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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BDF59C433EF for ; Wed, 3 Nov 2021 14:52:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2A9161076 for ; Wed, 3 Nov 2021 14:52:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230500AbhKCOzI (ORCPT ); Wed, 3 Nov 2021 10:55:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56589 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230132AbhKCOzI (ORCPT ); Wed, 3 Nov 2021 10:55:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635951151; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kTzGd0AKmjFHRo7fXFpfjY5blmceuKFi00MsYOAPKc0=; b=GgQtuX520aqol8ve0QVlaQR9WizOO/cUMrkZt9hnFdLcp0P1nknDCCwM/ufKfuE6QNdu1n lIkTU9ZPPEikjdDjmfoS+STObjqXCpuGrxFm90WGrWQzV29T+n0jMWarV/Ik4Fm74RJbeu 1cjVz0Gh8tU5UKMSgukc7sF1m7YNaPo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-462-s3WqVMe_Opi-PaffJS9v5Q-1; Wed, 03 Nov 2021 10:52:27 -0400 X-MC-Unique: s3WqVMe_Opi-PaffJS9v5Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 75624A40E1; Wed, 3 Nov 2021 14:51:29 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.194.74]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2298C19741; Wed, 3 Nov 2021 14:51:27 +0000 (UTC) From: Lukas Czerner To: linux-ext4@vger.kernel.org, tytso@mit.edu Cc: adilger@dilger.ca, Laurent GUERBY Subject: [PATCH v3 2/2] ext4: Allow to change s_last_trim_minblks via sysfs Date: Wed, 3 Nov 2021 15:51:22 +0100 Message-Id: <20211103145122.17338-2-lczerner@redhat.com> In-Reply-To: <20211103145122.17338-1-lczerner@redhat.com> References: <20211103145122.17338-1-lczerner@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Ext4 has an optimization mechanism for batched disacrd (FITRIM) that should help speed up subsequent calls of FITRIM ioctl by skipping the groups that were previously trimmed. However because the FITRIM allows to set the minimum size of an extent to trim, ext4 stores the last minimum extent size and only avoids trimming the group if it was previously trimmed with minimum extent size equal to, or smaller than the current call. There is currently no way to bypass the optimization without umount/mount cycle. This becomes a problem when the file system is live migrated to a different storage, because the optimization will prevent possibly useful discard calls to the storage. Fix it by exporting the s_last_trim_minblks via sysfs interface which will allow us to set the minimum size to the number of blocks larger than subsequent FITRIM call, effectively bypassing the optimization. By setting the s_last_trim_minblks to ULONG_MAX the optimization will be effectively cleared regardless of the previous state, or file system configuration. For example: getconf ULONG_MAX > /sys/fs/ext4/dm-1/last_trim_minblks Signed-off-by: Lukas Czerner Reported-by: Laurent GUERBY --- v2: Remove unnecessary assignment v3: s_last_trim_minblks is now unsinged long which simplifies this fs/ext4/sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index 2314f7446592..95d8a996d2d8 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -245,6 +245,7 @@ EXT4_ATTR(last_error_time, 0444, last_error_time); EXT4_ATTR(journal_task, 0444, journal_task); EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch); EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit); +EXT4_RW_ATTR_SBI_UL(last_trim_minblks, s_last_trim_minblks); static unsigned int old_bump_val = 128; EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val); @@ -295,6 +296,7 @@ static struct attribute *ext4_attrs[] = { #endif ATTR_LIST(mb_prefetch), ATTR_LIST(mb_prefetch_limit), + ATTR_LIST(last_trim_minblks), NULL, }; ATTRIBUTE_GROUPS(ext4); -- 2.31.1