[PATCH -perfbook 4/6] defer/rcuintro: More tweaks for Listings 9.13 and 9.14

To make text parts in those floating listings easier to distinguish
from those of main contents, fine tune their appearance by:

   1) Use \footnotesize,
   2) Widen margins, and
   3) Tweak vertical spaces above/below framed code snippets.

Signed-off-by: Akira Yokosawa <[email protected]>
---
 defer/rcuintro.tex | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/defer/rcuintro.tex b/defer/rcuintro.tex
index 596f138f..6997378b 100644
--- a/defer/rcuintro.tex
+++ b/defer/rcuintro.tex
@@ -2,6 +2,10 @@
 % mainfile: ../perfbook.tex
 % SPDX-License-Identifier: CC-BY-SA-3.0
 
+\newcommand{\adjvspaceabove}{\vspace*{2pt}}
+\newcommand{\adjvspacebelow}{\vspace*{-1pt}}
+\newcommand{\adjvspacebottom}{\vspace*{-2pt}}
+
 \subsection{Introduction to RCU}
 \label{sec:defer:Introduction to RCU}
 
@@ -69,26 +73,29 @@ can be implemented with a single load instruction, exactly the instruction
 that would normally be used in single-threaded code.
 
 \begin{listing}[tb]
-\small
-\fvset{numbers=left,numbersep=5pt,fontsize=\scriptsize,frame=single,xleftmargin=15pt,xrightmargin=5pt}
+\begin{adjustwidth}{10pt}{5pt}
+\footnotesize
+\fvset{numbers=left,numbersep=5pt,fontsize=\scriptsize,frame=single,xrightmargin=5pt}
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny A\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = gp;
  do_something_with(p->a);
  do_something_with(p->b);
 \end{Verbatim}
-}
+}\adjvspacebelow
 Might be transformed to:
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny B\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = gp;
  do_something_with(p->a);
  p = gp;
  do_something_with(p->b);
 \end{Verbatim}
-}
+}\adjvspacebelow
 The compiler assumes normal variables do not spontaneously change,
 \co{do_something_with()} might use many machine registers, and this
 transformation reduces register pressure.
@@ -97,38 +104,43 @@ transformed code, the values of \co{p->a} and \co{p->b} will be mismatched.
 Prevent this by using \co{rcu_dereference()} as follows:
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny C\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = rcu_dereference(gp);
  do_something_with(p->a);
  do_something_with(p->b);
 \end{Verbatim}
-}
+}\adjvspacebelow
+\end{adjustwidth}\adjvspacebottom
 \caption{Compilers Can Reload Values}
 \label{lst:defer:Compilers Can Reload Values}
 \end{listing}
 
 \begin{listing}[tb]
-\small
-\fvset{numbers=left,numbersep=5pt,fontsize=\scriptsize,frame=single,xleftmargin=15pt,xrightmargin=5pt}
+\begin{adjustwidth}{10pt}{5pt}
+\footnotesize
+\fvset{numbers=left,numbersep=5pt,fontsize=\scriptsize,frame=single,xrightmargin=5pt}
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny A\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = malloc(sizeof(*p));
  p->a = compute_value();
  p->b = 42;
  gp = p;
 \end{Verbatim}
-}
+}\adjvspacebelow
 Might be transformed to:
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny B\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = malloc(sizeof(*p));
  gp = p;
  p->a = compute_value();
  p->b = 42;
 \end{Verbatim}
-}
+}\adjvspacebelow
 The compiler assumes normal variables are not concurrently accessed,
 and thus that the order of stores does not matter.
 If \co{compute_value()} was inlined, this transformation might produce
@@ -139,13 +151,15 @@ garbage in \co{p->a} and \co{p->b}.
 Prevent this by using \co{rcu_assign_pointer()} as follows:
 {\renewcommand{\theFancyVerbLine}{%
   {\rmfamily\tiny C\arabic{FancyVerbLine}}}
+\adjvspaceabove%
 \begin{Verbatim}
  p = malloc(sizeof(*p));
  p->a = compute_value();
  p->b = 42;
  rcu_assign_pointer(gp, p);
 \end{Verbatim}
-}
+}\adjvspacebelow
+\end{adjustwidth}\adjvspacebottom
 \caption{Compilers Can Reorder Accesses}
 \label{lst:defer:Compilers Can Reorder Accesses}
 \end{listing}
-- 
2.43.0