From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 152/155] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge() Date: Wed, 01 Apr 2020 21:11:48 -0700 Message-ID: <20200402041148.jDH6duv6H%akpm@linux-foundation.org> References: <20200401210155.09e3b9742e1c6e732f5a7250@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:38824 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726136AbgDBELt (ORCPT ); Thu, 2 Apr 2020 00:11:49 -0400 In-Reply-To: <20200401210155.09e3b9742e1c6e732f5a7250@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, nehaagarwal@google.com, rientjes@google.com, torvalds@linux-foundation.org, vbabka@suse.cz From: Vlastimil Babka Subject: mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge() Commit f1e61557f023 ("mm: pack compound_dtor and compound_order into one word in struct page") changed compound_dtor from a pointer to an array index in order to pack it. To check if page has the hugeltbfs compound_dtor, we can just compare the index directly without fetching the function pointer. Said commit did that with PageHuge() and we can do the same with PageHeadHuge() to make the code a bit smaller and faster. Link: http://lkml.kernel.org/r/20200311172440.6988-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka Reviewed-by: Mike Kravetz Acked-by: David Rientjes Acked-by: Kirill A. Shutemov Cc: Neha Agarwal Signed-off-by: Andrew Morton --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/hugetlb.c~mm-hugetlb-remove-unnecessary-memory-fetch-in-pageheadhuge +++ a/mm/hugetlb.c @@ -1528,7 +1528,7 @@ int PageHeadHuge(struct page *page_head) if (!PageHead(page_head)) return 0; - return get_compound_page_dtor(page_head) == free_huge_page; + return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR; } /* _