23  8:00 Huang Ying
2021-07-23 11:10 ` David Hildenbrand
2021-07-23 20:23 ` Hugh Dickins
2021-07-23 21:53   ` Matthew Wilcox
2021-08-03  8:14     ` Huang, Ying
2021-08-03 12:01       ` Matthew Wilcox
2021-08-04  5:34         ` Hugh Dickins
2021-08-04  9:04           ` Huang, Ying
2021-08-05 23:08           ` Yang Shi
2021-08-06  6:01             ` Hugh Dickins
2021-08-06 20:37               ` Yang Shi
2021-08-09 21:26                 ` Yang Shi
2021-08-09 23:43                   ` Huang, Ying
2021-08-10  1:11                     ` Yang Shi [this message]
2021-08-04  9:01         ` Huang, Ying
2021-07-28 13:03   ` huang ying
2021-08-03  8:06     ` Huang, Ying
2021-08-03 11:59       ` Matthew Wilcox
2021-08-04  4:28       ` Hugh Dickins
2021-08-04  6:42     ` Hugh Dickins
2021-08-04  8:59       ` Huang, Ying

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