From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9D992F49FD; Wed, 8 Jul 2026 14:11:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783519899; cv=none; b=s4wXqWXGzTfxIbOnHdaw37U4qTnXVqdl4saDnUp2+zCKnRP5CUxGtTXYzfkkTiTHFrtcbQ/HqlRCaqjFqa6FVZRCmfsrBtlNfLh0KwxbOIe/akd1bbH4uFU+L7LVxyqk3VyHYiO6GBeSHYlrm6wqin9zrtSwY+csDkwnQWHLt5Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783519899; c=relaxed/simple; bh=g+/R9e8kMmYBEjhykJ/JgMclt/rtf/u35Ssmi+dfqPw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MzIFMBihu1nHCKP+7MLZFtGRYZwkGDJ5RMHuqH672uQkqmRxB6ktYCn6zBsQTlit+7EN/EIogPrpL0cM3lAe1gtCMJgR2jtbij/GTNnSHJYzK9ZehJU+H2K5KtyBzxeUFnySJ5TBuVM9yHf/PidIftm5FB1mPX5qm5cizBbdGmQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lKK7qS3a; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lKK7qS3a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DF251F00A3D; Wed, 8 Jul 2026 14:11:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783519898; bh=oYNY6fayT8bgIf+rrVvdnnG8n7vDl1N8Udf7r3kCuck=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lKK7qS3ayOUoGqbDi/TxN4vTUQ3c46MmEmzbBUj7+5tgh6t0FPyeD7sJH8+N+7eN6 n4VRIjKu06gOYUah6DD63yV3pxz98udRx98r2J2kng87LWbCrR47I66j5SxjUDON1z /ifzB/LubUG0VxRxXXb6CxJ9N5VBoNo+xwWi5fjGMTBY6nz+Y/VCnmyHnQITS7R2YW aM72WF9/KZrqnZYjlRNnfJd+gUJmkNOeiZYvX1AAjz7q83GOOCaC2OX/cF28RGnqWS Ux9gp16W04ABGFXsAK6AGep466gRcm7OcBiQxxJ1dgSDMLpQ7LkwTVuWRJBrj2uuz4 +fExMa0KST6MA== From: SJ Park To: zjh Cc: SJ Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/damon: prevent migration fallback to non-target nodes Date: Wed, 8 Jul 2026 07:11:33 -0700 Message-ID: <20260708141134.123360-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hello jzh, On Wed, 8 Jul 2026 01:07:54 -0700 zjh wrote: > DAMOS_MIGRATE_{HOT,COLD} passes a target NUMA node to migrate_pages(). > But alloc_migration_target() treats mtc->nid as a preferred node unless > __GFP_THISNODE is set. Hence target allocation can fall back to another > node, and migrate_pages() can report success without placing the folio on > the requested target node. > > Make DAMON migration target allocation strict by setting __GFP_THISNODE. > This is consistent with alloc_misplaced_dst_folio() and > alloc_demote_folio(), which also use __GFP_THISNODE for migrations to an > explicit destination node. Thank you for sharing this patch. So this patch is introducing a small behavioral change. May I ask why you think the new behavior is better? Have you find some negative user impacts from the current behavior? > > Signed-off-by: zjh We as the kernel community disallow [1] anonymous patch submissions. Is zjh your preferred identity? Also, it is not a strict rule, but we as the mm community prefer using a formal name if that's ok. [1] https://docs.kernel.org/process/submitting-patches.html#developer-s-certificate-of-origin-1-1 Thanks, SJ [...]