Hi Onkar.... On Wed, Apr 7, 2010 at 17:56, Onkar Mahajan <kern.devel@xxxxxxxxx> wrote: > static struct hlist_head *inode_hashtable __read_mostly; > > > what is the use of __read_mostly ? > > I did not find any detailed documentation for this > on GCC website , Is it GCC optimization feature ? I failed to search the definition in kernel source or gcc docs. However, I am pretty confidence that this is somekind of definition to mark the related variable/structure/whatever and put them into the same memory segment. By doing so, the programmers are hoping that these data are grouped into the same cache line. And since they are mostly read only, cache won't be invalidated too much (maybe zero in some cases) if there is update into that cache line. Does this clear your doubt? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
