From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 013.lax.mailroute.net (013.lax.mailroute.net [199.89.1.16]) (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 83D9C36922D for ; Mon, 23 Mar 2026 20:29:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774297765; cv=none; b=USovXU3JsNzcX2uGWvHZqru0EK4kPVmimEvsz5Thavaw5CmxvMij+niDp524Q4h3xFiOWWEhcm+JmHWomoIUupyHtioRWIX3e4tR/NW3YazeDyZ/72cabi/eramdfabD7A1Gk6PNyS65xsQ6ep8vDE6bvdGGoIFr+3kAkOe7s0c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774297765; c=relaxed/simple; bh=d54RFIFd1VEIjF8sqlRKiB8kS1iA4lHKNbBXyR/CJmY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k9dZtfMjaoOnNHf+HRkNYz9RtPmoKCC5itW4lLXkRgpj+sEcYtExcex/FMEMqWu4fdfrWgNefSYRp11UgHqX6WepFzuEmfbTKsnBWdt9st3H/Rq9XC4dUOyxzirXRQndn4aYQxX18sWj/LSMJv+UrN3a0Qd+Pi97cFYokaBcpRc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=SkBsDfwj; arc=none smtp.client-ip=199.89.1.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="SkBsDfwj" Received: from localhost (localhost [127.0.0.1]) by 013.lax.mailroute.net (Postfix) with ESMTP id 4fflBp4xCrzlfgPq; Mon, 23 Mar 2026 20:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:mime-version:references:in-reply-to :x-mailer:message-id:date:date:subject:subject:from:from :received:received; s=mr01; t=1774297759; x=1776889760; bh=KhRKI oDWH9yqO5sYrwspWeVQ1ZooaBaPJyStEb2NTao=; b=SkBsDfwjaAhEv9ta0yWe9 YVfKgj1/nIlOdsCqjpRp5Xo7wEiDv6uY4T+7+yzQA1lpJHsu75ufXfK5R9UKKCtm 7Q5vXOGRvEHyJMlV6NgfxtACBJBIKLqYdlrIsjIyKNnariPmARfFKBDBdmCmONZZ ypQq7O1zhRA0NfMW0zIRL7aOGgKexwAEQo05ccLwfJlhK85XSGo6YkswTBQgo0Ry cHnIXOo3nlr6pMPVOtrDnupKgbt2ddn1guJNK3f0x00AQcINcP9UPxXdi6xsP/Rf vs4J7IiAWBotFSJXGfkhtItMO3/VvfCHn5Qt20jaHljACRUs39bGbJgUm2kqT+Cu Q== X-Virus-Scanned: by MailRoute Received: from 013.lax.mailroute.net ([127.0.0.1]) by localhost (013.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id rxi-uf1VlKxG; Mon, 23 Mar 2026 20:29:19 +0000 (UTC) Received: from bvanassche.mtv.corp.google.com (unknown [104.135.180.219]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 013.lax.mailroute.net (Postfix) with ESMTPSA id 4fflBk4NW5zlfl6N; Mon, 23 Mar 2026 20:29:18 +0000 (UTC) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Damien Le Moal , Bart Van Assche , Ming Lei Subject: [PATCH 1/2] block: Reduce BLK_MIN_SEGMENT_SIZE Date: Mon, 23 Mar 2026 13:29:01 -0700 Message-ID: <20260323202904.1248169-2-bvanassche@acm.org> X-Mailer: git-send-email 2.53.0.983.g0bb29b3bc5-goog In-Reply-To: <20260323202904.1248169-1-bvanassche@acm.org> References: <20260323202904.1248169-1-bvanassche@acm.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable The current value of BLK_MIN_SEGMENT_SIZE, 4096 bytes, makes it impossible to test small DMA segment size support on systems with a virtual memory page size of 4096 bytes. Hence reduce BLK_MIN_SEGMENT_SIZE to 512. There is nothing special about this value - any other value that is a divisor of 4096 and that doesn't cause lim->max_segments to be exceeded would also work. Cc: Ming Lei Cc: Christoph Hellwig Signed-off-by: Bart Van Assche --- block/blk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk.h b/block/blk.h index 7082dd5a87f9..7c792c012b0d 100644 --- a/block/blk.h +++ b/block/blk.h @@ -23,7 +23,7 @@ struct elv_change_ctx; #define BLK_DEF_MAX_SECTORS_CAP (SZ_4M >> SECTOR_SHIFT) =20 #define BLK_DEV_MAX_SECTORS (LLONG_MAX >> 9) -#define BLK_MIN_SEGMENT_SIZE 4096 +#define BLK_MIN_SEGMENT_SIZE 512 =20 /* Max future timer expiry for timeouts */ #define BLK_MAX_TIMEOUT (5 * HZ)