lkml.org 
[lkml]   [2020]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] mm/page_alloc: Add a reason for reserved pages in has_unmovable_pages()
From
Date


On 01/14/2020 03:53 PM, Vlastimil Babka wrote:
> On 1/14/20 10:10 AM, Michal Hocko wrote:
>> [Cc Ralph]
>>> The reason is dump_page() does not print page->flags universally
>>> and only does so for KSM, Anon and File pages while excluding
>>> reserved pages at boot. Wondering should not we make printing
>>> page->flags universal ?
>>
>> We used to do that and this caught me as a surprise when looking again.
>> This is a result of 76a1850e4572 ("mm/debug.c: __dump_page() prints an
>> extra line") which is a cleanup patch and I suspect this result was not
>> anticipated.
>>
>> The following will do the trick but I cannot really say I like the code
>> duplication. pr_cont in this case sounds like a much cleaner solution to
>> me.
>
> How about this then?

This looks better than what we have right now though my initial thought
was similar to what Michal had suggested earlier.

>
> diff --git mm/debug.c mm/debug.c
> index 0461df1207cb..6a52316af839 100644
> --- mm/debug.c
> +++ mm/debug.c
> @@ -47,6 +47,7 @@ void __dump_page(struct page *page, const char *reason)
> struct address_space *mapping;
> bool page_poisoned = PagePoisoned(page);
> int mapcount;
> + char *type = "";
>
> /*
> * If struct page is poisoned don't access Page*() functions as that
> @@ -78,9 +79,9 @@ void __dump_page(struct page *page, const char *reason)
> page, page_ref_count(page), mapcount,
> page->mapping, page_to_pgoff(page));
> if (PageKsm(page))
> - pr_warn("ksm flags: %#lx(%pGp)\n", page->flags, &page->flags);
> + type = "ksm ";
> else if (PageAnon(page))
> - pr_warn("anon flags: %#lx(%pGp)\n", page->flags, &page->flags);
> + type = "anon ";
> else if (mapping) {
> if (mapping->host && mapping->host->i_dentry.first) {
> struct dentry *dentry;
> @@ -88,10 +89,11 @@ void __dump_page(struct page *page, const char *reason)
> pr_warn("%ps name:\"%pd\"\n", mapping->a_ops, dentry);
> } else
> pr_warn("%ps\n", mapping->a_ops);
> - pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);
> }
> BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
>
> + pr_warn("%sflags: %#lx(%pGp)\n", type, page->flags, &page->flags);
> +
> hex_only:
> print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
> sizeof(unsigned long), page,
>
>

\
 
 \ /
  Last update: 2020-01-14 12:03    [W:0.063 / U:21.760 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site