在 2023/3/17 20:06, Vlastimil Babka 写道: > On 3/17/23 12:32, chenjun (AM) wrote: >> 在 2023/3/14 22:41, Vlastimil Babka 写道: >>>> pc.flags = gfpflags; >>>> + >>>> + /* >>>> + * when (node != NUMA_NO_NODE) && (gfpflags & __GFP_THISNODE) >>>> + * 1) try to get a partial slab from target node with __GFP_THISNODE. >>>> + * 2) if 1) failed, try to allocate a new slab from target node with >>>> + * __GFP_THISNODE. >>>> + * 3) if 2) failed, retry 1) and 2) without __GFP_THISNODE constraint. >>>> + */ >>>> + if (node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE) && try_thisnode) >>>> + pc.flags |= __GFP_THISNODE; >>> >>> Hmm I'm thinking we should also perhaps remove direct reclaim possibilities >>> from the attempt 2). In your qemu test it should make no difference, as it >>> fills everything with kernel memory that is not reclaimable. But in practice >>> the target node might be filled with user memory, and I think it's better to >>> quickly allocate on a different node than spend time in direct reclaim. So >>> the following should work I think? >>> >>> pc.flags = GFP_NOWAIT | __GFP_NOWARN |__GFP_THISNODE >>> >> >> Hmm, Should it be that: >> >> pc.flags |= GFP_NOWAIT | __GFP_NOWARN |__GFP_THISNODE > > No, we need to ignore the other reclaim-related flags that the caller > passed, or it wouldn't work as intended. > The danger is that we ignore some flag that would be necessary to pass, but > I don't think there's any? > > If we ignore __GFP_ZERO passed by kzalloc， kzalloc will not work. Could we just unmask __GFP_RECLAIMABLE | __GFP_RECLAIM? pc.flags &= ~(__GFP_RECLAIMABLE | __GFP_RECLAIM) pc.flags |= __GFP_THISNODE
