From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933004AbdELJS4 (ORCPT ); Fri, 12 May 2017 05:18:56 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60127 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932610AbdELJSs (ORCPT ); Fri, 12 May 2017 05:18:48 -0400 To: linux-mm@kvack.org, Linux Kernel Mailing List From: Christian Borntraeger Subject: mm: page allocation failures in swap_duplicate -> add_swap_count_continuation Date: Fri, 12 May 2017 11:18:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 17051209-0020-0000-0000-00000BECF9B6 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007050; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000211; SDB=6.00859436; UDB=6.00426014; IPR=6.00639019; BA=6.00005345; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015423; XFM=3.00000015; UTC=2017-05-12 09:18:45 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17051209-0021-0000-0000-00005C4A1BCC Message-Id: <772d81b0-df36-8644-41ca-dc13d0c0f2b5@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-12_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705120174 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Folks, recently I have seen page allocation failures during paging in the paging code: e.g. May 05 21:36:53 kernel: Call Trace: May 05 21:36:53 kernel: ([<0000000000112f62>] show_trace+0x62/0x78) May 05 21:36:53 kernel: [<0000000000113050>] show_stack+0x68/0xe0 May 05 21:36:53 kernel: [<00000000004fb97e>] dump_stack+0x7e/0xb0 May 05 21:36:53 kernel: [<0000000000299262>] warn_alloc+0xf2/0x190 May 05 21:36:53 kernel: [<000000000029a25a>] __alloc_pages_nodemask+0xeda/0xfe0 May 05 21:36:53 kernel: [<00000000002fa570>] alloc_pages_current+0xb8/0x170 May 05 21:36:53 kernel: [<00000000002f03fc>] add_swap_count_continuation+0x3c/0x280 May 05 21:36:53 kernel: [<00000000002f068c>] swap_duplicate+0x4c/0x80 May 05 21:36:53 kernel: [<00000000002dfbfa>] try_to_unmap_one+0x372/0x578 May 05 21:36:53 kernel: [<000000000030131a>] rmap_walk_ksm+0x14a/0x1d8 May 05 21:36:53 kernel: [<00000000002e0d60>] try_to_unmap+0x140/0x170 May 05 21:36:53 kernel: [<00000000002abc9c>] shrink_page_list+0x944/0xad8 May 05 21:36:53 kernel: [<00000000002ac720>] shrink_inactive_list+0x1e0/0x5b8 May 05 21:36:53 kernel: [<00000000002ad642>] shrink_node_memcg+0x5e2/0x800 May 05 21:36:53 kernel: [<00000000002ad954>] shrink_node+0xf4/0x360 May 05 21:36:53 kernel: [<00000000002aeb00>] kswapd+0x330/0x810 May 05 21:36:53 kernel: [<0000000000189f14>] kthread+0x144/0x168 May 05 21:36:53 kernel: [<00000000008011ea>] kernel_thread_starter+0x6/0xc May 05 21:36:53 kernel: [<00000000008011e4>] kernel_thread_starter+0x0/0xc This seems to be new in 4.11 but the relevant code did not seem to have changed. Something like this diff --git a/mm/swapfile.c b/mm/swapfile.c index 1781308..b2dd53e 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3039,7 +3039,7 @@ int swap_duplicate(swp_entry_t entry) int err = 0; while (!err && __swap_duplicate(entry, 1) == -ENOMEM) - err = add_swap_count_continuation(entry, GFP_ATOMIC); + err = add_swap_count_continuation(entry, GFP_ATOMIC | __GFP_NOWARN); return err; } seems not appropriate, because this code does not know if the caller can handle returned errors. Would something like the following (white space damaged cut'n'paste be ok? (the try_to_unmap_one change looks fine, not sure if copy_one_pte does the right thing) diff --git a/include/linux/swap.h b/include/linux/swap.h index 45e91dd..4577494 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -391,7 +391,7 @@ extern swp_entry_t get_swap_page_of_type(int); extern int get_swap_pages(int n, swp_entry_t swp_entries[]); extern int add_swap_count_continuation(swp_entry_t, gfp_t); extern void swap_shmem_alloc(swp_entry_t); -extern int swap_duplicate(swp_entry_t); +extern int swap_duplicate(swp_entry_t, gfp_t); extern int swapcache_prepare(swp_entry_t); extern void swap_free(swp_entry_t); extern void swapcache_free(swp_entry_t); @@ -447,7 +447,7 @@ static inline void swap_shmem_alloc(swp_entry_t swp) { } -static inline int swap_duplicate(swp_entry_t swp) +int swap_duplicate(swp_entry_t entry, gfp_t gfp_mask) { return 0; } diff --git a/mm/memory.c b/mm/memory.c index 235ba51..3ae6f33 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -898,7 +898,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, swp_entry_t entry = pte_to_swp_entry(pte); if (likely(!non_swap_entry(entry))) { - if (swap_duplicate(entry) < 0) + if (swap_duplicate(entry, __GFP_NOWARN) < 0) return entry.val; /* make sure dst_mm is on swapoff's mmlist. */ diff --git a/mm/rmap.c b/mm/rmap.c index f683801..777feb6 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1433,7 +1433,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, goto discard; } - if (swap_duplicate(entry) < 0) { + if (swap_duplicate(entry, __GFP_NOWARN) < 0) { set_pte_at(mm, address, pvmw.pte, pteval); ret = SWAP_FAIL; page_vma_mapped_walk_done(&pvmw); diff --git a/mm/swapfile.c b/mm/swapfile.c index 1781308..1f86268 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3034,12 +3034,12 @@ void swap_shmem_alloc(swp_entry_t entry) * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which * might occur if a page table entry has got corrupted. */ -int swap_duplicate(swp_entry_t entry) +int swap_duplicate(swp_entry_t entry, gfp_t gfp_mask) { int err = 0; while (!err && __swap_duplicate(entry, 1) == -ENOMEM) - err = add_swap_count_continuation(entry, GFP_ATOMIC); + err = add_swap_count_continuation(entry, GFP_ATOMIC | gfp_mask); return err; }