From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>, Christoph Hellwig <hch@lst.de>,
Chuck Lever III <chuck.lever@oracle.com>,
Mark Hemment <markhemm@googlemail.com>,
Patrice CHOTARD <patrice.chotard@foss.st.com>,
Mikulas Patocka <mpatocka@redhat.com>,
Lukas Czerner <lczerner@redhat.com>,
"Darrick J. Wong" <djwong@kernel.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Borislav Petkov <bp@alien8.de>,
linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
viro@zeniv.linux.org.uk
Subject: Re: [PATCH] tmpfs: fix regressions from wider use of ZERO_PAGE
Date: Wed, 13 Apr 2022 18:41:28 +0200 [thread overview]
Message-ID: <20220413164128.GD31487@lst.de> (raw)
In-Reply-To: <20220412162221.7c55379548017bab61ea5103@linux-foundation.org>
On Tue, Apr 12, 2022 at 04:22:21PM -0700, Andrew Morton wrote:
> On Fri, 8 Apr 2022 23:08:29 -0700 (PDT) Hugh Dickins <hughd@google.com> wrote:
>
> > >
> > > Either way I'd rather do this optimization in iov_iter_zero rather
> > > than hiding it in tmpfs.
> >
> > Let's see what others say. I think we would all prefer clear_user() to be
> > enhanced, and hack around it neither here in tmpfs nor in iov_iter_zero().
> > But that careful work won't get done by magic, nor by me.
> >
> > And iov_iter_zero() has to deal with a wider range of possibilities,
> > when pulling in cache lines of ZERO_PAGE(0) will be less advantageous,
> > than in tmpfs doing a large dd - the case I'm aiming not to regress here
> > (tmpfs has been copying ZERO_PAGE(0) like this for years).
>
> We do need something to get 5.18 fixed. Christoph, do you think we
> should proceed with this patch for 5.18?
Well, let's queue it up then.
prev parent reply other threads:[~2022-04-13 16:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-08 20:38 [PATCH] tmpfs: fix regressions from wider use of ZERO_PAGE Hugh Dickins
2022-04-09 5:06 ` Christoph Hellwig
2022-04-09 6:08 ` Hugh Dickins
2022-04-12 4:57 ` making x86 clear_user not suck, was " Christoph Hellwig
2022-04-13 18:06 ` Matthew Wilcox
2022-04-12 23:22 ` Andrew Morton
2022-04-13 16:41 ` Christoph Hellwig [this message]
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