From patchwork Mon Jul 24 18:54:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13325247 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E792C0015E for ; Mon, 24 Jul 2023 18:54:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229747AbjGXSyX (ORCPT ); Mon, 24 Jul 2023 14:54:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbjGXSyT (ORCPT ); Mon, 24 Jul 2023 14:54:19 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14059188 for ; Mon, 24 Jul 2023 11:54:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=v1353Pyv++o8NWvrrZQCLEMMSP1M9ywuP5OB+aDM0kw=; b=dTwfpe4CSf/wNXWMmkRXZpVHoZ vKf5kVMS43ZWZIFpaRKalQSU56M1zPmuvT0cTfRjsHG1ms+id4W5sGxNd+sE6EVlBjAaiNoNxDr1h Xonm4QEVzdVvQOSZTzKKLOlWi/7AHgQcxw+xBTzLLDTPshsCp14Xt1CAf3E711aCMTCmiUsbsyKRJ E7epN1PqMGdDThFGqBD/6NTEaQk9H9FaPMFkL5DFJJwMjPDD9zI0zKEXyQrh4HK4MTkWSaztP6OC+ hH67f752GSEuWd8RT90APXA9Co/fW4lHowfXBqJRfeXhMgCMSq4BVozxlTuI59Y7oVIbvi1uR9rCv csAytTjg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qO0hA-004iRF-Mf; Mon, 24 Jul 2023 18:54:12 +0000 From: "Matthew Wilcox (Oracle)" To: Andrew Morton Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Punit Agrawal , Suren Baghdasaryan Subject: [PATCH v3 08/10] mm: Run the fault-around code under the VMA lock Date: Mon, 24 Jul 2023 19:54:08 +0100 Message-Id: <20230724185410.1124082-9-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230724185410.1124082-1-willy@infradead.org> References: <20230724185410.1124082-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The map_pages fs method should be safe to run under the VMA lock instead of the mmap lock. This should have a measurable reduction in contention on the mmap lock. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Suren Baghdasaryan --- mm/memory.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 627a2abb969b..cf28afe7a416 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4661,11 +4661,6 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf) vm_fault_t ret = 0; struct folio *folio; - if (vmf->flags & FAULT_FLAG_VMA_LOCK) { - vma_end_read(vmf->vma); - return VM_FAULT_RETRY; - } - /* * Let's call ->map_pages() first and use ->fault() as fallback * if page by the offset is not ready to be mapped (cold cache or @@ -4677,6 +4672,11 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf) return ret; } + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + vma_end_read(vmf->vma); + return VM_FAULT_RETRY; + } + ret = __do_fault(vmf); if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) return ret;