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charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20220415 X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m02.sberdevices.ru (172.16.192.103) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 181606 [Nov 27 2023] X-KSMG-AntiSpam-Version: 6.0.0.2 X-KSMG-AntiSpam-Envelope-From: ddrokosov@salutedevices.com X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 4 0.3.4 720d3c21819df9b72e78f051e300e232316d302a, {Track_E25351}, {Tracking_from_domain_doesnt_match_to}, 127.0.0.199:7.1.2;p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;100.64.160.123:7.1.2;salutedevices.com:7.1.1, FromAlignment: s, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean X-KSMG-LinksScanning: Clean X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/11/27 09:57:00 #22553179 X-KSMG-AntiVirus-Status: Clean, skipped X-Rspamd-Queue-Id: 8535F40012 X-Rspam-User: X-Stat-Signature: p1xamdsdwnqjnhoz6dft3zwernf4acqb X-Rspamd-Server: rspam01 X-HE-Tag: 1701085008-342143 X-HE-Meta: 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 E+0GlxY1 ZRKb3TTfUZ2Lf3VWpqGNCNgQL5IF2JWEYw+/dDaWUXpQSoqf/gwETS4qPEg4DIpYAoDNZ6NMPXfCexIf3+nhMWPq+vhzFIJy2ZAbn6F+9OE7JkQ5ijJvimD1viVkpI6IRLVeXadS0GIjevSX67zKwV4jYU1qZ/3C0FYGUf1aBTlXOEG1Jtsu+FyD8riGeyHSNaxjbvXAfDRhH8TusGjzK2Zi+78DRGKorYWhDFofOQiPDcPjKLkJRHXRu9Lperw0hqqOMRU61s/tUKpqTAw36CmzjwhSgfM8FcHe1JtTrohOwEACYGbEHNFea/V3aokrrevOdU1H+XruFcTl8Xg23QbhkjgKTpbaUtvxw8ykCAsAx354X8jXPeLvCke/ZjL6vau88dmXxpeZA5yU= 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: List-Subscribe: List-Unsubscribe: On Mon, Nov 27, 2023 at 10:33:49AM +0100, Michal Hocko wrote: > On Thu 23-11-23 22:39:37, Dmitry Rokosov wrote: > > The shrink_memcg flow plays a crucial role in memcg reclamation. > > Currently, it is not possible to trace this point from non-direct > > reclaim paths. However, direct reclaim has its own tracepoint, so there > > is no issue there. In certain cases, when debugging memcg pressure, > > developers may need to identify all potential requests for memcg > > reclamation including kswapd(). The patchset introduces the tracepoints > > mm_vmscan_memcg_shrink_{begin|end}() to address this problem. > > > > Example of output in the kswapd context (non-direct reclaim): > > kswapd0-39 [001] ..... 240.356378: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.356396: mm_vmscan_memcg_shrink_end: nr_reclaimed=0 memcg=16 > > kswapd0-39 [001] ..... 240.356420: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.356454: mm_vmscan_memcg_shrink_end: nr_reclaimed=1 memcg=16 > > kswapd0-39 [001] ..... 240.356479: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.356506: mm_vmscan_memcg_shrink_end: nr_reclaimed=4 memcg=16 > > kswapd0-39 [001] ..... 240.356525: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.356593: mm_vmscan_memcg_shrink_end: nr_reclaimed=11 memcg=16 > > kswapd0-39 [001] ..... 240.356614: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.356738: mm_vmscan_memcg_shrink_end: nr_reclaimed=25 memcg=16 > > kswapd0-39 [001] ..... 240.356790: mm_vmscan_memcg_shrink_begin: order=0 gfp_flags=GFP_KERNEL memcg=16 > > kswapd0-39 [001] ..... 240.357125: mm_vmscan_memcg_shrink_end: nr_reclaimed=53 memcg=16 > > In the previous version I have asked why do we need this specific > tracepoint when we already do have trace_mm_vmscan_lru_shrink_{in}active > which already give you a very good insight. That includes the number of > reclaimed pages but also more. I do see that we do not include memcg id > of the reclaimed LRU, but that shouldn't be a big problem to add, no? >From my point of view, memcg reclaim includes two points: LRU shrink and slab shrink, as mentioned in the vmscan.c file. static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc) ... reclaimed = sc->nr_reclaimed; scanned = sc->nr_scanned; shrink_lruvec(lruvec, sc); shrink_slab(sc->gfp_mask, pgdat->node_id, memcg, sc->priority); ... So, both of these operations are important for understanding whether memcg reclaiming was successful or not, as well as its effectiveness. I believe it would be beneficial to summarize them, which is why I have created new tracepoints. -- Thank you, Dmitry