1. vfs_lock_file – file byte range lock 2. Manual int vfs_lock_file(struct file * filp, unsigned int cmd, struct file_lock * fl, struct file_lock * conf); filp The file to apply the lock to cmd type of locking operation (F_SETLK, F_GETLK, etc.) fl The lock to be applied conf Place to return a copy of the …
Monthly Archives: December 2011
[PATCH] udf: Fix deadlock when converting file from in-ICB one to normal one
[PATCH] udf: Fix deadlock when converting file from in-ICB one to normal one During BKL removal, conversion of files from in-ICB format to normal format got broken. We call ->writepage with i_data_sem held but udf_get_block() also acquires i_data_sem thus creating A-A deadlock. We fix the problem by dropping i_data_sem before calling ->writepage() which is safe …
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mutex_init .
1. mutex_init Initialize the mutex to unlocked state. 2. Classroom The point of a mutex is to synchronize two threads. When you have two threads attempting to access a single resource, the general pattern is to have the first block of code attempting access to set the mutex before entering the code. When the second …
tcp_rmem – vector of 3 INTEGERs: min, default, max
ABOUT tcp_rmem min: Minimal size of receive buffer used by TCP sockets. It is guaranteed to each TCP socket, even under moderate memory pressure. Default: 1 page default: initial size of receive buffer used by TCP sockets. This value overrides net.core.rmem_ default used by other protocols. Default: 87380 bytes. This value results in window of …
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BusyBox – The Swiss Army Knife of Embedded Linux
UNIX Command $dpkg -L busybox /. /bin /bin/busybox /usr /usr/share /usr/share/man /usr/share/man/man1 /usr/share/man/man1/busybox.1.gz /usr/share/doc /usr/share/doc/busybox /usr/share/doc/busybox/copyright /usr/share/doc/busybox/changelog.Debian.gz $mount /dev/sda1 on / type ext3 (rw,errors=remount-ro,commit=0) tmpfs on /lib/init/rw type tmpfs (rw,nosuid,size=5242880,mode=755,size=5242880,mode=755) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=755,size=10%,mode=755) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) udev on /dev type tmpfs (rw,mode=0755) tmpfs …
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Knowledge Drop on Virtual Terminals
virtual Terminals helps in experience of Multiple terminals on a single computer.
fs: Make write(2) interruptible by a fatal signal
Kernel Space linux-fsdevel@vger.kernel.org : Currently write(2) to a file is not interruptible by any signal. Sometimes this is desirable, e.g. when you want to quickly kill a process hogging your disk. Also, with commit 499d05ecf990 (“mm: Make task in balance_dirty_pages() killable”), it’s necessary to abort the current write accordingly to avoid it quickly dirtying lots …
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PXE Boot
Topic PXE Boot Explanation The Preboot eXecution Environment (PXE, also known as Pre-Execution Environment; sometimes pronounced “pixie”) is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems. PXE was introduced as part of the Wired for Management framework by Intel and is described …
bubble sort testing… 0.00006 Ver — 4000 No.’s related
$time php bubble.php real 0m7.404s user 0m7.012s sys 0m0.080s $time php bubble.php real 0m7.333s user 0m7.044s sys 0m0.068s $time php bubble.php real 0m7.393s user 0m7.068s sys 0m0.100s $time php bubble.php real 0m7.345s user 0m7.024s sys 0m0.104s $time php bubble.php real 0m7.545s user 0m7.224s sys 0m0.080s $time php bubble.php real 0m7.275s user 0m6.992s sys 0m0.072s $time …
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What is a TASK_KILLABLE state in Linux ?
ABOUT TASK_KILLABLE state TASK_KILLABLE sleeping state. Like most versions of Unix, Linux has two fundamental ways in which a process can be put to sleep. A process which is placed in the TASK_INTERRUPTIBLE state will sleep until either (1) something explicitly wakes it up, or (2) a non-masked signal is received. The TASK_UNINTERRUPTIBLE state, instead, …