[gnome-system-monitor/wip/mallard-help: 53/68] Review memory-map-what help page
- From: Ekaterina Gerasimova <egerasimov src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gnome-system-monitor/wip/mallard-help: 53/68] Review memory-map-what help page
- Date: Tue, 4 Feb 2014 22:14:28 +0000 (UTC)
commit 5df1e7991ec528565218211199e3a192f343d1bf
Author: Ekaterina Gerasimova <kittykat3756 gmail com>
Date: Tue Jan 28 12:45:04 2014 +0000
Review memory-map-what help page
help/C/memory-map-what.page | 79 ++++++++++++++++++++++++------------------
1 files changed, 45 insertions(+), 34 deletions(-)
---
diff --git a/help/C/memory-map-what.page b/help/C/memory-map-what.page
index ebc4156..c808962 100644
--- a/help/C/memory-map-what.page
+++ b/help/C/memory-map-what.page
@@ -1,8 +1,9 @@
<page xmlns="http://projectmallard.org/1.0/"
type="topic" style="task"
id="memory-map-what">
+
<info>
- <revision version="0.2" pkgversion="3.11" date="2014-01-26" status="review"/>
+ <revision pkgversion="3.11" date="2014-01-28" status="candidate"/>
<link type="guide" xref="index" group="memory" />
<include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>
@@ -19,50 +20,60 @@
<years>2011, 2014</years>
</credit>
- <desc>The memory map of a process can help diagnose certain memory issues.</desc>
+ <desc>The memory map of a process can help diagnose certain memory
+ issues.</desc>
</info>
<title>What is a memory map?</title>
<comment>
<cite date="2011-06-18" href="mailto:philbull gmail com">Phil Bull</cite>
- <p>Difficult conceptual topic. Explain how to use memory maps to do whatever
- the hell you're supposed to use them for.</p>
+ <p>Difficult conceptual topic. Explain how to use memory maps to do
+ whatever the hell you're supposed to use them for.</p>
+ </comment>
+
+ <comment>
+ <cite date="2014-01-28" href="mailto:kittykat3756 gmail com">Kat</cite>
+ <p>TODO: check gui tags.</p>
</comment>
- <p><gui>Virtual memory</gui> is a representation of the combined <gui>physical
- memory</gui> and <link xref="mem-swap">swap space</link> in a system. It enables running processes
- to access <em>more</em> than the existing physical memory by <gui>mapping</gui>
- locations in physical memory to files on disk.</p>
+ <p><gui>Virtual memory</gui> is a representation of the combined
+ <gui>physical memory</gui> and <link xref="mem-swap">swap space</link> in a
+ system. It enables running processes to access <em>more</em> than the
+ existing physical memory by <gui>mapping</gui> locations in physical memory
+ to files on disk.</p>
- <p>When a program is launched, the system assigns it a unique process ID (PID)
- and its <em>instructions</em> and <em>data</em> are loaded into memory in
- <em>pages</em>. The page table of each process maps the correspondence between
- its pages in virtual memory and their location in physical memory. The
- <gui>memory map</gui> displays the total virtual memory use of the process, and
- can be used to determine the memory cost of running a single or multiple
- instances of the program, to ensure the use of the correct shared libraries, to
- see the results of adjusting various performance tuning parameters the program
- may have, or to diagnose issues such as memory leaks.</p>
+ <p>When a program is launched, the system assigns it a unique process ID
+ (PID) and its <em>instructions</em> and <em>data</em> are loaded into memory
+ in <em>pages</em>. The page table of each process maps the correspondence
+ between its pages in virtual memory and their location in physical memory.
+ The <gui>memory map</gui> displays the total virtual memory use of the
+ process, and can be used to determine the memory cost of running a single or
+ multiple instances of the program, to ensure the use of the correct shared
+ libraries, to see the results of adjusting various performance tuning
+ parameters the program may have, or to diagnose issues such as memory
+ leaks.</p>
- <p>If multiple copies of a program are running, the instructions (or <em>text</em>)
- of the program only need to be loaded once into physical memory. Each time a
- new instance of the program is launched (as a unique process with its own virtual
- memory pages), its page table maps the location of the text in virtual memory to
- those instructions in the original real memory location. In addition, any dynamic
- shared libraries used by the process appear as distinct in virtual memory, but
- are shared references to a single copy of the library's text segment in real
- memory. When accounting for the total memory use of a process, it is important
- to note that the cost of shared libraries loaded into memory can be spread
- across all processes currently using them.</p>
+ <p>If multiple copies of a program are running, the instructions (or
+ <em>text</em>) of the program only need to be loaded once into physical
+ memory. Each time a new instance of the program is launched (as a unique
+ process with its own virtual memory pages), its page table maps the location
+ of the text in virtual memory to those instructions in the original real
+ memory location. In addition, any dynamic shared libraries used by the
+ process appear as distinct in virtual memory, but are shared references to a
+ single copy of the library's text segment in real memory. When accounting for
+ the total memory use of a process, it is important to note that the cost of
+ shared libraries loaded into memory can be spread across all processes
+ currently using them.</p>
<p>When the system needs more pages of memory than are available, some of the
- existing pages will be <em>paged out</em> or written to the <gui>swap space</gui>.
- Text pages are flagged read-execute in memory and don't need to be written to
- swap since they can be re-loaded from their original location on disk. Data
- pages have read-write permissions, and if modified when in memory, they are
- labeled <em>dirty</em>, and when designated for swapping, must be paged out.
- When a page in swap space is required by a running process, it needs to be
- swapped back in before use, perhaps causing another page to be paged out.</p>
+ existing pages will be <em>paged out</em> or written to the <gui>swap
+ space</gui>. Text pages are flagged read-execute in memory and don't need to
+ be written to swap since they can be re-loaded from their original location
+ on disk. Data pages have read-write permissions, and if modified when in
+ memory, they are labeled <em>dirty</em>, and when designated for swapping,
+ must be paged out. When a page in swap space is required by a running
+ process, it needs to be swapped back in before use, perhaps causing another
+ page to be paged out.</p>
</page>
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