Hi Mike, On Sun, Oct 25, 2020 at 11:42:53PM +0800, Mike Rapoport wrote: > On Fri, Oct 16, 2020 at 05:14:00PM +0800, Zhenhua Huang wrote: > > Page owner of pages used by page owner itself used is missing on arm32 > targets. > > The reason is dummy_handle and failure_handle is not initialized > correctly. > > Buddy allocator is used to initialize these two handles. However, buddy > > allocator is not ready when page owner calls it. This change fixed that > by > > initializing page owner after buddy initialization. > > > > The working flow before and after this change are: > > original logic: > > 1. allocated memory for page_ext(using memblock). > > Is anything that requires a memblock allocation FLATMEM? > Any fundamental reason why wouldn't alloc_pages_exact_nid/vzalloc_node() > work in this case? > > It seems to me that for FLATMEM configuration we can allocate the > page_ext using alloc_pages() with a fallback to vzalloc_node() and then > we can unify lot's of page_ext code and entirely drop > page_ext_init_flatmem(). > >From comments in codes: "page_ext requires contiguous pages, bigger than MAX_ORDER unless SPARSEMEM." The size of page_ext for FLATMEM(which used pgdat) should be much larger than the size for SPARSEMEM which used section.
> > 2. invoke the init callback of page_ext_ops like > > page_owner(using buddy allocator). > > 3. initialize buddy. > > > > after this change: > > 1. allocated memory for page_ext(using memblock). > > 2. initialize buddy. > > 3. invoke the init callback of page_ext_ops like > > page_owner(using buddy allocator). > > > > with the change, failure/dummy_handle can get its correct value and > > page owner output for example has the one for page owner itself: > > Page allocated via order 2, mask 0x6202c0(GFP_USER|__GFP_NOWARN), pid > 1006, ts > > 67278156558 ns > > PFN 543776 type Unmovable Block 531 type Unmovable Flags 0x0() > > init_page_owner+0x28/0x2f8 > > invoke_init_callbacks_flatmem+0x24/0x34 > > start_kernel+0x33c/0x5d8 > > (null) > > > > Signed-off-by: Zhenhua Huang <[email protected]> > > --- > > include/linux/page_ext.h | 8 ++++++++ > > init/main.c | 2 ++ > > mm/page_ext.c | 8 +++++++- > > 3 files changed, 17 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h > > index cfce186..aff81ba 100644 > > --- a/include/linux/page_ext.h > > +++ b/include/linux/page_ext.h > > @@ -44,8 +44,12 @@ static inline void page_ext_init_flatmem(void) > > { > > } > > extern void page_ext_init(void); > > +static inline void page_ext_init_flatmem_late(void) > > +{ > > +} > > #else > > extern void page_ext_init_flatmem(void); > > +extern void page_ext_init_flatmem_late(void); > > static inline void page_ext_init(void) > > { > > } > > @@ -76,6 +80,10 @@ static inline void page_ext_init(void) > > { > > } > > > > +static inline void page_ext_init_flatmem_late(void) > > +{ > > +} > > + > > static inline void page_ext_init_flatmem(void) > > { > > } > > diff --git a/init/main.c b/init/main.c > > index 130376e..b34c475 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -818,6 +818,8 @@ static void __init mm_init(void) > > init_debug_pagealloc(); > > report_meminit(); > > mem_init(); > > + /* page_owner must be initialized after buddy is ready */ > > + page_ext_init_flatmem_late(); > > kmem_cache_init(); > > kmemleak_init(); > > pgtable_init(); > > diff --git a/mm/page_ext.c b/mm/page_ext.c > > index a3616f7..373f7a1 100644 > > --- a/mm/page_ext.c > > +++ b/mm/page_ext.c > > @@ -99,6 +99,13 @@ static void __init invoke_init_callbacks(void) > > } > > } > > > > +#if !defined(CONFIG_SPARSEMEM) > > +void __init page_ext_init_flatmem_late(void) > > +{ > > + invoke_init_callbacks(); > > +} > > +#endif > > + > > static inline struct page_ext *get_entry(void *base, unsigned long > index) > > { > > return base + page_ext_size * index; > > @@ -177,7 +184,6 @@ void __init page_ext_init_flatmem(void) > > goto fail; > > } > > pr_info("allocated %ld bytes of page_ext\n", total_usage); > > - invoke_init_callbacks(); > > return; > > > > fail: > > -- > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora > Forum, > > a Linux Foundation Collaborative Project > > > > > > -- > Sincerely yours, > Mike. >
