On 9/8/20 5:31 PM, Marco Elver wrote: >> >> How much memory overhead does this end up having? I know it depends on >> the object size and so forth. But, could you give some real-world >> examples of memory consumption? Also, what's the worst case? Say I >> have a ton of worst-case-sized (32b) slab objects. Will I notice? > > KFENCE objects are limited (default 255). If we exhaust KFENCE's memory > pool, no more KFENCE allocations will occur. > Documentation/dev-tools/kfence.rst gives a formula to calculate the > KFENCE pool size: > > The total memory dedicated to the KFENCE memory pool can be computed as:: > > ( #objects + 1 ) * 2 * PAGE_SIZE > > Using the default config, and assuming a page size of 4 KiB, results in > dedicating 2 MiB to the KFENCE memory pool. > > Does that clarify this point? Or anything else that could help clarify > this? Hmm did you observe that with this limit, a long-running system would eventually converge to KFENCE memory pool being filled with long-aged objects, so there would be no space to sample new ones? > Thanks, > -- Marco >
