Messages in this thread | | | Date | Mon, 26 Oct 2020 20:42:26 +0800 | From | Zhenhua Huang <> | Subject | Re: [PATCH] mm: fix page_owner initializing issue for arm32 |
| |
On Mon, Oct 26, 2020 at 05:39:34PM +0800, Mike Rapoport wrote: > On Mon, Oct 26, 2020 at 03:12:55PM +0800, Zhenhua Huang wrote: > > 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. > > Well, the vzalloc_node() fallback in alloc_page_ext() for SPARSEMEM case > implies that using pages that are not physically contiguous should be > fine. So, it seems to me that the comment is stale and vzalloc_node() > would work just fine for FLATMEM case if the allocation of page_ext > would exceed MAX_ORDER. >
Thanks Mike, got it. I agree with you for this point. I also haven't got why it needs physical continuous... and haven't found detailed commit message explained it.
> > > > 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 <zhenhuah@codeaurora.org> > > > > --- > > > > 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. > > > > > -- > Sincerely yours, > Mike. >
| |