Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> writes: > On 8/21/2023 10:29 AM, Huang, Ying wrote: >> Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> writes: >> >>> Hi, >>> >>> Currently, on our ARM servers with NUMA enabled, we found the cross-die latency >>> is a little larger that will significantly impact the workload's performance. >>> So on ARM servers we will rely on the NUMA balancing to avoid the cross-die >>> accessing. And I posted a patchset[1] to support speculative numa fault to >>> improve the NUMA balancing's performance according to the principle of data >>> locality. Moreover, thanks to Huang Ying's patchset[2], which introduced batch >>> migration as a way to reduce the cost of TLB flush, and it will also benefit >>> the migration of multiple pages all at once during NUMA balancing. >>> >>> So we plan to continue to support batch migration in do_numa_page() to improve >>> the NUMA balancing's performance, but before adding complicated batch migration >>> algorithm for NUMA balancing, some cleanup and preparation work need to do firstly, >>> which are done in this patch set. In short, this patchset extends the >>> migrate_misplaced_page() interface to support batch migration, and no functional >>> changes intended. >> Will these cleanup benefit anything except batching migration? If >> not, > > I hope these cleanup can also benefit the compound page's NUMA > balancing, which was discussed in the thread[1]. IIUC, for the > compound page's NUMA balancing, it is possible that partial pages were > successfully migrated, so it is necessary to return the number of > pages that were successfully migrated from > migrate_misplaced_page(). (But I did not look this in detail yet, > please correct me if I missed something, and I will find some time to > look this in detail). That is why I think these cleanups are > straightforward. > > Yes, I will post the batch migration patches after more polish and > testing, but I think these cleanups are separate and straightforward, > so I plan to submit the patches separately. Then, please state the benefit explicitly in the patch description instead of just preparation for batching migration. -- Best Regards, Huang, Ying > [1] > https://lore.kernel.org/all/f8d47176-03a8-99bf-a813-b5942830fd73@xxxxxxx/ > >> I suggest you to post the whole series. In this way, people will be >> more clear about why we need these cleanup. >> -- >> Best Regards, >> Huang, Ying >> >>> [1] https://lore.kernel.org/lkml/cover.1639306956.git.baolin.wang@xxxxxxxxxxxxxxxxx/t/#mc45929849b5d0e29b5fdd9d50425f8e95b8f2563 >>> [2] https://lore.kernel.org/all/20230213123444.155149-1-ying.huang@xxxxxxxxx/T/#u >>> >>> Baolin Wang (4): >>> mm: migrate: move migration validation into numa_migrate_prep() >>> mm: migrate: move the numamigrate_isolate_page() into do_numa_page() >>> mm: migrate: change migrate_misplaced_page() to support multiple pages >>> migration >>> mm: migrate: change to return the number of pages migrated >>> successfully >>> >>> include/linux/migrate.h | 15 ++++++++--- >>> mm/huge_memory.c | 19 +++++++++++--- >>> mm/memory.c | 34 +++++++++++++++++++++++- >>> mm/migrate.c | 58 ++++++++--------------------------------- >>> 4 files changed, 71 insertions(+), 55 deletions(-)
