August 2013 - kernelnewbies@kernelnewbies.org

removing an Installed Kernel
by Arun M Kumar Aug. 30, 2013

Aug. 30, 2013

I have compiled and installed a kernel, Now it fails to Load...and i want to remove it.... what is the procedure to be followed, I have installed GRUB 1 on my system fr simplicity during this process.

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How to configure bullseye code coverage on windows driver
by Nitin Kshirsagar Aug. 30, 2013

Aug. 30, 2013

Hello All, I am configuring bullseye code coverage for windows MSI build. I am able to get user code coverage but not driver code coverage. Please let me know if any one configured bullseye on windows. -- Thanks & Regards, Nitin Kshirsagar

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Failed to load modules.dep
by Arun M Kumar Aug. 30, 2013

Aug. 30, 2013

I have compiled a Kernel 3.9.10 with "allyesconfig", now it fails to boot and gives some error of this kind during boot *FATAL: failed to load <xxx>/linux.3.9.10/modules.dep* I am NOT writing the exact error as it passes away too swiftly during the boot process for me to notice, but it was something on similar lines. its a long error, but something like this shows up, it again tries to load modules three to four times and comes back and halts at the same error. what could have gone wrong during the build process?

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Re: Given a page, How to get the NUMA node id of this page
by Valdis.Kletnieks＠vt.edu Aug. 29, 2013

Aug. 29, 2013

On Fri, 30 Aug 2013 04:39:14 +0800, ajay saini said: > I am working on BLCR (a checkpoint/Restart Linux kernel module), currently it > does not have this information. Yes, but why are you re-inventing the wheel? Is there a reason the existing in-kernel support for C/R isn't usable for your situation?

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Given a page, How to get the NUMA node id of this page
by ajay saini Aug. 29, 2013

Aug. 29, 2013

Hi all, I am working on a checkpoint/Restart Linux kernel module. Wherein, a process sends a request to this module to checkpoint itself. In this process information about the process is stored in a file, which is used later on to restart the process. Now when this module is storing the information related to pages (of the process) in a file, we also want to know on which NUMA node this page was assigned Can you suggest what will be the best way to get this data (page to NUMA node mapping) I tried using page_to_nid(page), but I am not really sure it gives me correct value. (Like, I am working on linux 2.6.32, 64 bit machine with 16 cores and there are 4 NUMA nodes (4 cores on each) on it, but this function returns 32 when called) Thanks, Ajay

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How to understand the codes about dentry ?
by lx Aug. 29, 2013

Aug. 29, 2013

hi all the codes about filesystem in the kernel is: static inline struct list_head * d_hash(struct dentry *parent, unsigned long hash){ hash += (unsigned long)parent / L1_CACHE_BYTES; hash = hash^(hash>>D_HASHBITS)^(hash>>D_HASHBITS*2); return dentry_hashtable + (hash & D_HASHMASK);} I know the function parameter of hash belongs to the qstr string is looking up, and the local variableshash should add the *address of the dentry of parent*. Why count the hash value use "L1_CACHE_BYTES" , "D_HASHBITS" and "D_HASHMASK"? And How to understand the codes following ? hash += (unsigned long)parent / L1_CACHE_BYTES; hash = hash^(hash>>D_HASHBITS)^(hash>>D_HASHBITS*2);

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Magic number in kernel version string
by Woody Wu Aug. 29, 2013

Aug. 29, 2013

Hi, In my own built kernel, its version string (via uname -a) has a magic number: 'Linux MyProd 3.x.x-LOCALVERSION-9b5c9ab2-dirty' I want to understand, where the '9b5c9ab2-dirty' comes from and how can I change it? Thanks. -- I can't go back to yesterday - because I was a different person then

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[PATCH 1/1] Squashfs: Optimized uncompressed buffer loop
by Manish Sharma Aug. 29, 2013

Aug. 29, 2013

Merged the two for loops. We might get a little gain by overlapping wait_on_bh and the memcpy operations. Signed-off-by: Manish Sharma <manishrma(a)gmail.com> --- fs/squashfs/block.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c index fb50652..5012f98 100644 --- a/fs/squashfs/block.c +++ b/fs/squashfs/block.c @@ -169,12 +169,6 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index, */ int i, in, pg_offset = 0; - for (i = 0; i < b; i++) { - wait_on_buffer(bh[i]); - if (!buffer_uptodate(bh[i])) - goto block_release; - } - for (bytes = length; k < b; k++) { in = min(bytes, msblk->devblksize - offset); bytes -= in; @@ -185,6 +179,9 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index, } avail = min_t(int, in, PAGE_CACHE_SIZE - pg_offset); + wait_on_buffer(bh[k]); + if (!buffer_uptodate(bh[k])) + goto block_release; memcpy(buffer[page] + pg_offset, bh[k]->b_data + offset, avail); in -= avail; -- 1.7.9.5

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Why boot logo needs framebuffer console enabled?
by Woody Wu Aug. 28, 2013

Aug. 28, 2013

Hi, In order to have a logo (full screen on my LCD) displayed when kernel booting, I have to enable framebuffer console. But, to me, the LCD is not a console, my console is just on a serial terimal. Can I have the boot logo shown without enabling the framebuffer console? Thanks in advance -- I can't go back to yesterday - because I was a different person then

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How out input/output devices of a virtual terminal
by Woody Wu Aug. 28, 2013

Aug. 28, 2013

Hi, List I have a framebuffer console which is mapped to /dev/tty1 after kernel startup. I know the output device is /dev/fb0 for this console, but don't know what is its input device. How can I find out it? In my system, following things are possible: serial line, touch screen, mice ... Thanks in advance. -- I can't go back to yesterday - because I was a different person then

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