From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 BC0D92367DE for ; Mon, 14 Jul 2025 20:37:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752525470; cv=none; b=MD8rso/oxZQ+38rrEyZbXesJZr4iPEW2NI2/Y/knVS3vg0vZClEokA5ohJ9y6tkBWPdaMH0u3wL2vGuXjJy2HoRpqT9Vw+mVhTmJVWgg5c6ePExzV76d1T5/qFqmFZ1BR257lgqa6CjXp9ElmWXXbCXdKRUnJKqldRfvJ0yAnQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752525470; c=relaxed/simple; bh=o6lxpyRDhsKyt1kSzcpl+YFoFNmOOt4Bd/BQbj/e+Ro=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=WUc+oI0o6kMQYVg0gvySPwicLeKl5oyumpalaqDgg8M89i45c+soqC/J0uzqVarmqxS3ngJcTajhqVazjd00rNBiKV3FF71Ld4Xie+x2v0mutuJz/0/DmDx/9mrEvg22qesItEeVnunN5SrpODOtcrPNaw3+s9GWpkYhBmnSS6Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=OgoFwo2d; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OgoFwo2d" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752525467; h=from:from: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; bh=XLdZRvcQL8LOEfVl5rHLuZ7anpsrEIqyRbvnEXKnMtw=; b=OgoFwo2dET5XHlUauEp/nBZGQAOFsXG3QQtOXdEzC8orQI5mMpUiJnN0EP3DbM1onEjYCn N/+AL5haBc89ReCNxGr6IjIa6m6kEBZX0QpnGDX59xxSJC9BAqdxL+VnnpK8kSmFivYwMP YHzcnWsDnfyCBHIp+Lnl4kss7N10CnU= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-586-j6dcRWlsONyj34yYaO-DtA-1; Mon, 14 Jul 2025 16:37:45 -0400 X-MC-Unique: j6dcRWlsONyj34yYaO-DtA-1 X-Mimecast-MFC-AGG-ID: j6dcRWlsONyj34yYaO-DtA_1752525464 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4EDBD180120C; Mon, 14 Jul 2025 20:37:44 +0000 (UTC) Received: from bfoster.redhat.com (unknown [10.22.64.43]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 2333C19560A3; Mon, 14 Jul 2025 20:37:41 +0000 (UTC) From: Brian Foster To: linux-fsdevel@vger.kernel.org Cc: linux-xfs@vger.kernel.org, linux-mm@kvack.org, hch@infradead.org, djwong@kernel.org, willy@infradead.org Subject: [PATCH v3 1/7] filemap: add helper to look up dirty folios in a range Date: Mon, 14 Jul 2025 16:41:16 -0400 Message-ID: <20250714204122.349582-2-bfoster@redhat.com> In-Reply-To: <20250714204122.349582-1-bfoster@redhat.com> References: <20250714204122.349582-1-bfoster@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Add a new filemap_get_folios_dirty() helper to look up existing dirty folios in a range and add them to a folio_batch. This is to support optimization of certain iomap operations that only care about dirty folios in a target range. For example, zero range only zeroes the subset of dirty pages over unwritten mappings, seek hole/data may use similar logic in the future, etc. Note that the helper is intended for use under internal fs locks. Therefore it trylocks folios in order to filter out clean folios. This loosely follows the logic from filemap_range_has_writeback(). Signed-off-by: Brian Foster Reviewed-by: Christoph Hellwig --- include/linux/pagemap.h | 2 ++ mm/filemap.c | 58 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index e63fbfbd5b0f..fb83ddf26621 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -941,6 +941,8 @@ unsigned filemap_get_folios_contig(struct address_space *mapping, pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start, pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch); +unsigned filemap_get_folios_dirty(struct address_space *mapping, + pgoff_t *start, pgoff_t end, struct folio_batch *fbatch); /* * Returns locked page at given index in given cache, creating it if needed. diff --git a/mm/filemap.c b/mm/filemap.c index bada249b9fb7..2171b7f689b0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2334,6 +2334,64 @@ unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start, } EXPORT_SYMBOL(filemap_get_folios_tag); +/** + * filemap_get_folios_dirty - Get a batch of dirty folios + * @mapping: The address_space to search + * @start: The starting folio index + * @end: The final folio index (inclusive) + * @fbatch: The batch to fill + * + * filemap_get_folios_dirty() works exactly like filemap_get_folios(), except + * the returned folios are presumed to be dirty or undergoing writeback. Dirty + * state is presumed because we don't block on folio lock nor want to miss + * folios. Callers that need to can recheck state upon locking the folio. + * + * This may not return all dirty folios if the batch gets filled up. + * + * Return: The number of folios found. + * Also update @start to be positioned for traversal of the next folio. + */ +unsigned filemap_get_folios_dirty(struct address_space *mapping, pgoff_t *start, + pgoff_t end, struct folio_batch *fbatch) +{ + XA_STATE(xas, &mapping->i_pages, *start); + struct folio *folio; + + rcu_read_lock(); + while ((folio = find_get_entry(&xas, end, XA_PRESENT)) != NULL) { + if (xa_is_value(folio)) + continue; + if (folio_trylock(folio)) { + bool clean = !folio_test_dirty(folio) && + !folio_test_writeback(folio); + folio_unlock(folio); + if (clean) { + folio_put(folio); + continue; + } + } + if (!folio_batch_add(fbatch, folio)) { + unsigned long nr = folio_nr_pages(folio); + *start = folio->index + nr; + goto out; + } + } + /* + * We come here when there is no folio beyond @end. We take care to not + * overflow the index @start as it confuses some of the callers. This + * breaks the iteration when there is a folio at index -1 but that is + * already broke anyway. + */ + if (end == (pgoff_t)-1) + *start = (pgoff_t)-1; + else + *start = end + 1; +out: + rcu_read_unlock(); + + return folio_batch_count(fbatch); +} + /* * CD/DVDs are error prone. When a medium error occurs, the driver may fail * a _large_ part of the i/o request. Imagine the worst scenario: -- 2.50.0