> mm, vmscan: Only allocate and reclaim from zones with pages managed by the buddy allocator
>
> Firmware Assisted Dump (FA_DUMP) on ppc64 reserves substantial amounts
> of memory when booting a secondary kernel. Srikar Dronamraju reported that
> multiple nodes may have no memory managed by the buddy allocator but still
> return true for populated_zone().
>
> Commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes")
> was reported to cause kswapd to spin at 100% CPU usage when fadump was
> enabled. The old code happened to deal with the situation of a populated
> node with zero free pages by co-incidence but the current code tries to
> reclaim populated zones without realising that is impossible.
>
> We cannot just convert populated_zone() as many existing users really
> need to check for present_pages. This patch introduces a managed_zone()
> helper and uses it in the few cases where it is critical that the check
> is made for managed pages -- zonelist constuction and page reclaim.
one nit
s/constuction/construction/
>
Verified that it works fine.
--
Thanks and Regards
Srikar Dronamraju
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>