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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Julien Grall <julien@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Anthony PERARD <anthony.perard@vates.tech>,
	Michal Orzel <michal.orzel@amd.com>,
	Oleksii Kurochko <oleksii.kurochko@gmail.com>
Subject: Re: [PATCH for-4.21] symbols: avoid emitting "end" symbols for data items
Date: Wed, 29 Oct 2025 20:13:22 +0100	[thread overview]
Message-ID: <aQJnUucAvn6Y2oc-@Mac.lan> (raw)
In-Reply-To: <6fdfd369-6c1e-48a5-8189-4999d566788a@suse.com>

On Wed, Oct 29, 2025 at 02:34:29PM +0100, Jan Beulich wrote:
> symbols-dummy.c and the generated .xen-syms.?.S may place their symbols in
> different sections: Like for all C files, -fdata-sections may be in effect
> there. As a result, besides moving these symbols may then also have
> different amounts of "end" symbols inserted between them. While the
> movement is likely not problematic, the change in table size is - linking
> passes 2 and 3 want no address (and hence no size) changes between them.
> 
> As, at least right now, the "end" symbols are useful only for code, limit
> their emission accordingly. When data symbols are emitted (i.e. when
> LIVEPATCH=y), this obviously also has a positive effect on overall table
> size (I'm seeing almost 600 entries going away in the build I'm looking
> at).
> 
> Fixes: d3b637fba31b ("symbols: arrange to know where functions end")
> Reported-by: Roger Pau Monné <roger.pau@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Thanks, this does seem to solve the issue I was seeing with clang +
LLD.

Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Tested-by: Roger Pau Monné <roger.pau@citrix.com>

With the commit message adjustment that you discussed with Andrew.

Roger.


  parent reply	other threads:[~2025-10-29 19:13 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-29 13:34 [PATCH for-4.21] symbols: avoid emitting "end" symbols for data items Jan Beulich
2025-10-29 15:13 ` Andrew Cooper
2025-10-29 15:24   ` Jan Beulich
2025-10-29 19:13 ` Roger Pau Monné [this message]
2025-10-30 16:02 ` Oleksii Kurochko

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