On Thu, 4 Apr 2013, Mikulas Patocka wrote: > There are no scalability problems regarding performance - device mapper > uses btree to search the target table, so the number of target don't > affect performance. > > device mapper uses vmalloc to alloc all targets linearly, so it is limited > by avaiable vmalloc space. It is not a problem on x86-64, but it is > limited on x86 - vmalloc space can be as low as 128k (one target structure > has 64 bytes for 32-bit architectures and 96 bytes for 64-bit > architectures). BTW. when I see that btree code in dm-table.c, I ask - why doesn't it use binary search? We only append targets at the end when constructing the device, we never insert or remove them, so we don't need a tree. For these operations binary search would be as good as btree and it is simpler. Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
