From: Jarkko Sakkinen <jarkko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: linux-sgx@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages()
Date: Tue, 16 Mar 2021 14:50:04 +0200 [thread overview]
Message-ID: <YFCpfEaE8k3EzHbt@kernel.org> (raw)
In-Reply-To: <YE+1BPyK5SsizhEi@kernel.org>
On Mon, Mar 15, 2021 at 09:27:00PM +0200, Jarkko Sakkinen wrote:
> On Mon, Mar 15, 2021 at 09:06:29PM +0200, Jarkko Sakkinen wrote:
> > On Mon, Mar 15, 2021 at 08:32:13AM -0700, Dave Hansen wrote:
> > > On 3/13/21 8:01 AM, Jarkko Sakkinen wrote:
> > > > Replace the ad-hoc code with a sgx_free_epc_page(), in order to make sure
> > > > that all the relevant checks and book keeping is done, while freeing a
> > > > borrowed EPC page, and remove redundant code. EREMOVE inside
> > > > sgx_free_epc_page() does not change the semantics, as EREMOVE to an
> > > > uninitialize pages is a nop.
> > >
> > > ^ uninitialized
> > >
> > > I know this is a short patch, but this changelog still falls a bit short
> > > for me.
> > >
> > > Why is this patch a part of _this_ series? What *problem* does it
> > > solve, related to this series?
> >
> > I'm thinking of merging sgx_epc_section and sgx_numa_node. That's why I
> > kept it as part of the series.
> >
> > Also, in any case it's better to clean up duplicate functionality. The
> > code is essentially open coded implementation of sgx_free_epc_page()
> > without EREMOVE.
> >
> > > It would also be nice to remind me why the EREMOVE is redundant. Why
> > > didn't we need one before? What put the page in the uninitialized
> > > state? Is EREMOVE guaranteed to do nothing? How expensive is it?
> >
> > EREMOVE gets removed by KVM series from sgx_free_epc_page() anyway.
> >
> > Maybe should re-send this patch, or series, after KVM series is merged.
> > Then there is no explaining with EREMOVE, as sgx_free_epc_page() won't
> > contain it.
>
> Anyway, forgot to put the end statement: I'm cool with dropping this but
> I'll also send this right after KVM SGX series has landed as separate
> patch, if I drop this now.
HOLD ON :-)
I recalled why I added this patch to this patch set. I had a reason for
it.
It's because of the NUMA patch. I have duplicate all the NUMA changes
here if I don't refactor this somewhat redundant code out.
So, if I add a note about this to the commit message? IMHO, this is good
enough reason to carry the patch.
/Jarkko
next prev parent reply other threads:[~2021-03-16 12:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210313160119.1318533-1-jarkko@kernel.org>
2021-03-13 16:01 ` [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages() Jarkko Sakkinen
2021-03-15 15:32 ` Dave Hansen
2021-03-15 19:06 ` Jarkko Sakkinen
2021-03-15 19:27 ` Jarkko Sakkinen
2021-03-16 12:50 ` Jarkko Sakkinen [this message]
2021-03-13 16:01 ` [PATCH v4 2/3] x86/sgx: Replace section local dirty page lists with a global list Jarkko Sakkinen
2021-03-15 16:03 ` Dave Hansen
2021-03-15 19:14 ` Jarkko Sakkinen
2021-03-15 19:47 ` Dave Hansen
2021-03-13 16:01 ` [PATCH v4 3/3] x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page() Jarkko Sakkinen
2021-03-14 11:56 ` Jarkko Sakkinen
2021-03-15 16:35 ` Dave Hansen
2021-03-15 19:23 ` Jarkko Sakkinen
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