Hi.... Probably just a quick share from me... On Fri, Mar 18, 2011 at 06:18, Maksym Planeta <mcsim.planeta@gmail.com> wrote:
I've wrote a hook were I've counted witch object sizes are the most popular.
Uhuh, and why you just don't use "slabtop" utility which just use /proc/slabinfo?
They were objects of sizes 8 and 16 bytes, but the smallest available cache has size 32 bytes. So in this cache fragmentation is about 40%. There is big fragmentation in 512 and 1024-byte caches too -- 25 and 35 percent correspondingly. Also there are empty caches, all DMA caches on my system are empty. In total there is wasting of memory.
I think 32 byte is chosen due to the size of the page in x86 32 bit == 4 KiB... by doing that, cache is simply allocated using page_alloc (or alloc_page? I forgot) and then later "teared apart" into slab objects... -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com