On Tue, 2012-10-16 at 15:27 -0300, Ezequiel Garcia wrote: > Yes, we have some numbers: > > http://elinux.org/Kernel_dynamic_memory_analysis#Kmalloc_objects > > Are they too informal? I can add some details... > > They've been measured on a **very** minimal setup, almost every option > is stripped out, except from initramfs, sysfs, and trace. > > On this scenario, strings allocated for file names and directories > created by sysfs > are quite noticeable, being 4-16 bytes, and produce a lot of fragmentation from > that 32 byte cache at SLAB. > > Is an option to enable small caches on SLUB and SLAB worth it? Random small web server : # free total used free shared buffers cached Mem: 7884536 5412572 2471964 0 155440 1803340 -/+ buffers/cache: 3453792 4430744 Swap: 2438140 51164 2386976 # grep Slab /proc/meminfo Slab: 351592 kB # egrep "kmalloc-32|kmalloc-16|kmalloc-8" /proc/slabinfo kmalloc-32 11332 12544 32 128 1 : tunables 0 0 0 : slabdata 98 98 0 kmalloc-16 5888 5888 16 256 1 : tunables 0 0 0 : slabdata 23 23 0 kmalloc-8 76563 82432 8 512 1 : tunables 0 0 0 : slabdata 161 161 0 Really, some waste on these small objects is pure noise on SMP hosts. (Waste on bigger objects is probably more important by orders of magnitude) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>