From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 649A4CD4F3C for ; Sat, 16 May 2026 21:04:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 44CF96B0095; Sat, 16 May 2026 17:04:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3FE466B0093; Sat, 16 May 2026 17:04:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29D6A6B0095; Sat, 16 May 2026 17:04:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 1D5AA6B0092 for ; Sat, 16 May 2026 17:04:11 -0400 (EDT) Received: from smtpin13.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id CF081140315 for ; Sat, 16 May 2026 21:04:10 +0000 (UTC) X-FDA: 84774510660.13.A19BE7E Received: from mail-yx1-f66.google.com (mail-yx1-f66.google.com [74.125.224.66]) by imf09.hostedemail.com (Postfix) with ESMTP id CAC73140011 for ; Sat, 16 May 2026 21:04:08 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=gwAFI2Rh; spf=pass (imf09.hostedemail.com: domain of ravis.opensrc@gmail.com designates 74.125.224.66 as permitted sender) smtp.mailfrom=ravis.opensrc@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778965448; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=3O47MXZLACGVXkwBLvK8wvdJrmJyHZnllVL8QQ770hw=; b=6JLBEmQ0Nl3E21vjzOjus+qC3nhUKvzUS+X1DljBTKdwqLEWzw4qLrvW16MbRLMukx9DmJ vE9DA4uh9q6G/gIW6n0PJU0+rDbuI+LnpJ3ACdGREYRTEVbb1dhKFJpZ3itU6jcdQqRpWo nG7F4xbdW23wI3nGDAiqmby7/zI2fc8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778965448; a=rsa-sha256; cv=none; b=NfZQad3wuonZhQwmY5QuEpTInJCiOipYDSys1Ei/u9o04280UzoFVCz9GW7vDn5nFxNDrx 4Bs97pOPJi1eMTYPyrps1CmOy4JSkWpg0Mcv/hZVfpkhfMSWLAfyDijy2FSR5oQfmZxthv EiO3bIMQpaBqSlK+RvG0JLvynxkEzfA= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=gwAFI2Rh; spf=pass (imf09.hostedemail.com: domain of ravis.opensrc@gmail.com designates 74.125.224.66 as permitted sender) smtp.mailfrom=ravis.opensrc@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-yx1-f66.google.com with SMTP id 956f58d0204a3-65c3ea2ebf7so1510242d50.0 for ; Sat, 16 May 2026 14:04:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778965448; x=1779570248; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=3O47MXZLACGVXkwBLvK8wvdJrmJyHZnllVL8QQ770hw=; b=gwAFI2Rh2MqIljiSS71ksh/cPkQ51NR6RCg//hsWWb6tTGMo5YCWFMnJvOM154dkr4 FJqUqK1VKIepiwCGQ+fjRt1tu1uP8sD3XVQz8OTQkxphfOtMwtgPXEWEitc+WRnwbnYy rV9ACtFFcQquNr/mJLlH/p9TJ1e5Ot2R+Cj56hGUeQvw57ET+7UgxcMfYpzXBukdtmcE jOXOoZkCTUDgInHhYgcAsHHOGj8nhHzOuEx3CcuBezeBwQH+0SFhg5jMQFYX4v2BoPd3 FqYZvPjjPYu/IbKv0pO1zKpZ2kxwnSRkMfq+o6oT74UxAFT44/O5FoROkM9RQmrq0wWp GZIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778965448; x=1779570248; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=3O47MXZLACGVXkwBLvK8wvdJrmJyHZnllVL8QQ770hw=; b=L7zdLdexlekxWVFKTnwjGMPm9m8xWPHDYBc1BPz1rMYNi4voCLSjCQ3p3wQR2NwtUc WZn1afCbWg1bmPn0wpfsDqZiuAGoAyB1voNTkjBc5LJB+3A+6H9W2jaajyeimisrAq8K rIf7sRF9h37/EXzcqOnoC1iZ5gde1Kw0HZdRiLXJKPHjuwPz/GVpXdnPOooXHdxkbzCK MXWCRK3mp9tRjlK+ro2LrlLLXb6BOSLPoXsqGpLprsMdcmE/WsXvPiNRul8dIdCJYCm9 96WUlhvQvwCaiAItpB+sN6paQcar7dIQMCnckLZWJBrFxhzgXnAuusbaYoXmvQvCzrhG 2Tsg== X-Forwarded-Encrypted: i=1; AFNElJ85l7Lcmcn+EXkC4PXnfeY/AmhtkASescibH2NtN8kBA0Yp21gBlCfy6NtUF1pna5bR9wKogfAy9Q==@kvack.org X-Gm-Message-State: AOJu0YxJbOySKzqygQUi/4hZ0tiN/GozX+W0rOCSgxajubyLyMvY1Xiz tO4EfTFiK+lMs1ecAl6PNHRId8S7NS0ATcah65MInyFpslaBHRZNUvo= X-Gm-Gg: Acq92OHQC8eiUrsKxm4az1WRGyeqULC9eW/0lwypOlL8VTDeYlJBLCGaFk2qoyMBy92 nyAXl91WxXewqH7aRcNDS6Xcvspndw0QEXvGS1FHlHzczE/2Qm83YRcARj3c+VNtttF0+FzAxBa mT66ycGrWOYfsRPTXoVYIrDdl9oBTsE64Gb9xPDxIiDdHxLPERF31nMyeYpYiUPkdWcITGk2I8S 5hQlXi9yFyCZuJXn7JHL1XuaZfc5b/LsSGXaSbEgBxrEgCN/zGCyFQzT6SCkazo1pvDb+OEuuOM dPjaYX0gzy8CMFjmt57qDEHn1tmQnlBcBxw9zMnhWT73jLfBpOQ7Tr0tgxvHLMR4ER/Y680rPWz OOJx3XqGeKXPWOGzMOtzpn5io5GQrzROAAlxJnM7nRsMiAnAo/2jhF08+6LkKf5Us0RR7IuKuMJ 50DG/g0G/5ZAB71iC0EPXdHxZKmJIDXUa7XPangEglz9pKeVTROgFVV9dGjptLCeroNDGWxet8L w== X-Received: by 2002:a05:690e:c43:b0:65c:1302:ee48 with SMTP id 956f58d0204a3-65e2286ae3cmr9596405d50.54.1778965447840; Sat, 16 May 2026 14:04:07 -0700 (PDT) Received: from localhost (23-116-43-216.lightspeed.sntcca.sbcglobal.net. [23.116.43.216]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-65e0d86bc02sm4342876d50.4.2026.05.16.14.04.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 May 2026 14:04:07 -0700 (PDT) From: Ravi Jonnalagadda To: sj@kernel.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, bijan311@gmail.com, ajayjoshi@micron.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, ravis.opensrc@gmail.com Subject: [RFC PATCH 3/5] mm/damon/core: floor effective quota size at minimum region size Date: Sat, 16 May 2026 14:03:55 -0700 Message-ID: <20260516210357.2247-4-ravis.opensrc@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260516210357.2247-1-ravis.opensrc@gmail.com> References: <20260516210357.2247-1-ravis.opensrc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: CAC73140011 X-Stat-Signature: ahs8axhpkxfxsk7o3h33a9hxycwoqbz5 X-Rspam-User: X-HE-Tag: 1778965448-524183 X-HE-Meta: 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 Fd72idoD 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The CONSIST quota goal tuner initializes esz_bp to 0, producing an effective quota size (esz) of 1 byte on the first tick. damos_quota_is_full() rejects all regions when esz < min_region_sz (default PAGE_SIZE = 4096), so no regions can be tried and no feedback reaches the tuner — a bootstrapping deadlock. Floor esz at ctx->min_region_sz after the tuner computes it, guarded by an esz != 0 check. The guard preserves the temporal tuner's intentional stop behavior: when score >= 10000 (goal met), temporal sets esz_bp = 0 to halt migration; the floor must not override that. Signed-off-by: Ravi Jonnalagadda --- mm/damon/core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index fd1db234ca304..d33c4360cbd60 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -2650,6 +2650,10 @@ static void damos_set_effective_quota(struct damon_ctx *ctx, struct damos *s) esz = quota->esz_bp / 10000; } + /* avoid cold-start deadlock, but respect tuner stop signal (esz=0) */ + if (esz) + esz = max_t(unsigned long, esz, ctx->min_region_sz); + if (quota->ms) { if (quota->total_charged_ns) throughput = mult_frac(quota->total_charged_sz, -- 2.43.0