Joonsoo Kim [off-list ref] writes:

On Tue, Aug 30, 2016 at 04:09:37PM +0530, Aneesh Kumar K.V wrote:

quoted

Joonsoo Kim [off-list ref] writes:

quoted

2016-08-29 18:27 GMT+09:00 Aneesh Kumar K.V [off-list ref]:

quoted

js1304@gmail.com writes:

quoted

From: Joonsoo Kim <redacted>

Hello,

Changes from v4
o Rebase on next-20160825
o Add general fix patch for lowmem reserve
o Fix lowmem reserve ratio
o Fix zone span optimizaion per Vlastimil
o Fix pageset initialization
o Change invocation timing on cma_init_reserved_areas()

I don't see much information regarding how we interleave between
ZONE_CMA and other zones for movable allocation. Is that explained in
any of the patch ? The fair zone allocator got removed by
e6cbd7f2efb433d717af72aa8510a9db6f7a7e05

Interleaving would not work since the fair zone allocator policy is removed.
I don't think that it's a big problem because it is just matter of
timing to fill
up the memory. Eventually, memory on ZONE_CMA will be fully used in
any case.

Does that mean a CMA allocation will now be slower because in most case we
will need to reclaim ? The zone list will now have ZONE_CMA in the
beginning right ?

ZONE_CMA will be used first but I don't think that CMA allocation will
be slower. In most case, memory would be fully used (usually
by page cache). So, we need reclaim or migration in any case.

Considering that the upstream kernel doesn't allow migration of THP
pages, this would mean that migrate will fail in most case if we have
THP enabled and the THP allocation request got satisfied via ZONE_CMA.
Isn't that going to be a problem ?

-aneesh

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>