On Tue, Apr 21, 2020 at 07:55:03PM +0800, 赵军奎 wrote: > Sure, i just received some kbuild compiler error mails and prompt me to do something? > I don`t know why this happened, so i update the patch again. Don't. The patch has been NACKed, so there's no need to post a v2. If you want to do something useful, how about looking at the effect of adding different slab sizes? There's a fairly common pattern of allocating things which are a power of two + a header. So it may make sense to have kmalloc caches of 320 (256 + 64), 576 (512 + 64) and 1088 (1024 + 64). I use 64 here as that's the size of a cacheline, so we won't get false sharing between users. This could save a fair quantity of memory; today if you allocate 512 + 8 bytes, it will round up to 1024. So we'll get 4 allocations per 4kB page, but with a 576-byte slab, we'd get 7 allocations per 4kB page. Of course, if there aren't a lot of users which allocate memory in this range, then it'll be a waste of memory. On my laptop, it seems like there might be a decent amount of allocations in the right range: kmalloc-2k 3881 4384 2048 16 8 : tunables 0 0 0 : sla bdata 274 274 0 kmalloc-1k 6488 7056 1024 16 4 : tunables 0 0 0 : slabdata 441 441 0 kmalloc-512 7700 8256 512 16 2 : tunables 0 0 0 : slabdata 516 516 0 Now, maybe 576 isn't quite the right size. Need to try it on a variety of configurations and find out. Want to investigate this?
