Messages in this thread | | | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv2, RFC 08/30] thp, mm: rewrite add_to_page_cache_locked() to support huge pages | Date | Fri, 15 Mar 2013 17:05:22 +0200 (EET) |
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Hillf Danton wrote: > On Fri, Mar 15, 2013 at 9:50 PM, Kirill A. Shutemov > <kirill.shutemov@linux.intel.com> wrote: > > Hillf Danton wrote: > >> On Fri, Mar 15, 2013 at 9:23 PM, Kirill A. Shutemov > >> <kirill.shutemov@linux.intel.com> wrote: > >> > Hillf Danton wrote: > >> >> On Fri, Mar 15, 2013 at 1:50 AM, Kirill A. Shutemov > >> >> <kirill.shutemov@linux.intel.com> wrote: > >> >> > + page_cache_get(page); > >> >> > + spin_lock_irq(&mapping->tree_lock); > >> >> > + page->mapping = mapping; > >> >> > + page->index = offset; > >> >> > + error = radix_tree_insert(&mapping->page_tree, offset, page); > >> >> > + if (unlikely(error)) > >> >> > + goto err; > >> >> > + if (PageTransHuge(page)) { > >> >> > + int i; > >> >> > + for (i = 1; i < HPAGE_CACHE_NR; i++) { > >> >> struct page *tail = page + i; to easy reader > >> >> > >> >> > + page_cache_get(page + i); > >> >> s/page_cache_get/get_page_foll/ ? > >> > > >> > Why? > >> > > >> see follow_trans_huge_pmd() please. > > > > Sorry, I fail to see how follow_trans_huge_pmd() is relevant here. > > Could you elaborate? > > > Lets see the code > > page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; > //page is tail now > VM_BUG_ON(!PageCompound(page)); > if (flags & FOLL_GET) > get_page_foll(page); > //raise page count with the foll function > > thus I raised question.
get_page_foll() is designed to be part of follow_page*() call chain. get_page() can handle compound pages properly.
-- Kirill A. Shutemov
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