Date: Tue, 22 Oct 2013 14:55:05 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r256908 - user/glebius/course/05.memory Message-ID: <201310221455.r9MEt5Me056668@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: glebius Date: Tue Oct 22 14:55:04 2013 New Revision: 256908 URL: http://svnweb.freebsd.org/changeset/base/256908 Log: More on memory. Modified: user/glebius/course/05.memory/lection.tex Modified: user/glebius/course/05.memory/lection.tex ============================================================================== --- user/glebius/course/05.memory/lection.tex Tue Oct 22 14:50:28 2013 (r256907) +++ user/glebius/course/05.memory/lection.tex Tue Oct 22 14:55:04 2013 (r256908) @@ -16,12 +16,26 @@ \usetikzlibrary{arrows} \usetikzlibrary{decorations.text} \usetikzlibrary{chains} +\usetikzlibrary{scopes} \usetikzlibrary{calc} \input{../course.tex} \title{Memory management in FreeBSD} +\tikzset { + entry/.style={draw, thick, on chain, text width=.25\paperwidth, + align=center}, + large/.style={entry, minimum height=.15\paperheight}, + noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, + nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, + page/.style={draw, thick, node distance=3mm}, + vmmap/.style={draw, thick, rounded corners}, + vmentry/.style={draw, thick, rounded corners}, + vmobject/.style={draw, thick, rounded corners, text width=7ex }, + pointer/.style={->, thick, rounded corners}, +} + \begin{document} \begin{frame} @@ -33,13 +47,6 @@ \frametitle{Process (static) address space} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=kernel, nolarge] { kernel }; \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; @@ -86,13 +93,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; \node [name=unmap, nolarge] { not mapped memory }; @@ -115,13 +115,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large, minimum height=.20\paperheight] { stack }; \node [name=unmap, nolarge, minimum height=.10\paperheight] @@ -149,13 +142,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; \node [name=unmap, nolarge] { not mapped memory }; @@ -175,13 +161,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; \node [name=unmap, nolarge, minimum height=.10\paperheight] @@ -209,13 +188,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; \node [name=unmap, nolarge] { not mapped memory }; @@ -235,13 +207,6 @@ Try this out: \begin{column}{.4\paperwidth} \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] - \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, - large/.style={entry, minimum height=.15\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, - } \node [name=argv, entry] { argv, envp }; \node [name=stack, large] { stack }; \node [name=unmap1, nolarge, minimum height=.05\paperheight] @@ -269,11 +234,7 @@ Try this out: \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, large/.style={entry, minimum height=.1\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, } \node [name=argv, entry] { argv, envp }; \node [name=stack, entry] { stack }; @@ -317,11 +278,7 @@ Try this out: \begin{figure} \begin{tikzpicture}[start chain=going below, node distance=0mm] \tikzset { - entry/.style={draw, thick, on chain, text width=.25\paperwidth, - align=center}, large/.style={entry, minimum height=.1\paperheight}, - noentry/.style={entry, fill=gray, shading=axis, shading angle=45}, - nolarge/.style={large, fill=gray, shading=axis, shading angle=45}, } \node [name=argv, entry] { argv, envp }; \node [name=stack, entry] { stack }; @@ -385,11 +342,11 @@ Try this out: }; \node [name=mark, node distance=5mm, above left=of entry1] {}; - \draw [->, thick, rounded corners] (vmmap.two east) -- ++(5mm,0) + \draw [pointer] (vmmap.two east) -- ++(5mm,0) |- (mark.center) |- (entry1.one west); \draw [->, thick] (entry1.two east) to [out=0, in=180] (entry2.one west); - \draw [->, thick, rounded corners] (entry2.two east) -- + \draw [pointer] (entry2.two east) -- ++(5mm,0) -- ++(0,-1cm); \end{tikzpicture} \end{figure} @@ -401,25 +358,24 @@ Try this out: \frametitle{A VM map entry is backed by an object} \begin{figure} \begin{tikzpicture} - \tikzset { - page/.style={draw, thick, node distance=3mm}, - } \node [name=entry, struct, rectangle split parts=4] { \textbf{struct vm\_map\_entry} \nodepart{two} \ldots \nodepart{three} struct vm\_object *object \nodepart{four} \ldots }; - \node [name=object, struct, right=of entry, rectangle split parts=3] { + \node [name=object, struct, right=of entry, rectangle split parts=5] { \textbf{struct vm\_object} - \nodepart{two} struct vm\_radix head - \nodepart{three} union *pager + \nodepart{two} \ldots + \nodepart{four} union *pager + \nodepart{three} struct vm\_radix rtree + \nodepart{five} \ldots }; \draw [->, thick] (entry.three east) to [out=0, in=180] (object.one west); \node [name=page1, page, below=of object] { vm\_page }; - \draw [->, thick, rounded corners] (object.two east) -- ++(1cm,0) + \draw [->, thick, rounded corners] (object.three east) -- ++(1cm,0) |- (page1.east); \node [name=page2, page, below right=of page1] { vm\_page }; @@ -445,4 +401,255 @@ Try this out: \end{frame} +\FootReferences{}{sys/vm/vm\_page.h, sys/vm/vm\_page.c} +\begin{frame} +\frametitle{VM page} + \begin{itemize} + \item{Small structure describing one resident physical page} + \item{All vm\_page structs are allocated at boot time} + \item{A page belongs to one object} + \end{itemize} +\end{frame} + + +\FootReferences{}{sys/vm/vm\_pager.h, sys/vm/vm\_pager.c} +\begin{frame} +\frametitle{VM objects' pager} +\begin{columns} +\begin{column}{.5\paperwidth} + \begin{itemize} + \item{Object serves as cache of memory page} + \item{Pager implements particular cache in/cache out semantics} + \end{itemize} +\end{column} +\begin{column}{.5\paperwidth} + \begin{figure} + \begin{tikzpicture} + \node [struct, rectangle split parts=7] { + \textbf{struct pagerops} + \nodepart{two} pgo\_init\_t *pgo\_init + \nodepart{three} pgo\_alloc\_t *pgo\_alloc + \nodepart{four} pgo\_dealloc\_t *pgo\_dealloc + \nodepart{five} pgo\_getpages\_t *pgo\_getpages + \nodepart{six} pgo\_putpages\_t *pgo\_putpages + \nodepart{seven} pgo\_haspage\_t *pgo\_haspage + }; + \end{tikzpicture} + \end{figure} +\end{column} +\end{columns} +\end{frame} + + +\FootReferences{}{sys/vm/vm\_object.h, sys/vm/vm\_object.c, + sys/vm/default\_pager.c, sys/vm/swap\_pager.c} +\begin{frame} +\frametitle{Anonymous object} +\begin{columns} +\begin{column}{.5\paperwidth} + \begin{figure} + \begin{tikzpicture} + \node [name=object, struct, rectangle split parts=5] { + \textbf{struct vm\_object} + \only<1> { \nodepart{two} \textit{uses default pager} } + \only<2,3> { \nodepart{two} \textit{{\color{red}uses swap pager}}} + \nodepart{three} \ldots + \nodepart{four} struct vm\_radix rtree + \nodepart{five} \ldots + }; + \node [name=page1, page, below right=of object] {vm\_page}; + \draw [pointer] (object.five east) -| (page1.north); + \only<1,2> { + \node [name=page2, page, node distance=0, below=of page1] {vm\_page}; + \node [name=page3, page, node distance=0, below=of page2] {vm\_page}; + } + \only<2> { + \node [name=swap, draw, rounded corners, fill=gray, shading=axis, + left=of page3, xshift=-2em] + {swap partition}; + \node [name=ell, draw, thick, color=red, ellipse, + minimum width=12ex, minimum height=4em] at (page2.south) {}; + \draw [->, thick, color=red] + (node cs:name=ell, angle=235) to [out=235, in=315] + node [above] { swap out } (swap.south); + } + \end{tikzpicture} + \end{figure} +\end{column} +\begin{column}{.4\paperwidth} + \begin{itemize} + \item{Anonymous object usually backs vm\_map\_entry made by sbrk(), + or mmap(MAP\_ANON), or stack} + \item{Default pager is a nop} + \onslide<2-> { + \item{In case of memory pressure default pages is changed to swap pager} + } + \onslide<3-> { + \item{Object remains with swap pager forever} + } + \end{itemize} +\end{column} +\end{columns} +\end{frame} + + +\FootReferences{}{sys/vm/vm\_object.h, sys/vm/vm\_object.c, + sys/vm/vnode\_pager.c} +\begin{frame} +\frametitle{Vnode backed object} +\begin{columns} +\begin{column}{.5\paperwidth} + \begin{figure} + \begin{tikzpicture} + \node [name=object, struct, rectangle split parts=6] { + \textbf{struct vm\_object} + \nodepart{two} uses vnode pager + \nodepart{three} \ldots + \nodepart{four} void *handle + \nodepart{five} struct vm\_radix rtree + \nodepart{six} \ldots + }; + \node [name=vnode, struct, below=of object.south west, anchor=west, + rectangle split parts=1] { + \textbf{struct vnode} + }; + \draw [->, thick] (object.four west) to [out=180, in=180] + (vnode.one west); + \node [name=file, draw, rounded corners, fill=gray, shading=axis, + below=of vnode] {a file}; + \draw [->, thick] (vnode) -- (file); + \node [name=page1, page, below right=of object] {vm\_page}; + \node [name=page2, page, node distance=0, below=of page1] {vm\_page}; + \node [name=page3, page, node distance=0, below=of page2] {vm\_page}; + \draw [pointer] (object.five east) -| (page1.north); + \only<2> { + \node [name=page4, page, color=red, node distance=0, below=of page3] + {vm\_page}; + \draw [->, thick, color=red] (file.east) to [out=0, in=270] + node [pos=.3, above, sloped] { page in } (page4.south); + } + \only<3> { + \node [name=ell, draw, thick, color=red, ellipse, + minimum width=12ex, minimum height=2em] at (page2) {}; + \draw [->, thick, color=red] (ell.west) to [out=180, in=0] + node [below, sloped] { page out } (file.east); + } + \end{tikzpicture} + \end{figure} +\end{column} +\begin{column}{.4\paperwidth} + \begin{itemize} + \item{Vnode object backs vm\_map\_entry made for program text, initialized + data, dynamic library text/data or result of mmap() on a file} + \onslide<2-> { + \item{Page fault brings a page from the file into memory} + } + \onslide<3-> { + \item{If mapping is {\color{red}writable and shared}, + dirty pages are written back to the file} + } + \end{itemize} +\end{column} +\end{columns} +\end{frame} + + +\FootReferences{}{sys/vm/vm\_object.h, sys/vm/vm\_object.c} +\begin{frame} +\frametitle<1>{Private mappings} +\frametitle<2>{Private mappings: a process fork(2)s} +\frametitle<3>{Private mappings: child modifies a page} +\frametitle<4-5>{Private mappings: shadow chains can grow hairy} +\frametitle<6-7>{Private mappings: shadow chain split} +\frametitle<8-9>{Private mappings: shadow chain collapse} +\begin{figure} +\begin{tikzpicture}[node distance=2mm] + \node [name=procA, vmmap] { process A }; + \node [name=entA, vmentry, below right=of procA] { vm\_map\_entry }; + \draw [pointer] (procA.south) |- (entA.west); + + \node [name=obj, vmobject, below right=2mm and .4\paperwidth of entA] + { vnode object }; + \draw [pointer] (entA.east) -| (obj.north); + \node [name=page1, page, below=of obj] {page 1}; + \draw [pointer] (obj) -- (page1); + \node [name=page2, page, node distance=0, below=of page1] {page 2}; + \node [name=page3, page, node distance=0, below=of page2] {page 3}; + + \onslide<2-7> { + \node [name=procB, vmmap, below=.2\paperheight of procA] { process B }; + \node [name=entB, vmentry, below right=of procB] { vm\_map\_entry }; + \draw [pointer] (procB.south) |- (entB.west); + } + + \only<2> { + \draw [pointer] (entB.north) |- (node cs:name=obj, angle=200); + } + + \onslide<3-> { + \node [name=shadow, vmobject, above right=2mm and 10mm of entB] + { shadow object }; + \draw [pointer] (shadow.east) to [out=0, in=180] (obj.west); + \node [name=pageB1, page, below=of shadow] {page 1}; + \draw [pointer] (shadow) -- (pageB1); + } + \onslide<3-7> { + \draw [pointer] (entB.north) |- (shadow.west); + } + + \onslide<4-> { + \node [name=procC, vmmap, below=.2\paperheight of procB] { process C }; + \node [name=entC, vmentry, below right=of procC] { vm\_map\_entry }; + \draw [pointer] (procC.south) |- (entC.west); + } + + \only<4> { + \node [name=mark, above right=of entC] {} ; + \draw [pointer] (entC.north) + .. controls +(0,10mm) and (mark) .. (shadow.south west); + } + + \onslide<5-8> { + \node [name=shadowC, vmobject, below=.2\paperheight of shadow] + { shadow object }; + \draw [pointer] (entC.north) |- (shadowC.west); + } + \onslide<5,8> { + \node [name=pageC2, page, below=of shadowC] {page 2}; + \draw [pointer] (shadowC) -- (pageC2); + } + \onslide<5,6,8> { + \draw [pointer] (shadowC.north west) + to [out=135, in=225] (shadow.south west); + } + + \onslide<6-7> { + \node [name=pageC1, page, below=of shadowC] {{\color{red}page 1}}; + \draw [pointer] (shadowC) -- (pageC1); + } + + \onslide<7> { + \draw [pointer, color=red] (shadowC.east) + to [out=0, in=225] (obj.south west); + } + + \onslide<8> { + \node [name=procB, vmmap, below=.2\paperheight of procA, dotted] + { process B }; + \node [name=entB, vmentry, below right=of procB, dotted] + { vm\_map\_entry }; + \draw [pointer, dotted] (procB.south) |- (entB.west); + \draw [pointer, dotted] (entB.north) |- (shadow.west); + } + + \onslide<9> { + \draw [pointer, color=red] (entC.north) to [out=90, in=180] (shadow.west); + \node [name=pageB2, page, node distance=0, below=of pageB1] + {{\color{red}page 2}}; + } + +\end{tikzpicture} +\end{figure} +\end{frame} + \end{document}
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201310221455.r9MEt5Me056668>