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eudyptula challenge, stuck at task 06 - no reply for four weeks
by Alexander Ivanov Dec. 31, 2015

Dec. 31, 2015

Hi there, Is there anybody stuck at task 06 too? --ami

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回复：Re: some question about arch/x86/kernel/head_64.S
by hitmoon Dec. 30, 2015

Dec. 30, 2015

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some question about arch/x86/kernel/head_64.S
by xiaoqiang zhao Dec. 30, 2015

Dec. 30, 2015

Hello: After kernel is decompressed, the kernel will execute startup_64 and the first two instructions are: leaq _text(%rip), %rbp subq $_text - __START_KERNEL_map, %rbp I tried to understand them but can not figure out what rbp contains after this two instructions. Anybody give me a clear explanation? Thanks a lot!

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Developing environments used for kernel development
by Daniel. Dec. 29, 2015

Dec. 29, 2015

My boss came to my desk today raiging that I should use more productive tools for developing. Well I don't want to begin an editor war but, yes, I use emacs. I used to use vim before but the integration of emacs and gdb has caught my attention. To be clear, as "more productive tools" he understands graphical eye candy tools. My argument to use an "simple editor plus makefiles" was, it just works and thats it. So before to downloading eclipse just to make my boss's eyes happy I've decided to make a little research. What you guys are using today to develope kenrel code? Best Regards, - dhs -- *"Do or do not. There is no try"* *Yoda Master*

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Trivial patches and lots of maintainers
by Manuel Pégourié-Gonnard Dec. 28, 2015

Dec. 28, 2015

Hi, When submitting trivial patches such as fixing typos in comments, should I always Cc all people suggested by get_maintainer.pl? For example, I noticed a typo in comments in drivers/base/power/common.c for which get_maintainers.pl suggests 4 individuals plus 2 mailings lists (to which I think I should add the Trivial Patch Monkey). Intuitively, it feels wrong to personally spam 4 people for such a trivial thing. OTOH, maybe it's OK because those people are used to handle a very large volume of email anyway, and they prefer to have an opportunity to see everything, no matter how trivial. What's the best usage here? Thanks, Manuel.

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first patch
by maoma king Dec. 27, 2015

Dec. 27, 2015

Dear I have sent my first patch (https://lkml.org/lkml/2015/11/18/239) to linux-next tree.But I never received anything about it.So I sent it again. You say "Doesn't apply to my tree :(".but it can be apply to least linux-next branch . I make n new patch and send it.I receive review(https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1048115… . I want to know what's wrong with me? how do I know that my patch is accepted?

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how to reduce both vmlinuz size and modules?
by Robert P. J. Day Dec. 27, 2015

Dec. 27, 2015

currently running latest version of fedora 23, with 4.2.8-200.fc22.x86_64 fedora kernel package, and i'm wondering about the best way to both reduce the kernel size, and cut down on the number of modules i'm building, based on what looks like combining a couple of make targets. if i start with the latest git kernel repo, it *looks* like i can use the /boot/config-4.2.8-200.fc22.x86_64 config file as a starting point, copy it in as .config, then: $ make allmodconfig $ make localmodconfig as i read it (and i could be mistaken), the first make would transform as many "y" kernel selections to "m" as possible, while the second would then remove any module config selections that are currently not loaded. am i reading that correctly? is there a simpler way to do this? rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

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Fwd: Re: [PATCH] allow strictatime to be set as a global default
by Raymond Jennings Dec. 25, 2015

Dec. 25, 2015

I've been cooking a very simple patch that hopefully gives both sides of the "great strictatime war" what they want with minimal pain. I sent it through kernelnewbies for a basic review and got some polish on irc. ---- Signed-off-by: Raymond Jennings <shentino(a)gmail.com> Reviewed-by: Mandeep Sandhu <mandeepsandhu.chd(a)gmail.com> diff --git a/fs/Kconfig b/fs/Kconfig index 6ce72d8..122a993 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -4,6 +4,20 @@ menu "File systems" +config DEFAULT_STRICTATIME + bool "Use strictatime by default" + default n + help + Use strictatime as a default mount option. + + Relatime became the default in 2007 to reduce I/O load on block devices. + + Enabling this option will restore historic behavior and provide perfectly + accurate atimes, but the increase in write load may reduce performance + and shorten the life of the block device. + + If unsure, say N. + # Use unaligned word dcache accesses config DCACHE_WORD_ACCESS bool diff --git a/fs/namespace.c b/fs/namespace.c index 0570729..48e7c15 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2680,9 +2680,15 @@ long do_mount(const char *dev_name, const char __user *dir_name, if (retval) goto dput_out; - /* Default to relatime unless overriden */ +#ifdef CONFIG_DEFAULT_STRICTATIME + /* Default to strictatime unless overridden */ + if (flags & MS_RELATIME) + mnt_flags |= MNT_RELATIME; +#else + /* Default to relatime unless overridden */ if (!(flags & MS_NOATIME)) mnt_flags |= MNT_RELATIME; +#endif /* Separate the per-mountpoint flags */ if (flags & MS_NOSUID) ---------- Forwarded message ---------- From: Mandeep Sandhu <mandeepsandhu.chd(a)gmail.com> Subject: Re: [PATCH] allow strictatime to be set as a global default Date: Sat, 19 Dec 2015 17:25:37 -0800 To: Raymond Jennings <shentino(a)gmail.com> Cc: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Looks good to me. To test the real waters....you should send it to the lists you mentioned (or whatever the maintainers script tells you). Good luck, -mandeep On Sat, Dec 19, 2015 at 1:41 PM, Raymond Jennings <shentino(a)gmail.com> wrote: > How does this version look? > > (the other delta for the other file was untouched) > > Any chance it is ready to post to the big list (presumably fs with a > cc to > lkml)? > > diff --git a/fs/Kconfig b/fs/Kconfig > index 6ce72d8..122a993 100644 > --- a/fs/Kconfig > +++ b/fs/Kconfig > @@ -4,6 +4,20 @@ > > menu "File systems" > > +config DEFAULT_STRICTATIME > + bool "Use strictatime by default" > + default n > + help > + Use strictatime as a default mount option. > + > + Relatime became the default in 2007 to reduce I/O load on block > devices. > + > + Enabling this option will restore historic behavior and provide > perfectly > + accurate atimes, but the increase in write load may reduce > performance > + and shorten the life of the block device. > + > + If unsure, say N. > + > # Use unaligned word dcache accesses > config DCACHE_WORD_ACCESS > bool > > On Fri, Dec 18, 2015 at 2:21 PM, Mandeep Sandhu > <mandeepsandhu.chd(a)gmail.com> wrote: >> >> Ah yes...now it makes sense! :) >> >> The current 'word of caution' (about increased I/O load on block >> devices), seems mild IMHO. Maybe we should we have a stricter >> warning...something like enabling this option might be harmful to >> the >> life of your block device (due to excessive writes) and will also >> lead >> to reduced performance? >> >> HTH, >> -mandeep >> >> >> On Fri, Dec 18, 2015 at 2:12 PM, Raymond Jennings >> <shentino(a)gmail.com> >> wrote: >> > On Fri, Dec 18, 2015 at 10:50 AM, Mandeep Sandhu >> > <mandeepsandhu.chd(a)gmail.com> wrote: >> >> >> >> You've removed the strictatime option altogether. So how does >> that >> >> satisfy people who _do_ want it? >> > >> > >> > ...actually it looks like I was an idiot and got my diff >> backwards when >> > I >> > pulled it out of git :P >> > >> > Here's the correct version. >> > >> > diff --git a/fs/Kconfig b/fs/Kconfig >> > index 6ce72d8..4b917eb 100644 >> > --- a/fs/Kconfig >> > +++ b/fs/Kconfig >> > @@ -4,6 +4,17 @@ >> > >> > menu "File systems" >> > >> > +config DEFAULT_STRICTATIME >> > + bool "Use strictatime by default" >> > + default n >> > + help >> > + Use strictatime as a default mount option. >> > + >> > + Strictatime preserves ancient historic behavior of >> keeping the >> > atime field always up to date. >> > + However, it was changed in 2007 to relatime to reduce >> I/O load >> > on >> > block devices. >> > + >> > + If unsure, say N. >> > + >> > # Use unaligned word dcache accesses >> > config DCACHE_WORD_ACCESS >> > bool >> > diff --git a/fs/namespace.c b/fs/namespace.c >> > index 0570729..48e7c15 100644 >> > --- a/fs/namespace.c >> > +++ b/fs/namespace.c >> > @@ -2680,9 +2680,15 @@ long do_mount(const char *dev_name, const >> char >> > __user >> > *dir_name, >> > if (retval) >> > goto dput_out; >> > >> > - /* Default to relatime unless overriden */ >> > +#ifdef CONFIG_DEFAULT_STRICTATIME >> > + /* Default to strictatime unless overridden */ >> > + if (flags & MS_RELATIME) >> > + mnt_flags |= MNT_RELATIME; >> > +#else >> > + /* Default to relatime unless overridden */ >> > if (!(flags & MS_NOATIME)) >> > mnt_flags |= MNT_RELATIME; >> > +#endif >> > >> > >> > /* Separate the per-mountpoint flags */ >> > if (flags & MS_NOSUID) >> > >> > >> > > >

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what is the rationale for "uio-howto.aux.xml" DocBook file?
by Robert P. J. Day Dec. 25, 2015

Dec. 25, 2015

just noticed for the first time the in-kernel Doc file uio-howto.aux.xml (sitting next to uio-howto.xml). the latter file is the one processed by "make htmldocs", so what is the purpose of that former one? i don't see where/how it's being picked up. any hints? am i missing something painfully obvious? rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

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[PATCH] allow strictatime to be set as a global default
by Raymond Jennings Dec. 20, 2015

Dec. 20, 2015

I'm aware of a little tiff regarding strictatime in the past, and I think I came up with a patch that might help everyone get what they want. I'm already using it myself. I've had some review on #kernelnewbies for technical issues, how does this look? --- diff --git a/fs/Kconfig b/fs/Kconfig index 4b917eb..6ce72d8 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -4,17 +4,6 @@ menu "File systems" -config DEFAULT_STRICTATIME - bool "Use strictatime by default" - default n - help - Use strictatime as a default mount option. - - Strictatime preserves ancient historic behavior of keeping the atime field always up to date. - However, it was changed in 2007 to relatime to reduce I/O load on block devices. - - If unsure, say N. - # Use unaligned word dcache accesses config DCACHE_WORD_ACCESS bool diff --git a/fs/namespace.c b/fs/namespace.c index 48e7c15..0570729 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2680,15 +2680,9 @@ long do_mount(const char *dev_name, const char __user *dir_name, if (retval) goto dput_out; -#ifdef CONFIG_DEFAULT_STRICTATIME - /* Default to strictatime unless overridden */ - if (flags & MS_RELATIME) - mnt_flags |= MNT_RELATIME; -#else - /* Default to relatime unless overridden */ + /* Default to relatime unless overriden */ if (!(flags & MS_NOATIME)) mnt_flags |= MNT_RELATIME; -#endif /* Separate the per-mountpoint flags */ if (flags & MS_NOSUID)

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