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Fri, 19 Jun 2020 14:58:15 +0900 (KST) Received: from jaewon-linux.10.32.193.11 (unknown [10.253.104.229]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20200619055815epsmtip151c4e28f3e3e46d5cb2dac6afa9e9825~Z3GsV5QKK2293722937epsmtip1R; Fri, 19 Jun 2020 05:58:15 +0000 (GMT) From: Jaewon Kim To: vbabka@suse.cz, bhe@redhat.com, mgorman@techsingularity.net, minchan@kernel.org, mgorman@suse.de, hannes@cmpxchg.org, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com, ytk.lee@samsung.com, cmlaika.kim@samsung.com, Jaewon Kim Subject: [PATCH v4] page_alloc: consider highatomic reserve in watermark fast Date: Sat, 20 Jun 2020 08:59:58 +0900 Message-Id: <20200619235958.11283-1-jaewon31.kim@samsung.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpnk+LIzCtJLcpLzFFi42LZdlhTT/dH8Js4g92/VC3mrF/DZnH+wS82 i5XzzrFZrN7ka9G9eSajRe/7V0wWl3fNYbO4t+Y/q8Xkd88YLXYs3cdksezre3aL2Y19jBaP 13M78HocfvOe2WPnrLvsHptWdbJ5bPo0id3jxIzfLB7v911l8+jbsorR48yCI+wem09Xe2z9 ZefxeZNcAHdUjk1GamJKapFCal5yfkpmXrqtkndwvHO8qZmBoa6hpYW5kkJeYm6qrZKLT4Cu W2YO0PlKCmWJOaVAoYDE4mIlfTubovzSklSFjPziElul1IKUnAJDgwK94sTc4tK8dL3k/Fwr QwMDI1OgyoScjIkv1AumxFRsnrSXqYHxlV8XIyeHhICJxMZde9m7GLk4hAR2MEr8/DiLDcL5 xCgxb9dyFgjnG6PEksMT2WBanrasgKrayygx+/FkZgjnB6PEzZ2LWUGq2AS0Jd4vmMQKkhAR mM4osefeEkYQh1lgKaPE5Vs3gFZycAgL+Ev8XOEI0sAioCpx7dpNZhCbV8BW4uTb1ewQ6+Ql Vm84wAxhd3JInGtMgrBdJN6smc0KYQtLvDq+BapeSuJlfxuUXS+xZ/9fqN4GRon/HwUgbGOJ +S0LmUFOYBbQlFi/Sx8irCix8/dcRhCbWYBP4t3XHlaQEgkBXomONiGIEjWJlmdfobbKSPz9 9wyqxENifYM6SFhIIFbi25rZzBMYZWchzF/AyLiKUSy1oDg3PbXYsMAIOY42MYJTpJbZDsZJ bz/oHWJk4mA8xCjBwawkwuv8+0WcEG9KYmVValF+fFFpTmrxIUZTYGhNZJYSTc4HJum8knhD UyNjY2MLEzNzM1NjJXFeNZkLcUIC6YklqdmpqQWpRTB9TBycUg1MShLH93yrrwzU1FB9dq7/ 4KMNGdf3qedeahLWvGn8ialj9Ubm93+465pntPpYzf5kNf2Hvae08sXVThIdHWfFcmMXMobe PjRxQUqAxbaHulYb5Q5N3/be2F7xcdxG2YLOgN2vzhrpP4/bx7/D+EBwevXuB6rbxMPmil+u Fz91ZJX6r5WiPFw8b4XX+Vuxmq3NCzHzXr1Eo1GE54BMqO5VzYIGruzJHxZWL18UcdjC2vxt wtls/eNHC5NMP8+ZlT7V5+AjP68HuRM/i973Pbfoze21P5V1Go66+ppMZ/KZa7zjia1s1bkv Uof/6rCwOxXnca/Z7uomP8+yWbH8alj8d/Xwj+rNWXUzHoT3OMxWYinOSDTUYi4qTgQAtSK8 uhoEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrOLMWRmVeSWpSXmKPExsWy7bCSnO734DdxBkvOmVjMWb+GzeL8g19s FivnnWOzWL3J16J780xGi973r5gsLu+aw2Zxb81/VovJ754xWuxYuo/JYtnX9+wWsxv7GC0e r+d24PU4/OY9s8fOWXfZPTat6mTz2PRpErvHiRm/WTze77vK5tG3ZRWjx5kFR9g9Np+u9tj6 y87j8ya5AO4oLpuU1JzMstQifbsEroyJL9QLpsRUbJ60l6mB8ZVfFyMnh4SAicTTlhVsXYxc HEICuxklDp5eww6RkJF4c/4pSxcjB5AtLHH4cDFEzTdGiWXX9zOB1LAJaEu8XzCJFSQhIjCf UWLPulNgk5gFVjNKPPxwmBmkSljAV+Jmx05WEJtFQFXi2rWbYHFeAVuJk29XQ22Tl1i94QDz BEaeBYwMqxglUwuKc9Nziw0LDPNSy/WKE3OLS/PS9ZLzczcxgsNWS3MH4/ZVH/QOMTJxMB5i lOBgVhLhdf79Ik6INyWxsiq1KD++qDQntfgQozQHi5I4743ChXFCAumJJanZqakFqUUwWSYO TqkGpsUmIjEHsvYoddZpTPrwnYWRq9it67PCkZOszW+eOK5+GZ7hZPI1gunBDD6htvmPcsQ1 /shaBa/8GmS1xOvP0rwtR38E16/Z+n+NYuwUJq8w49uRzGUbuTyPGclzdelN838dyf/5yPuH SZeUvC9leu1/+8xj2vu1WieV1igz+56ayh8jHxZQn/HqydubdRPWPshgaNX9ufTSwj/PfUxt zeYcX/R33YEKI/GGxQ9Xum0RuNgZdrIvzk1IZPfy5qMyW2bobpurlLAq2+qH1dFDgbdf8L97 q+mXaVWt+Kes2E/q1s32fZfVtlx53TLj+k+R+1eyqvUVps8++c741GuTK/6HEic5KhTd0VHl 2lg5XVmJpTgj0VCLuag4EQAAGLSCygIAAA== X-CMS-MailID: 20200619055816epcas1p184da90b01aff559fe3cd690ebcd921ca 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: 20200619055816epcas1p184da90b01aff559fe3cd690ebcd921ca References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org zone_watermark_fast was introduced by commit 48ee5f3696f6 ("mm, page_alloc: shortcut watermark checks for order-0 pages"). The commit simply checks if free pages is bigger than watermark without additional 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 min, and there are only few free pages except high order atomic free. Because zone_watermark_fast passes the allocation without considering high order atomic free, normal reclaimable allocation like GFP_HIGHUSER will consume all the free pages. Then finally order-0 atomic allocation may fail on allocation. This means watermark min is not protected against non-atomic allocation. 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 accurately like cma free, we may use it. On this patch just use nr_reserved_highatomic. Additionally introduce __zone_watermark_unusable_free to factor out common parts between zone_watermark_fast and __zone_watermark_ok. This is an example of ALLOC_HARDER allocation failure using v4.19 based kernel. Binder:9343_3: page allocation failure: order:0, mode:0x480020(GFP_ATOMIC), nodemask=(null) Call trace: [] dump_stack+0xb8/0xf0 [] warn_alloc+0xd8/0x12c [] __alloc_pages_nodemask+0x120c/0x1250 [] new_slab+0x128/0x604 [] ___slab_alloc+0x508/0x670 [] __kmalloc+0x2f8/0x310 [] context_struct_to_string+0x104/0x1cc [] security_sid_to_context_core+0x74/0x144 [] security_sid_to_context+0x10/0x18 [] selinux_secid_to_secctx+0x20/0x28 [] security_secid_to_secctx+0x3c/0x70 [] binder_transaction+0xe68/0x454c Mem-Info: active_anon:102061 inactive_anon:81551 isolated_anon:0 active_file:59102 inactive_file:68924 isolated_file:64 unevictable:611 dirty:63 writeback:0 unstable:0 slab_reclaimable:13324 slab_unreclaimable:44354 mapped:83015 shmem:4858 pagetables:26316 bounce:0 free:2727 free_pcp:1035 free_cma:178 Node 0 active_anon:408244kB inactive_anon:326204kB active_file:236408kB inactive_file:275696kB unevictable:2444kB isolated(anon):0kB isolated(file):256kB mapped:332060kB dirty:252kB writeback:0kB shmem:19432kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no Normal free:10908kB min:6192kB low:44388kB high:47060kB active_anon:409160kB inactive_anon:325924kB active_file:235820kB inactive_file:276628kB unevictable:2444kB writepending:252kB present:3076096kB managed:2673676kB mlocked:2444kB kernel_stack:62512kB pagetables:105264kB bounce:0kB free_pcp:4140kB local_pcp:40kB free_cma:712kB lowmem_reserve[]: 0 0 Normal: 505*4kB (H) 357*8kB (H) 201*16kB (H) 65*32kB (H) 1*64kB (H) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 10236kB 138826 total pagecache pages 5460 pages in swap cache Swap cache stats: add 8273090, delete 8267506, find 1004381/4060142 This is an example of ALLOC_NO_WATERMARKS allocation failure using v4.14 based kernel. kswapd0: page allocation failure: order:0, mode:0x140000a(GFP_NOIO|__GFP_HIGHMEM|__GFP_MOVABLE), nodemask=(null) kswapd0 cpuset=/ mems_allowed=0 CPU: 4 PID: 1221 Comm: kswapd0 Not tainted 4.14.113-18770262-userdebug #1 Call trace: [<0000000000000000>] dump_backtrace+0x0/0x248 [<0000000000000000>] show_stack+0x18/0x20 [<0000000000000000>] __dump_stack+0x20/0x28 [<0000000000000000>] dump_stack+0x68/0x90 [<0000000000000000>] warn_alloc+0x104/0x198 [<0000000000000000>] __alloc_pages_nodemask+0xdc0/0xdf0 [<0000000000000000>] zs_malloc+0x148/0x3d0 [<0000000000000000>] zram_bvec_rw+0x410/0x798 [<0000000000000000>] zram_rw_page+0x88/0xdc [<0000000000000000>] bdev_write_page+0x70/0xbc [<0000000000000000>] __swap_writepage+0x58/0x37c [<0000000000000000>] swap_writepage+0x40/0x4c [<0000000000000000>] shrink_page_list+0xc30/0xf48 [<0000000000000000>] shrink_inactive_list+0x2b0/0x61c [<0000000000000000>] shrink_node_memcg+0x23c/0x618 [<0000000000000000>] shrink_node+0x1c8/0x304 [<0000000000000000>] kswapd+0x680/0x7c4 [<0000000000000000>] kthread+0x110/0x120 [<0000000000000000>] ret_from_fork+0x10/0x18 Mem-Info: active_anon:111826 inactive_anon:65557 isolated_anon:0\x0a active_file:44260 inactive_file:83422 isolated_file:0\x0a unevictable:4158 dirty:117 writeback:0 unstable:0\x0a slab_reclaimable:13943 slab_unreclaimable:43315\x0a mapped:102511 shmem:3299 pagetables:19566 bounce:0\x0a free:3510 free_pcp:553 free_cma:0 Node 0 active_anon:447304kB inactive_anon:262228kB active_file:177040kB inactive_file:333688kB unevictable:16632kB isolated(anon):0kB isolated(file):0kB mapped:410044kB d irty:468kB writeback:0kB shmem:13196kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no Normal free:14040kB min:7440kB low:94500kB high:98136kB reserved_highatomic:32768KB active_anon:447336kB inactive_anon:261668kB active_file:177572kB inactive_file:333768k B unevictable:16632kB writepending:480kB present:4081664kB managed:3637088kB mlocked:16632kB kernel_stack:47072kB pagetables:78264kB bounce:0kB free_pcp:2280kB local_pcp:720kB free_cma:0kB [ 4738.329607] lowmem_reserve[]: 0 0 Normal: 860*4kB (H) 453*8kB (H) 180*16kB (H) 26*32kB (H) 34*64kB (H) 6*128kB (H) 2*256kB (H) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 14232kB This is trace log which shows GFP_HIGHUSER consumes free pages right before ALLOC_NO_WATERMARKS. <...>-22275 [006] .... 889.213383: mm_page_alloc: page=00000000d2be5665 pfn=970744 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213385: mm_page_alloc: page=000000004b2335c2 pfn=970745 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213387: mm_page_alloc: page=00000000017272e1 pfn=970278 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213389: mm_page_alloc: page=00000000c4be79fb pfn=970279 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213391: mm_page_alloc: page=00000000f8a51d4f pfn=970260 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213393: mm_page_alloc: page=000000006ba8f5ac pfn=970261 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213395: mm_page_alloc: page=00000000819f1cd3 pfn=970196 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO <...>-22275 [006] .... 889.213396: mm_page_alloc: page=00000000f6b72a64 pfn=970197 order=0 migratetype=0 nr_free=3650 gfp_flags=GFP_HIGHUSER|__GFP_ZERO kswapd0-1207 [005] ...1 889.213398: mm_page_alloc: page= (null) pfn=0 order=0 migratetype=1 nr_free=3650 gfp_flags=GFP_NOWAIT|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_MOVABLE Reported-by: Yong-Taek Lee Suggested-by: Minchan Kim Signed-off-by: Jaewon Kim Acked-by: Vlastimil Babka --- v4: change description only; typo and log v3: change log in description to one having reserved_highatomic change comment in code v2: factor out common part v1: consider highatomic reserve --- mm/page_alloc.c | 66 +++++++++++++++++++++++++++---------------------- 1 file changed, 36 insertions(+), 30 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 48eb0f1410d4..fe83f88ce188 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3487,6 +3487,29 @@ static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) } ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE); +static inline long __zone_watermark_unusable_free(struct zone *z, + unsigned int order, unsigned int alloc_flags) +{ + const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); + long unusable_free = (1 << order) - 1; + + /* + * If the caller does not have rights to ALLOC_HARDER then subtract + * the high-atomic reserves. This will over-estimate the size of the + * atomic reserve but it avoids a search. + */ + if (likely(!alloc_harder)) + unusable_free += z->nr_reserved_highatomic; + +#ifdef CONFIG_CMA + /* If allocation can't use CMA areas don't use free CMA pages */ + if (!(alloc_flags & ALLOC_CMA)) + unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); +#endif + + return unusable_free; +} + /* * Return true if free base pages are above 'mark'. For high-order checks it * will return true of the order-0 watermark is reached and there is at least @@ -3502,19 +3525,12 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); /* free_pages may go negative - that's OK */ - free_pages -= (1 << order) - 1; + free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); if (alloc_flags & ALLOC_HIGH) min -= min / 2; - /* - * If the caller does not have rights to ALLOC_HARDER then subtract - * the high-atomic reserves. This will over-estimate the size of the - * atomic reserve but it avoids a search. - */ - if (likely(!alloc_harder)) { - free_pages -= z->nr_reserved_highatomic; - } else { + if (unlikely(alloc_harder)) { /* * OOM victims can try even harder than normal ALLOC_HARDER * users on the grounds that it's definitely going to be in @@ -3527,13 +3543,6 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, min -= min / 4; } - -#ifdef CONFIG_CMA - /* If allocation can't use CMA areas don't use free CMA pages */ - if (!(alloc_flags & ALLOC_CMA)) - free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES); -#endif - /* * Check watermarks for an order-0 allocation request. If these * are not met, then a high-order request also cannot go ahead @@ -3582,25 +3591,22 @@ static inline bool zone_watermark_fast(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags) { - long free_pages = zone_page_state(z, NR_FREE_PAGES); - long cma_pages = 0; + long free_pages; + long unusable_free; -#ifdef CONFIG_CMA - /* If allocation can't use CMA areas don't use free CMA pages */ - if (!(alloc_flags & ALLOC_CMA)) - cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES); -#endif + free_pages = zone_page_state(z, NR_FREE_PAGES); + unusable_free = __zone_watermark_unusable_free(z, order, alloc_flags); /* * Fast check for order-0 only. If this fails then the reserves - * need to be calculated. There is a corner case where the check - * passes but only the high-order atomic reserve are free. If - * the caller is !atomic then it'll uselessly search the free - * list. That corner case is then slower but it is harmless. + * need to be calculated. */ - if (!order && (free_pages - cma_pages) > - mark + z->lowmem_reserve[highest_zoneidx]) - return true; + if (!order) { + long fast_free = free_pages - unusable_free; + + if (fast_free > mark + z->lowmem_reserve[highest_zoneidx]) + return true; + } return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, free_pages); -- 2.17.1