On 8/29/05, Thayumanavar Sachithanantham <thayumker@xxxxxxxxx> wrote: > > Hi, > > > > Just wanted to know, is it a good idea to kmalloc for a small > > structure. For example if I define a structure in kernel of 10 bytes, > > and I want to get the memory allocated dynamically for it N number of > > times, is it good to kmalloc for it every time. > > > > As kmalloc() allocates the memory in terms of page size (4k), atleast > > 4K will be allocated for each kmalloc() call in above case. On other > > side, wont it be good idea to get one page allocated with kmalloc() > > and then use it to store an array of our 10 byte structure and if we > > need more we can get one more page allocated with kmalloc(). In this > > way we can have list of kmalloc'ed pages and each page represents the > > array of out 10 byte strucutre. > > > > The kmalloc memory allocator is built on top of the slab allocator. So > to allocate a structure of 10 bytes, it will allocate from a slab > whose object size is 32 bytes. A very good description of how kmalloc > works is found at > http://infamous.hackaholic.org/Kmalloc_Internals.html. thanks for sending this link ..... seems to be a good article on kmalloc internals .... -Gaurav > On 8/29/05, Gaurav Dhiman <gaurav4lkg@xxxxxxxxx> wrote: > > Hi, > > > > Just wanted to know, is it a good idea to kmalloc for a small > > structure. For example if I define a structure in kernel of 10 bytes, > > and I want to get the memory allocated dynamically for it N number of > > times, is it good to kmalloc for it every time. > > > > As kmalloc() allocates the memory in terms of page size (4k), atleast > > 4K will be allocated for each kmalloc() call in above case. On other > > side, wont it be good idea to get one page allocated with kmalloc() > > and then use it to store an array of our 10 byte structure and if we > > need more we can get one more page allocated with kmalloc(). In this > > way we can have list of kmalloc'ed pages and each page represents the > > array of out 10 byte strucutre. > > > > I am asking this as I am adopting the second approch (list of > > kmalloc'ed pages) in one of my kernel modules, just wanted to know is > > it worth doing so much of list maintaince of kmalloc'ed pages or we > > can simply use the kmalloc for allocating memory to each structure. > > > > regards, > > -Gaurav > > > > -- > > Kernelnewbies: Help each other learn about the Linux kernel. > > Archive: http://mail.nl.linux.org/kernelnewbies/ > > FAQ: http://kernelnewbies.org/faq/ > > > > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
