linux-kernel - Re: [PATCH v3 31/35] lib: add memory allocations report in show

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Message-ID: <20240215181648.67170ed5@gandalf.local.home>
Date: Thu, 15 Feb 2024 18:16:48 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Kent Overstreet <kent.overstreet@...ux.dev>
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Subject: Re: [PATCH v3 31/35] lib: add memory allocations report in
 show_mem()

On Thu, 15 Feb 2024 18:07:42 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:

>    text         data            bss     dec             hex filename
> 29161847        18352730        5619716 53134293        32ac3d5 vmlinux.orig
> 29162286        18382638        5595140 53140064        32ada60 vmlinux.memtag-off		(+5771)
> 29230868        18887662        5275652 53394182        32ebb06 vmlinux.memtag			(+259889)
> 29230746        18887662        5275652 53394060        32eba8c vmlinux.memtag-default-on	(+259767) dropped?
> 29276214        18946374        5177348 53399936        32ed180 vmlinux.memtag-debug		(+265643)

If you plan on running this in production, and this increases the size of
the text by 68k, have you measured the I$ pressure that this may induce?
That is, what is the full overhead of having this enabled, as it could
cause more instruction cache misses?

I wonder if there has been measurements of it off. That is, having this
configured in but default off still increases the text size by 68k. That
can't be good on the instruction cache.

-- Steve