From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="k1hQ6ZJB" Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34DDC12B for ; Sat, 25 Nov 2023 09:47:45 -0800 (PST) Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-5bddc607b45so3641374a12.0 for ; Sat, 25 Nov 2023 09:47:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1700934464; x=1701539264; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=9pQvrE1VjbnX/y6ByGIqcRM35RSO1PuZh7mCElTQgyQ=; b=k1hQ6ZJB1bmgJmzfADagmXFnKtyI3Fwya/qNFf4Gc8YrLkkmHr0Rxm31cII4p8d4li loEQpBJs/RAXM2iJJI09Pl+VKEHeSD9G68EjF8UZAwQb0MoCxr94pVXiW3hWkwE+8g2A oR+zKUeUcuaPnsCgzJEMDJEqBvu67m9qF3j7KwAbT5l80gc0GcgVwo/bTrGO6EIh+uUN FCuUcTvY1Pnh4lqFy6eDHiF5lfwFPn82iHpHeboLDXv1xlLcrYKJ3wUGRDp05gvZ4h3P Pa/5O6yDWC0ebIt8htKbVbcJAnC4In3OH+xGnIOgtKWun5hqTKQ5ASAKmFDIoSFqX3M9 uFIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700934464; x=1701539264; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9pQvrE1VjbnX/y6ByGIqcRM35RSO1PuZh7mCElTQgyQ=; b=FDEWVkHOKQud7CBjyrSIfj54CMhJT1kdqkBYJ/jfKB68rfQY47iW7xW1dX4RxU8fNk vmE6oF59bZxAABw4NVnI2W4ydQCN+//9p5Z5wt8e/QCy7lSd6mbAuBbcMybNV8tn7bq8 3ubhAY+S1ABDyMX57xm0vj2xMjwnCM4CTEYfcS/+NgmEUmBCz4jnEzUw6/IfIrqY0h55 pctrl1IIEzv2TzIJ0AXXOJHFzwUPQzRS9tCAYBrXMCno7yO+JqrTvvUKiI+2+kP/1IbU g9X+EadE9WscojIy3GbR/bYKROJERxzhirOcQSPs5NAZyazh6rtuDVCQxqggS48+GOga kXDw== X-Gm-Message-State: AOJu0YyfrJLbfD2MKPF/J0xmVWsniREtY8dcoOj/MIqp+RB/aofveErg Ho216PRm8hYI56vyxlvgx1TEHsraTmFXqQ== X-Google-Smtp-Source: AGHT+IFflWgX+Gg7h8fTMTF6SpzYKnQOYwGbJCZ4v+j1BmllVH1kpuMX3VxlWRmMPr/i4NyYau2+euR5tvKkyw== X-Received: from shakeelb.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:262e]) (user=shakeelb job=sendgmr) by 2002:a63:d209:0:b0:5be:1194:9c0b with SMTP id a9-20020a63d209000000b005be11949c0bmr1039251pgg.3.1700934464725; Sat, 25 Nov 2023 09:47:44 -0800 (PST) Date: Sat, 25 Nov 2023 17:47:42 +0000 In-Reply-To: <20231123193937.11628-3-ddrokosov@salutedevices.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231123193937.11628-1-ddrokosov@salutedevices.com> <20231123193937.11628-3-ddrokosov@salutedevices.com> Message-ID: <20231125174742.n3ybfum53yd27bo7@google.com> Subject: Re: [PATCH v3 2/2] mm: memcg: introduce new event to trace shrink_memcg From: Shakeel Butt To: Dmitry Rokosov Cc: rostedt@goodmis.org, mhiramat@kernel.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, mhocko@suse.com, akpm@linux-foundation.org, kernel@sberdevices.ru, rockosov@gmail.com, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, Nov 23, 2023 at 10:39:37PM +0300, 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 > > Signed-off-by: Dmitry Rokosov Acked-by: Shakeel Butt