"That sounds like a flush to me. Modified data is written back (or flushed) to main memory." That's one possible meaning of "flush"; however it's common to use

"That sounds like a flush to me. Modified data is written back (or flushed) to main memory." That's one possible meaning of "flush"; however it's common to use it to mean not just "push dirty stuff out" but also "all your data is stale so drop it on the floor and refetch from the level below if anybody asks for it later". On x86 the "CLFLUSH" instruction does both "write modified data out to the level below" and "forget about the possibly stale cached copy you have". ARM generally avoids the term "flush" altogether and talks about "Invalidate" and "Clean" operations (where "Clean and Invalidate" does roughly the same as the x86 "CLFLUSH"). I guess this sounds a bit like nitpicking, except that in my experience if you're down at the level where you need to really care about what the cache is doing you probably also need to be precise in discussion of exactly what (possibly architecture specific) operations you're doing to your cache.