Hello,
after munching many (not very helpful) materials on google and kernel
doc, I asked a kernelist about this topic.
Q: Where do I get a list of wchan functions?
A: It simply shows the name of the last function which called schedule()
or anything else marked as "__sched" in sources. You can get the
function names looking into System.map or /proc/kallsyms.
Q: Is it possible that there can be two or more wait channels of the
same name (with or without prefixes sys_ or do_ or whatever)?
A: Yes, two static functions can have the same name.
So now it makes sense that if jbd2_journal_get_write_access() (somehow
stripped to get_write_access) calls schedule(), it is showed in wchan,
same as do_get_write_access.
[localhost 4.7.10-100.fc23.x86_64]$ sudo cat System.map|grep
get_write_access
ffffffff812d5430 T do_journal_get_write_access
ffffffff8130b0a0 T __ext4_journal_get_write_access
ffffffff81325d10 t do_get_write_access
ffffffff81326140 T jbd2_journal_get_write_access
ffffffff81af0a40 R __ksymtab_jbd2_journal_get_write_access
ffffffff81b14a02 r __kstrtab_jbd2_journal_get_write_access
I find this as another reason to remove the stripping at all, cancel my
merge request and send another one removing it.
Jan
On 11/05/2016 12:24 AM, Craig Small wrote:
I'll need to know if it is a case of someone getting a kernel call and a
library call confused (which means no from me) OR it is two different
kernel calls (which means a yes).
- Craig
On Sat, Nov 5, 2016 at 10:13 AM Jim Warner <james.warner@xxxxxxxxxxx
<mailto:james.warner@xxxxxxxxxxx>> wrote:
On 11/04/2016 05:53 PM, Craig Small wrote:
> These are pretty ancient things. I suspect the reasons would be
hard to
> determine.
> ...
Hi Craig,
Not sure, but that all sounded kinda' like a vote to strip those prefix
suckers.
Right?
Regards,
Jim
--
Craig Small (@smallsees) http://dropbear.xyz/ csmall at :
enc.com.au <http://enc.com.au>
Debian GNU/Linux http://www.debian.org/ csmall at :
debian.org <http://debian.org>
GPG fingerprint: 5D2F B320 B825 D939 04D2 0519 3938 F96B DF50 FEA5
