Merge remote-tracking branch 'fp/master'

3 files changed, 113 insertions, 0 deletions

diff --git a/hurd/debugging/rpctrace.mdwn b/hurd/debugging/rpctrace.mdwn
index f7136056..fd24f081 100644
--- a/hurd/debugging/rpctrace.mdwn
+++ b/hurd/debugging/rpctrace.mdwn
@@ -52,6 +52,43 @@ See `rpctrace --help` about how to use it.
         <antrik> note that there is a number of known bugs in rpctrace, for which zhengda has sent patches... though I haven't reviewed all of them I think
         <antrik> there are some nasty Mach operations that are really hard to proxy -- but I don't think the auth mechanism needs any of these...
 
+* IRC, freenode, #hurd, 2011-11-04
+
+    [[!taglink open_issue_documentation]]
+
+        <mcsim> hello. Are there any documentation about understanding output
+          of rpctrace?
+        <braunr> no
+        <braunr> you should read the source code, best doc available
+        <braunr> if you have too many numbers and almost no symbolc names,
+          you're lacking rpc definition lists
+        <braunr> check that the gnumach-common package is installed, as it
+          provides the gnumach definitions
+        <braunr> (the glibc ones are almost always available)
+        <braunr> with those two, you should be fine for the beginning
+        <mcsim> gnumach-common is installed. And what is the name for glibc
+          package for gnumach definitions.
+        <mcsim> Also I'm using libraries specified by LD_LIBRARY_PATH. Does it
+          make influence on absence of symbolic names?
+        <braunr> no
+        <braunr> rpctrace --help
+        <braunr> see the --rpc-list=FILE option
+        <braunr> the default lists are in /usr/share/msgids/, with the .msgids
+          extension
+        <braunr> $ dpkg -S msgids
+        <braunr> gnumach-common: /usr/share/msgids/gnumach.msgids
+        <braunr> hurd: /usr/share/msgids/hurd.msgids
+        <braunr> ok, glibc has none, it's the hurd
+        <braunr> for more details about the output, read the source code
+        <braunr> it shouldn't be that hard to grasp
+        <mcsim> -I /usr/share/msgids helped
+        <mcsim> thank you
+        <braunr> it shouldn't have, it's the default path
+        <mcsim> but symbolic names appeared
+        <braunr> well, that's weird :)
+        <pinotree> braunr: the output of rpctrace --help should tell the
+          default dir for msgids
+
 
 # See Also
 
diff --git a/hurd/translator/tmpfs/tmpfs_vs_defpager.mdwn b/hurd/translator/tmpfs/tmpfs_vs_defpager.mdwn
index a9317c21..5228515f 100644
--- a/hurd/translator/tmpfs/tmpfs_vs_defpager.mdwn
+++ b/hurd/translator/tmpfs/tmpfs_vs_defpager.mdwn
@@ -233,3 +233,40 @@ See also: [[open_issues/resource_management_problems/pagers]].
       I have never looked at it.
 
 [[open_issues/mach-defpager_vs_defpager]].
+
+
+# IRC, freenode, #hurd, 2011-11-08
+
+    <mcsim> who else uses defpager besides tmpfs and kernel?
+    <braunr> normally, nothing directly
+    <mcsim> than why tmpfs should use defpager?
+    <braunr> it's its backend
+    <braunr> backign store rather
+    <braunr> the backing store of most file systems are partitions
+    <braunr> tmpfs has none, it uses the swap space
+    <mcsim> if we allocate memory for tmpfs using vm_allocate, will it be able
+      to use swap partition?
+    <braunr> it should
+    <braunr> vm_allocate just maps anonymous memory
+    <braunr> anonymous memory uses swap space as its backing store too
+    <braunr> but be aware that this part of the vm system is known to have
+      deficiencies
+    <braunr> which is why all mach based implementations have rewritten their
+      default pager
+    <mcsim> what kind of deficiencies?
+    <braunr> bugs
+    <braunr> and design issues, making anonymous memory fragmentation horrible
+    <antrik> mcsim: vm_allocate doesn't return a memory object; so it can't be
+      passed to clients for mmap()
+    <mcsim> antrik: I use vm_allocate in pager_read_page
+    <antrik> mcsim: well, that means that you have to actually implement a
+      pager yourself
+    <antrik> also, when the kernel asks the pager to write back some pages, it
+      expects the memory to become free. if you are "paging" to ordinary
+      anonymous memory, this doesn't happen; so I expect it to have a very bad
+      effect on system performance
+    <antrik> both can be avoided by just passing a real anonymous memory
+      object, i.e. one provided by the defpager
+    <antrik> only problem is that the current defpager implementation can't
+      really handle that...
+    <antrik> at least that's my understanding of the situation
diff --git a/hurd/virtual_file_system/discussion.mdwn b/hurd/virtual_file_system/discussion.mdwn
new file mode 100644
index 00000000..9e12d01e
--- /dev/null
+++ b/hurd/virtual_file_system/discussion.mdwn
@@ -0,0 +1,39 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_documentation]]
+
+IRC, freenode, #hurd, 2011-11-12:
+
+    <sea4ever> So hurd implements a 'transparent translator' somewhere which
+      just passes all IO calls to the posix IO I'm used to? (i.e. read, write,
+      open, close, etc.?)
+    <youpi> it's the normal way of operation
+    <youpi> glibc's read() doesn't do a system call, it always does an RPC to
+      the underlying translator
+    <youpi> be it ext2fs for /, or your foobarfs for your node
+    <sea4ever> Ok that makes sense. How does one program know which translator
+      it should refer to though?
+    <sea4ever> the read() call magically knows which process to invoke?
+    <youpi> the / translator is always known
+    <youpi> and then you ask /'s translator about /home, then /home/you, then
+      /home/you/foobar
+    <youpi> it tells you which other translator tyou have to contact
+    <youpi> that's on open
+    <sea4ever> It's a tree! Ok.
+    <youpi> the notion of fd is then simply knowing the translator
+    <sea4ever> Right. 'file descriptor' is now 'translator address descriptor'
+      maybe.
+    <youpi> it's glibc which knows about FDs, nothing else knows
+    <youpi> yes
+    <youpi> actually an RPC port, simply
+    <sea4ever> I want to try out the new RPC mechanism that mach implements
+    <youpi> err, which "new" RPC ?
+    <youpi> mach's RPCs are very old actually :)