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Fri, 12 Jun 2020 16:03:43 +0900 (KST) Received: from [10.253.104.82] (unknown [10.253.104.82]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20200612070342epsmtip2eb08743712636e0d0a7406dc9771a66f~Xue1ZVjIH0095700957epsmtip2D; Fri, 12 Jun 2020 07:03:42 +0000 (GMT) Subject: Re: [PATCH] page_alloc: consider highatomic reserve in wmartermark fast To: Minchan Kim Cc: mgorman@techsingularity.net, mgorman@suse.de, hannes@cmpxchg.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com, ytk.lee@samsung.com, cmlaika.kim@samsung.com From: Jaewon Kim Message-ID: <5EE328CD.2060100@samsung.com> Date: Fri, 12 Jun 2020 16:03:41 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <20200612065523.GA92598@google.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrLJsWRmVeSWpSXmKPExsWy7bCmge55jcdxBvseWlvMWb+GzWLlvHNs Fqs3+Vp0b57JaHF51xw2i3tr/rNaTH73jNFix9J9TBbLvr5nt3i8ntuBy+Pwm/fMHjtn3WX3 2LSqk81j06dJ7B4nZvxm8ejbsorRY/Ppao+tv+w8Pm+SC+CMyrHJSE1MSS1SSM1Lzk/JzEu3 VfIOjneONzUzMNQ1tLQwV1LIS8xNtVVy8QnQdcvMAbpSSaEsMacUKBSQWFyspG9nU5RfWpKq kJFfXGKrlFqQklNgaFCgV5yYW1yal66XnJ9rZWhgYGQKVJmQk3Fg8XmWgrbUiofTZrE1MG4L 7WLk5JAQMJGY1TCXvYuRi0NIYAejxKwTf5khnE+MEj+OPGaBcD4zSpxpvc4C0/L94jRWiMQu Rol7J9dBVb1llPiy/QETSJWwQJDEmpvTmUFsEQEViT9P/zGCFDEL3GaU+H9xMliCTUBb4v2C SUCjODh4BbQkfm03BgmzCKhKTJi2ih3EFhWIkNgx9yMjiM0rIChxcuYTsCs4BQwk9uw7AVbD LCAv0bx1NtjdEgJrOSQmbZnACHGqi8TL5Q2sELawxKvjW9ghbCmJz+/2skHY9RJ79v9lhrAb gI77KABhG0vMb1nIDHIbs4CmxPpd+hBhRYmdv+cyQuzlk3j3tQfsfAkBXomONiGIEjWJlmdf obbKSPz99wzK9pDY1vwbGrx/GCU2dnczT2BUmIXktVlI3pmFsHkBI/MqRrHUguLc9NRiwwJT 5CjexAhOt1qWOxinv/2gd4iRiYPxEKMEB7OSCK+g+MM4Id6UxMqq1KL8+KLSnNTiQ4ymwACe yCwlmpwPTPh5JfGGpkbGxsYWJmbmZqbGSuK8TtYX4oQE0hNLUrNTUwtSi2D6mDg4pRqY5Ka4 JG66FNTD8v7sEQeXTTZRIl3TIh+KMxmLNqt5GfDmnp33SoTv7ZV1G6YmsLacTtJyuCrq0BEe 8dOi7eA+29c5Uhc57rRcKo347bO7a5atQPDNOLWdGyYusdryX0sqSjs2zV8rrPvR7idnirIs l22Ttf7/NFt8utyDqCU2P6rs/hycGfbV+93bz5/fXrSVvV+2PujP5N0Oi6/+5+R99dm48pPZ t4NKbcJtojVvl9+aJPxdUXrSVPYZBlO2xcn7+plkthpsX1QwQUK59uxWHvu1PwL6D8wo6udl fRg0IaK3xzpbRoPlwqeM+QFyyge1eUSrJzDMcI9cYBx4y0DjxH6nsHcx6/Q1LdeKfFFSYinO SDTUYi4qTgQAfCTXC0AEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrHLMWRmVeSWpSXmKPExsWy7bCSvO55jcdxBmceyVjMWb+GzWLlvHNs Fqs3+Vp0b57JaHF51xw2i3tr/rNaTH73jNFix9J9TBbLvr5nt3i8ntuBy+Pwm/fMHjtn3WX3 2LSqk81j06dJ7B4nZvxm8ejbsorRY/Ppao+tv+w8Pm+SC+CM4rJJSc3JLEst0rdL4Mo4sPg8 S0FbasXDabPYGhi3hXYxcnJICJhIfL84jbWLkYtDSGAHo8SKtZtZIBIyEm/OPwWyOYBsYYnD h4shal4zSiy4NoUJpEZYIEhizc3pzCC2iICKxJ+n/xghiv4wSkxZvgFsKrPAbUaJGW+vgHWw CWhLvF8wiRVkKq+AlsSv7cYgYRYBVYkJ01axg9iiAhESq9ddAxvKKyAocXLmE7CDOAUMJPbs OwFWwyygLvFn3iVmCFteonnrbOYJjIKzkLTMQlI2C0nZAkbmVYySqQXFuem5xYYFRnmp5XrF ibnFpXnpesn5uZsYwVGkpbWDcc+qD3qHGJk4GA8xSnAwK4nwCoo/jBPiTUmsrEotyo8vKs1J LT7EKM3BoiTO+3XWwjghgfTEktTs1NSC1CKYLBMHp1QDU1lb4D8P1tTP054s+aXFMe+27eWX wj3Nr+8nvW7kK7q4ad8sluSCeQ4ayV7OJf1Hz6RcbhOabyHv/V9xyryfl/xbDtWfUtG+Xxd2 O84vssNW7rbjifdPe1hKlb/qFFcuF9hkmVTKrMm8a8bFKeVqXKVXtbe8XRry/+ymUMuVsQcS TyhWKqnP+iBUXVP/UGxlmHUv6z3/mtXPvy9dvvRh/o0s9QfJ8xynhTifi3n8I3jWv20iscEH IqRik3IZGa9lrjqabp+S5P+l70pG4g7RE8tnrFi1uOWbJE9Hpc2mU4kSz/erbdmzabqNisnR qQVuHI/Uj7qGrTBYvnBRxMcspeP1V50C7pqnv+11KbuZqsRSnJFoqMVcVJwIAAuKKKcRAwAA X-CMS-MailID: 20200612070343epcas1p4b9e9e2900c29e0512b2ba34c603b1274 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20200609095139epcas1p17f9c213de6daf25fe848921bc70481c0 References: <20200609095128.8112-1-jaewon31.kim@samsung.com> <20200610012112.GA239587@google.com> <5EE1F134.4090001@samsung.com> <20200612065523.GA92598@google.com> X-Rspamd-Queue-Id: 0DB9F100E690B X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2020=EB=85=84 06=EC=9B=94 12=EC=9D=BC 15:55, Minchan Kim wrote: > On Thu, Jun 11, 2020 at 05:54:12PM +0900, Jaewon Kim wrote: >> >> On 2020=EB=85=84 06=EC=9B=94 10=EC=9D=BC 10:21, Minchan Kim wrote: >>> Hi Jaewon, >>> >>> On Tue, Jun 09, 2020 at 06:51:28PM +0900, Jaewon Kim wrote: >>>> zone_watermark_fast was introduced by commit 48ee5f3696f6 ("mm, >>>> page_alloc: shortcut watermark checks for order-0 pages"). The commi= t >>>> simply checks if free pages is bigger than watermark without additio= nal >>>> calculation such like reducing watermark. >>>> >>>> It considered free cma pages but it did not consider highatomic >>>> reserved. This may incur exhaustion of free pages except high order >>>> atomic free pages. >>>> >>>> Assume that reserved_highatomic pageblock is bigger than watermark m= in, >>>> and there are only few free pages except high order atomic free. Bec= ause >>>> zone_watermark_fast passes the allocation without considering high o= rder >>>> atomic free, normal reclaimable allocation like GFP_HIGHUSER will >>>> consume all the free pages. Then finally order-0 atomic allocation m= ay >>>> fail on allocation. >>>> >>>> This means watermark min is not protected against non-atomic allocat= ion. >>>> The order-0 atomic allocation with ALLOC_HARDER unwantedly can be >>>> failed. Additionally the __GFP_MEMALLOC allocation with >>>> ALLOC_NO_WATERMARKS also can be failed. >>>> >>>> To avoid the problem, zone_watermark_fast should consider highatomic >>>> reserve. If the actual size of high atomic free is counted accuratel= y >>>> like cma free, we may use it. On this patch just use >>>> nr_reserved_highatomic. >>>> >>>> This is trace log which shows GFP_HIGHUSER consumes free pages right >>>> before ALLOC_NO_WATERMARKS. >>>> >>>> <...>-22275 [006] .... 889.213383: mm_page_alloc: page=3D0000000= 0d2be5665 pfn=3D970744 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213385: mm_page_alloc: page=3D0000000= 04b2335c2 pfn=3D970745 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213387: mm_page_alloc: page=3D0000000= 0017272e1 pfn=3D970278 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213389: mm_page_alloc: page=3D0000000= 0c4be79fb pfn=3D970279 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213391: mm_page_alloc: page=3D0000000= 0f8a51d4f pfn=3D970260 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213393: mm_page_alloc: page=3D0000000= 06ba8f5ac pfn=3D970261 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213395: mm_page_alloc: page=3D0000000= 0819f1cd3 pfn=3D970196 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> <...>-22275 [006] .... 889.213396: mm_page_alloc: page=3D0000000= 0f6b72a64 pfn=3D970197 order=3D0 migratetype=3D0 nr_free=3D3650 gfp_flags= =3DGFP_HIGHUSER|__GFP_ZERO >>>> kswapd0-1207 [005] ...1 889.213398: mm_page_alloc: page=3D (null)= pfn=3D0 order=3D0 migratetype=3D1 nr_free=3D3650 gfp_flags=3DGFP_NOWAIT|= __GFP_HIGHMEM|__GFP_NOWARN|__GFP_MOVABLE >>>> >>>> This is an example of ALLOC_HARDER allocation failure. >>>> >>>> <4>[ 6207.637280] [3: Binder:9343_3:22875] Binder:9343_3: page all= ocation failure: order:0, mode:0x480020(GFP_ATOMIC), nodemask=3D(null) >>>> <4>[ 6207.637311] [3: Binder:9343_3:22875] Call trace: >>>> <4>[ 6207.637346] [3: Binder:9343_3:22875] [] du= mp_stack+0xb8/0xf0 >>>> <4>[ 6207.637356] [3: Binder:9343_3:22875] [] wa= rn_alloc+0xd8/0x12c >>>> <4>[ 6207.637365] [3: Binder:9343_3:22875] [] __= alloc_pages_nodemask+0x120c/0x1250 >>>> <4>[ 6207.637374] [3: Binder:9343_3:22875] [] ne= w_slab+0x128/0x604 >>>> <4>[ 6207.637381] [3: Binder:9343_3:22875] [] __= _slab_alloc+0x508/0x670 >>>> <4>[ 6207.637387] [3: Binder:9343_3:22875] [] __= kmalloc+0x2f8/0x310 >>>> <4>[ 6207.637396] [3: Binder:9343_3:22875] [] co= ntext_struct_to_string+0x104/0x1cc >>>> <4>[ 6207.637404] [3: Binder:9343_3:22875] [] se= curity_sid_to_context_core+0x74/0x144 >>>> <4>[ 6207.637412] [3: Binder:9343_3:22875] [] se= curity_sid_to_context+0x10/0x18 >>>> <4>[ 6207.637421] [3: Binder:9343_3:22875] [] se= linux_secid_to_secctx+0x20/0x28 >>>> <4>[ 6207.637430] [3: Binder:9343_3:22875] [] se= curity_secid_to_secctx+0x3c/0x70 >>>> <4>[ 6207.637442] [3: Binder:9343_3:22875] [] bi= nder_transaction+0xe68/0x454c >>>> <4>[ 6207.637569] [3: Binder:9343_3:22875] Mem-Info: >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] active_anon:102061 inac= tive_anon:81551 isolated_anon:0 >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] active_file:59102 inac= tive_file:68924 isolated_file:64 >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] unevictable:611 dirty:= 63 writeback:0 unstable:0 >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] slab_reclaimable:13324= slab_unreclaimable:44354 >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] mapped:83015 shmem:485= 8 pagetables:26316 bounce:0 >>>> <4>[ 6207.637595] [3: Binder:9343_3:22875] free:2727 free_pcp:103= 5 free_cma:178 >>>> <4>[ 6207.637616] [3: Binder:9343_3:22875] Node 0 active_anon:4082= 44kB inactive_anon:326204kB active_file:236408kB inactive_file:275696kB u= nevictable:2444kB isolated(anon):0kB isolated(file):256kB mapped:332060kB= dirty:252kB writeback:0kB shmem:19432kB writeback_tmp:0kB unstable:0kB a= ll_unreclaimable? no >>>> <4>[ 6207.637627] [3: Binder:9343_3:22875] Normal free:10908kB min= :6192kB low:44388kB high:47060kB active_anon:409160kB inactive_anon:32592= 4kB active_file:235820kB inactive_file:276628kB unevictable:2444kB writep= ending:252kB present:3076096kB managed:2673676kB mlocked:2444kB kernel_st= ack:62512kB pagetables:105264kB bounce:0kB free_pcp:4140kB local_pcp:40kB= free_cma:712kB >>>> <4>[ 6207.637632] [3: Binder:9343_3:22875] lowmem_reserve[]: 0 0 >>>> <4>[ 6207.637637] [3: Binder:9343_3:22875] Normal: 505*4kB (H) 357= *8kB (H) 201*16kB (H) 65*32kB (H) 1*64kB (H) 0*128kB 0*256kB 0*512kB 0*10= 24kB 0*2048kB 0*4096kB =3D 10236kB >>>> <4>[ 6207.637655] [3: Binder:9343_3:22875] 138826 total pagecache = pages >>>> <4>[ 6207.637663] [3: Binder:9343_3:22875] 5460 pages in swap cach= e >>>> <4>[ 6207.637668] [3: Binder:9343_3:22875] Swap cache stats: add 8= 273090, delete 8267506, find 1004381/4060142 >>>> >>>> This is an example of ALLOC_NO_WATERMARKS allocation failure. >>>> >>>> <6>[ 156.701551] [4: kswapd0: 1209] kswapd0 cpuset=3D/ mems= _allowed=3D0 >>>> <4>[ 156.701563] [4: kswapd0: 1209] CPU: 4 PID: 1209 Comm: = kswapd0 Tainted: G W 4.14.113-18113966 #1 >>>> <4>[ 156.701572] [4: kswapd0: 1209] Call trace: >>>> <4>[ 156.701605] [4: kswapd0: 1209] [<0000000000000000>] du= mp_stack+0x68/0x90 >>>> <4>[ 156.701612] [4: kswapd0: 1209] [<0000000000000000>] wa= rn_alloc+0x104/0x198 >>>> <4>[ 156.701617] [4: kswapd0: 1209] [<0000000000000000>] __= alloc_pages_nodemask+0xdc0/0xdf0 >>>> <4>[ 156.701623] [4: kswapd0: 1209] [<0000000000000000>] zs= _malloc+0x148/0x3d0 >>>> <4>[ 156.701630] [4: kswapd0: 1209] [<0000000000000000>] zr= am_bvec_rw+0x250/0x568 >>>> <4>[ 156.701634] [4: kswapd0: 1209] [<0000000000000000>] zr= am_rw_page+0x8c/0xe0 >>>> <4>[ 156.701640] [4: kswapd0: 1209] [<0000000000000000>] bd= ev_write_page+0x70/0xbc >>>> <4>[ 156.701645] [4: kswapd0: 1209] [<0000000000000000>] __= swap_writepage+0x58/0x37c >>>> <4>[ 156.701649] [4: kswapd0: 1209] [<0000000000000000>] sw= ap_writepage+0x40/0x4c >>>> <4>[ 156.701654] [4: kswapd0: 1209] [<0000000000000000>] sh= rink_page_list+0xc3c/0xf54 >>>> <4>[ 156.701659] [4: kswapd0: 1209] [<0000000000000000>] sh= rink_inactive_list+0x2b0/0x61c >>>> <4>[ 156.701664] [4: kswapd0: 1209] [<0000000000000000>] sh= rink_node_memcg+0x23c/0x618 >>>> <4>[ 156.701668] [4: kswapd0: 1209] [<0000000000000000>] sh= rink_node+0x1c8/0x304 >>>> <4>[ 156.701673] [4: kswapd0: 1209] [<0000000000000000>] ks= wapd+0x680/0x7c4 >>>> <4>[ 156.701679] [4: kswapd0: 1209] [<0000000000000000>] kt= hread+0x110/0x120 >>>> <4>[ 156.701684] [4: kswapd0: 1209] [<0000000000000000>] re= t_from_fork+0x10/0x18 >>>> <4>[ 156.701689] [4: kswapd0: 1209] Mem-Info: >>>> <4>[ 156.701712] [4: kswapd0: 1209] active_anon:88690 inact= ive_anon:88630 isolated_anon:0 >>>> <4>[ 156.701712] [4: kswapd0: 1209] active_file:99173 inac= tive_file:169305 isolated_file:32 >>>> <4>[ 156.701712] [4: kswapd0: 1209] unevictable:48292 dirt= y:538 writeback:38 unstable:0 >>>> <4>[ 156.701712] [4: kswapd0: 1209] slab_reclaimable:15131= slab_unreclaimable:47762 >>>> <4>[ 156.701712] [4: kswapd0: 1209] mapped:274654 shmem:28= 24 pagetables:25088 bounce:0 >>>> <4>[ 156.701712] [4: kswapd0: 1209] free:2489 free_pcp:444= free_cma:3 >>>> <4>[ 156.701728] [4: kswapd0: 1209] Node 0 active_anon:3547= 60kB inactive_anon:354520kB active_file:396692kB inactive_file:677220kB u= nevictable:193168kB isolated(anon):0kB isolated(file):128kB mapped:109861= 6kB dirty:2152kB writeback:152kB shmem:11296kB writeback_tmp:0kB unstable= :0kB all_unreclaimable? no >>>> <4>[ 156.701738] [4: kswapd0: 1209] Normal free:9956kB min:= 7428kB low:93440kB high:97032kB active_anon:355176kB inactive_anon:354580= kB active_file:396196kB inactive_file:677284kB unevictable:193168kB write= pending:2304kB present:4081664kB managed:3593324kB mlocked:193168kB kerne= l_stack:55008kB pagetables:100352kB bounce:0kB free_pcp:1776kB local_pcp:= 656kB free_cma:12kB >>>> <4>[ 156.701741] [4: kswapd0: 1209] lowmem_reserve[]: 0 0 >>>> <4>[ 156.701747] [4: kswapd0: 1209] Normal: 196*4kB (H) 141= *8kB (H) 109*16kB (H) 63*32kB (H) 20*64kB (H) 8*128kB (H) 2*256kB (H) 1*5= 12kB (H) 0*1024kB 0*2048kB 0*4096kB =3D 9000kB >>>> >>>> Signed-off-by: Jaewon Kim >>>> Reported-by: Yong-Taek Lee >>>> --- >>>> mm/page_alloc.c | 13 +++++++++++-- >>>> 1 file changed, 11 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>>> index 13cc653122b7..00869378d387 100644 >>>> --- a/mm/page_alloc.c >>>> +++ b/mm/page_alloc.c >>>> @@ -3553,6 +3553,11 @@ static inline bool zone_watermark_fast(struct= zone *z, unsigned int order, >>>> { >>>> long free_pages =3D zone_page_state(z, NR_FREE_PAGES); >>>> long cma_pages =3D 0; >>>> + long highatomic =3D 0; >>>> + const bool alloc_harder =3D (alloc_flags & (ALLOC_HARDER|ALLOC_OOM= )); >>>> + >>>> + if (likely(!alloc_harder)) >>>> + highatomic =3D z->nr_reserved_highatomic; >>>> =20 >>>> #ifdef CONFIG_CMA >>>> /* If allocation can't use CMA areas don't use free CMA pages */ >>>> @@ -3567,8 +3572,12 @@ static inline bool zone_watermark_fast(struct= zone *z, unsigned int order, >>>> * the caller is !atomic then it'll uselessly search the free >>>> * list. That corner case is then slower but it is harmless. >>>> */ >>>> - if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[= classzone_idx]) >>>> - return true; >>>> + if (!order) { >>>> + long fast_free =3D free_pages - cma_pages - highatomic; >>> With your change, it seems we share most code for getting free_pages=20 >>> between zone_watermark_fast and __zone_watermark_ok. Only difference >>> between them is min calculation. If so, can we share most code betwee= n >>> them via introducing like __zone_watermark_free static inline functio= n? >>> So, we didn't miss one place in future if we change something. >>> >> Hello thank you for your comment. >> >> I tried to share some code. >> Because __zone_watermark_ok gets free pages as argument, >> I just could make a function calculating unusable free. >> >> static inline long __zone_watermark_unusable_free(struct zone *z, >> unsigned int alloc= _flags) >> >> on zone_watermark_fast >> free_pages -=3D __zone_watermark_unusable_free(z, alloc_flags); >> >> on __zone_watermark_ok >> free_pages -=3D __zone_watermark_unusable_free(z, alloc_flags); > Don't you need order argument? Yes I actually I also took a consideration for it. If I keep existing logic of zone_watermark_fast, following code in __zone_watermark_ok is not needed for __zone_watermark_= unusable_free free_pages -=3D (1 << order) - 1; But if __zone_watermark_unusable_free should return all unusable free, the order size should be included. Seems not critical but I want to hear opensource opinion. Thank you > > Anyway, it looks good to me. > Thanks! > >