On Fri, Jul 19, 2024 at 07:16:47PM +0100, Jonathan Cameron wrote:
> On Tue, 16 Jul 2024 14:13:41 +0300
> Mike Rapoport <r...@kernel.org> wrote:
>
> > From: "Mike Rapoport (Microsoft)" <r...@kernel.org>
> >
> > Move code dealing with numa_memblks from arch/x86 to mm/ and add Kconfig
> > options to let x86 select it in its Kconfig.
> >
> > This code will be later reused by arch_numa.
> >
> > No functional changes.
> >
> > Signed-off-by: Mike Rapoport (Microsoft) <r...@kernel.org>
> Hi Mike,
>
> My only real concern in here is there are a few places where
> the lifted code makes changes to memblocks that are x86 only today.
> I need to do some more digging to work out if those are safe
> in all cases.
>
> Jonathan
>
>
>
> > +/**
> > + * numa_cleanup_meminfo - Cleanup a numa_meminfo
> > + * @mi: numa_meminfo to clean up
> > + *
> > + * Sanitize @mi by merging and removing unnecessary memblks. Also check
> > for
> > + * conflicts and clear unused memblks.
> > + *
> > + * RETURNS:
> > + * 0 on success, -errno on failure.
> > + */
> > +int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
> > +{
> > + const u64 low = 0;
>
> Given always zero, why not just use that value inline?
Actually it seems to me that it should be memblock_start_of_DRAM().
The blocks outside system memory are moved to numa_reserved_meminfo, so
AFAIU on arm64/riscv such blocks can be below the RAM.
> > + const u64 high = PFN_PHYS(max_pfn);
> > + int i, j, k;
> > +
> > + /* first, trim all entries */
> > + for (i = 0; i < mi->nr_blks; i++) {
> > + struct numa_memblk *bi = &mi->blk[i];
> > +
> > + /* move / save reserved memory ranges */
> > + if (!memblock_overlaps_region(&memblock.memory,
> > + bi->start, bi->end - bi->start)) {
> > + numa_move_tail_memblk(&numa_reserved_meminfo, i--, mi);
> > + continue;
> > + }
> > +
> > + /* make sure all non-reserved blocks are inside the limits */
> > + bi->start = max(bi->start, low);
> > +
> > + /* preserve info for non-RAM areas above 'max_pfn': */
> > + if (bi->end > high) {
> > + numa_add_memblk_to(bi->nid, high, bi->end,
> > + &numa_reserved_meminfo);
> > + bi->end = high;
> > + }
> > +
> > + /* and there's no empty block */
> > + if (bi->start >= bi->end)
> > + numa_remove_memblk_from(i--, mi);
> > + }
> > +
> > + /* merge neighboring / overlapping entries */
> > + for (i = 0; i < mi->nr_blks; i++) {
> > + struct numa_memblk *bi = &mi->blk[i];
> > +
> > + for (j = i + 1; j < mi->nr_blks; j++) {
> > + struct numa_memblk *bj = &mi->blk[j];
> > + u64 start, end;
> > +
> > + /*
> > + * See whether there are overlapping blocks. Whine
> > + * about but allow overlaps of the same nid. They
> > + * will be merged below.
> > + */
> > + if (bi->end > bj->start && bi->start < bj->end) {
> > + if (bi->nid != bj->nid) {
> > + pr_err("node %d [mem %#010Lx-%#010Lx]
> > overlaps with node %d [mem %#010Lx-%#010Lx]\n",
> > + bi->nid, bi->start, bi->end - 1,
> > + bj->nid, bj->start, bj->end - 1);
> > + return -EINVAL;
> > + }
> > + pr_warn("Warning: node %d [mem %#010Lx-%#010Lx]
> > overlaps with itself [mem %#010Lx-%#010Lx]\n",
> > + bi->nid, bi->start, bi->end - 1,
> > + bj->start, bj->end - 1);
> > + }
> > +
> > + /*
> > + * Join together blocks on the same node, holes
> > + * between which don't overlap with memory on other
> > + * nodes.
> > + */
> > + if (bi->nid != bj->nid)
> > + continue;
> > + start = min(bi->start, bj->start);
> > + end = max(bi->end, bj->end);
> > + for (k = 0; k < mi->nr_blks; k++) {
> > + struct numa_memblk *bk = &mi->blk[k];
> > +
> > + if (bi->nid == bk->nid)
> > + continue;
> > + if (start < bk->end && end > bk->start)
> > + break;
> > + }
> > + if (k < mi->nr_blks)
> > + continue;
> > + pr_info("NUMA: Node %d [mem %#010Lx-%#010Lx] + [mem
> > %#010Lx-%#010Lx] -> [mem %#010Lx-%#010Lx]\n",
> > + bi->nid, bi->start, bi->end - 1, bj->start,
> > + bj->end - 1, start, end - 1);
> > + bi->start = start;
> > + bi->end = end;
> > + numa_remove_memblk_from(j--, mi);
> > + }
> > + }
> > +
> > + /* clear unused ones */
> > + for (i = mi->nr_blks; i < ARRAY_SIZE(mi->blk); i++) {
> > + mi->blk[i].start = mi->blk[i].end = 0;
> > + mi->blk[i].nid = NUMA_NO_NODE;
> > + }
> > +
> > + return 0;
> > +}
>
> ...
>
>
> > +/*
> > + * Mark all currently memblock-reserved physical memory (which covers the
> > + * kernel's own memory ranges) as hot-unswappable.
> > + */
> > +static void __init numa_clear_kernel_node_hotplug(void)
>
> This will be a change for non x86 architectures. 'should' be fine
> but I'm not 100% sure.
This function sets nid to memblock.reserved which does not change anything
except the dump in debugfs and then uses the node info in memblock.reserve
to clear MEMBLOCK_HOTPLUG from the regions in memblock.memory that contain
the reserved memory because they cannot be hot(un)plugged anyway.
> > +{
> > + nodemask_t reserved_nodemask = NODE_MASK_NONE;
> > + struct memblock_region *mb_region;
> > + int i;
> > +
> > + /*
> > + * We have to do some preprocessing of memblock regions, to
> > + * make them suitable for reservation.
> > + *
> > + * At this time, all memory regions reserved by memblock are
> > + * used by the kernel, but those regions are not split up
> > + * along node boundaries yet, and don't necessarily have their
> > + * node ID set yet either.
> > + *
> > + * So iterate over all memory known to the x86 architecture,
>
> Comment needs an update at least given not x86 specific any more.
Sure, will fix.
> > + * and use those ranges to set the nid in memblock.reserved.
> > + * This will split up the memblock regions along node
> > + * boundaries and will set the node IDs as well.
> > + */
> > + for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > + struct numa_memblk *mb = numa_meminfo.blk + i;
> > + int ret;
> > +
> > + ret = memblock_set_node(mb->start, mb->end - mb->start,
> > + &memblock.reserved, mb->nid);
> > + WARN_ON_ONCE(ret);
> > + }
> > +
> > + /*
> > + * Now go over all reserved memblock regions, to construct a
> > + * node mask of all kernel reserved memory areas.
> > + *
> > + * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> > + * numa_meminfo might not include all memblock.reserved
> > + * memory ranges, because quirks such as trim_snb_memory()
> > + * reserve specific pages for Sandy Bridge graphics. ]
> > + */
> > + for_each_reserved_mem_region(mb_region) {
> > + int nid = memblock_get_region_node(mb_region);
> > +
> > + if (nid != MAX_NUMNODES)
> > + node_set(nid, reserved_nodemask);
> > + }
> > +
> > + /*
> > + * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
> > + * belonging to the reserved node mask.
> > + *
> > + * Note that this will include memory regions that reside
> > + * on nodes that contain kernel memory - entire nodes
> > + * become hot-unpluggable:
> > + */
> > + for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > + struct numa_memblk *mb = numa_meminfo.blk + i;
> > +
> > + if (!node_isset(mb->nid, reserved_nodemask))
> > + continue;
> > +
> > + memblock_clear_hotplug(mb->start, mb->end - mb->start);
> > + }
> > +}
>
--
Sincerely yours,
Mike.
