Re: [PATCH 2/3] mm: Allow large pages to be added to the page cache

From: kbuild test robot <lkp@intel.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: kbuild-all@01.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Kirill Shutemov <kirill@shutemov.name>,
	Song Liu <songliubraving@fb.com>,
	William Kucharski <william.kucharski@oracle.com>,
	Johannes Weiner <jweiner@fb.com>
Subject: Re: [PATCH 2/3] mm: Allow large pages to be added to the page cache
Date: Fri, 6 Sep 2019 04:56:15 +0800	[thread overview]
Message-ID: <201909060430.ZRV06fap%lkp@intel.com> (raw)
In-Reply-To: <20190905182348.5319-3-willy@infradead.org>

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Hi Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc7 next-20190904]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/mm-Add-__page_cache_alloc_order/20190906-034745
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   mm/filemap.c: In function '__add_to_page_cache_locked':
>> mm/filemap.c:863:8: error: implicit declaration of function 'compound_nr'; did you mean 'compound_order'? [-Werror=implicit-function-declaration]
      nr = compound_nr(page);
           ^~~~~~~~~~~
           compound_order
   cc1: some warnings being treated as errors

vim +863 mm/filemap.c

   840	
   841	static int __add_to_page_cache_locked(struct page *page,
   842					      struct address_space *mapping,
   843					      pgoff_t offset, gfp_t gfp_mask,
   844					      void **shadowp)
   845	{
   846		XA_STATE(xas, &mapping->i_pages, offset);
   847		int huge = PageHuge(page);
   848		struct mem_cgroup *memcg;
   849		int error;
   850		unsigned int nr = 1;
   851		void *old;
   852	
   853		VM_BUG_ON_PAGE(!PageLocked(page), page);
   854		VM_BUG_ON_PAGE(PageSwapBacked(page), page);
   855		mapping_set_update(&xas, mapping);
   856	
   857		if (!huge) {
   858			error = mem_cgroup_try_charge(page, current->mm,
   859						      gfp_mask, &memcg, false);
   860			if (error)
   861				return error;
   862			xas_set_order(&xas, offset, compound_order(page));
 > 863			nr = compound_nr(page);
   864		}
   865	
   866		page_ref_add(page, nr);
   867		page->mapping = mapping;
   868		page->index = offset;
   869	
   870		do {
   871			unsigned long exceptional = 0;
   872			unsigned int i = 0;
   873	
   874			xas_lock_irq(&xas);
   875			xas_for_each_conflict(&xas, old) {
   876				if (!xa_is_value(old))
   877					break;
   878				exceptional++;
   879				if (shadowp)
   880					*shadowp = old;
   881			}
   882			if (old) {
   883				xas_set_err(&xas, -EEXIST);
   884				break;
   885			}
   886			xas_create_range(&xas);
   887			if (xas_error(&xas))
   888				goto unlock;
   889	
   890	next:
   891			xas_store(&xas, page);
   892			if (++i < nr) {
   893				xas_next(&xas);
   894				goto next;
   895			}
   896			mapping->nrexceptional -= exceptional;
   897			mapping->nrpages += nr;
   898	
   899			/* hugetlb pages do not participate in page cache accounting */
   900			if (!huge)
   901				__mod_node_page_state(page_pgdat(page), NR_FILE_PAGES,
   902							nr);
   903	unlock:
   904			xas_unlock_irq(&xas);
   905		} while (xas_nomem(&xas, gfp_mask & GFP_RECLAIM_MASK));
   906	
   907		if (xas_error(&xas))
   908			goto error;
   909	
   910		if (!huge)
   911			mem_cgroup_commit_charge(page, memcg, false, false);
   912		trace_mm_filemap_add_to_page_cache(page);
   913		return 0;
   914	error:
   915		page->mapping = NULL;
   916		/* Leave page->index set: truncation relies upon it */
   917		if (!huge)
   918			mem_cgroup_cancel_charge(page, memcg, false);
   919		page_ref_sub(page, nr);
   920		return xas_error(&xas);
   921	}
   922	ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO);
   923	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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