On Tue, May 18, 2021 at 6:12 PM Mike Rapoport <rppt@xxxxxxxxxx> wrote:
>
> On Mon, May 17, 2021 at 07:20:42PM +0800, Dong Aisheng wrote:
> > The only path to call memory_present() is from memblocks_present().
> > The struct mem_section **mem_section only needs to be initialized once,
> > so no need put the initialization/allocation code in memory_present()
> > which will be called multiple times for each section.
> >
> > After moving, the 'unlikely' condition statement becomes to be
> > meaningless as it's only initialized one time, so dropped as well.
> >
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> > ---
> > mm/sparse.c | 23 ++++++++++-------------
> > 1 file changed, 10 insertions(+), 13 deletions(-)
> >
> > diff --git a/mm/sparse.c b/mm/sparse.c
> > index 98bfacc763da..df4418c12f04 100644
> > --- a/mm/sparse.c
> > +++ b/mm/sparse.c
> > @@ -254,19 +254,6 @@ static void __init memory_present(int nid, unsigned long start, unsigned long en
> > {
> > unsigned long pfn;
> >
> > -#ifdef CONFIG_SPARSEMEM_EXTREME
> > - if (unlikely(!mem_section)) {
> > - unsigned long size, align;
> > -
> > - size = sizeof(struct mem_section *) * NR_SECTION_ROOTS;
> > - align = 1 << (INTERNODE_CACHE_SHIFT);
> > - mem_section = memblock_alloc(size, align);
> > - if (!mem_section)
> > - panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
> > - __func__, size, align);
> > - }
> > -#endif
>
> Maybe split this into a helper function and call it directly from
> sparse_init()?
>
Sounds good to me
e.g. sparse_alloc_section_root() called directly from sparse_init().
Thanks for the suggestion
Regards
Aisheng
> > -
> > start &= PAGE_SECTION_MASK;
> > mminit_validate_memmodel_limits(&start, &end);
> > for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
> > @@ -292,9 +279,19 @@ static void __init memory_present(int nid, unsigned long start, unsigned long en
> > */
> > static void __init memblocks_present(void)
> > {
> > + unsigned long __maybe_unused size, align;
> > unsigned long start, end;
> > int i, nid;
> >
> > +#ifdef CONFIG_SPARSEMEM_EXTREME
> > + size = sizeof(struct mem_section *) * NR_SECTION_ROOTS;
> > + align = 1 << (INTERNODE_CACHE_SHIFT);
> > + mem_section = memblock_alloc(size, align);
> > + if (!mem_section)
> > + panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
> > + __func__, size, align);
> > +#endif
> > +
> > for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid)
> > memory_present(nid, start, end);
> > }
> > --
> > 2.25.1
> >
> >
>
> --
> Sincerely yours,
> Mike.
