From: Andrew Morton <akpm@linux-foundation.org>
To: Hugh Dickins <hughd@google.com>
Cc: 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: Tue, 12 Apr 2022 16:22:21 -0700 [thread overview]
Message-ID: <20220412162221.7c55379548017bab61ea5103@linux-foundation.org> (raw)
In-Reply-To: <f73cfd56-35d2-53a3-3a59-4ff9495d7d34@google.com>
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?
next prev parent reply other threads:[~2022-04-12 23:39 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 [this message]
2022-04-13 16:41 ` Christoph Hellwig
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