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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD0F2C7EE29 for ; Thu, 8 Jun 2023 14:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234306AbjFHO0n (ORCPT ); Thu, 8 Jun 2023 10:26:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236781AbjFHO0i (ORCPT ); Thu, 8 Jun 2023 10:26:38 -0400 Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEBED2D68 for ; Thu, 8 Jun 2023 07:26:15 -0700 (PDT) Received: by mail-pf1-x42f.google.com with SMTP id d2e1a72fcca58-65292f79456so394507b3a.2 for ; Thu, 08 Jun 2023 07:26:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686234361; x=1688826361; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=OnoedkoiLsL0tLJYDXF1NYn5Qb4R2gxxmXGm3HjM2kw=; b=H7UvU4+Cu5Ls9GovjGu5sw+DLDlo+SEQ7Pj9pFQUXI+arPhcc/rG6cgn/N04MyMs4g rNQDDrHeQEAEQhh46HR8VhzW5Rhnff1RzC+72uF/cLXyudXFzJb9cftciLyMcKrEdh0E 8SAUuyNHD7Jy/w/ZaSbSTczyJaut2ZvBHXUYyfNC75FKC5QUUBNZN14Gd3XVPiZJRq2A Jwi4iH766Mw4gDvXULcD2y+YEX28oVJ6pr9BmgruKyukSHrrYnC8Hm6EXnqX/Fz/D+iW WnNEEb+LCoRqSwTryWnImZe7fp8L7hUSqa0zOH2FBTCM7VItFk4oGlf78WRkHG150ztx pxVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686234361; x=1688826361; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OnoedkoiLsL0tLJYDXF1NYn5Qb4R2gxxmXGm3HjM2kw=; b=ZWnIO8JJ2/cDbNdUNFlF+Jau9hCUEKy+pJglVYT4si33XH6ZAx5xH1jI7Fy+3uDEXw AfLZEwcWk9U5KsIjiL67uqc9YoCOuhHLjgSQ9bCpllagHsI4YXDwHv7nH99AqDwJRAkE zN+FDN8dhpRbLmWYyCQMldkvu9Kt9FTLJUlJR0bWt5b1SHEfVUAg1yuv14iPxwsbbq8o DSQOUqG7tUB7Jj/zlC17ASzx1RMuUwRQoNeK5jHlvFw45YDyxre0AX2sfM8RFECqaLY6 8zqU0xbQKcQERAA/lDNwjm07Dm8OW2C4eIwzP3a0+v3jyxEHhg7m+FTM2ZNFF20T3fch EFng== X-Gm-Message-State: AC+VfDyIGOHpI1s/s/P3rOhD5LxWljp07NwFRzlj11KQGMbRhsvoH81n wmfz2vzq2ZtglHZgHsFS/VU= X-Google-Smtp-Source: ACHHUZ6MOG1Hd2uceavhD8Eb8zbsWGFQuQO+S1FpmJYxHNmRX/oBQu53oSWEWJIECUiRyik1J3RvCQ== X-Received: by 2002:a17:902:da8c:b0:1b0:5ca0:41a8 with SMTP id j12-20020a170902da8c00b001b05ca041a8mr5134985plx.39.1686234360542; Thu, 08 Jun 2023 07:26:00 -0700 (PDT) Received: from sumitra.com ([117.255.153.95]) by smtp.gmail.com with ESMTPSA id x21-20020a17090300d500b001a221d14179sm1483052plc.302.2023.06.08.07.25.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jun 2023 07:26:00 -0700 (PDT) Date: Thu, 8 Jun 2023 07:25:53 -0700 From: Sumitra Sharma To: =?iso-8859-1?B?Suly9G1l?= Glisse , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Deepak R Varma , "Fabio M. De Francesco" , Ira Weiny Subject: [PATCH] staging: lib: Use memcpy_to/from_page() Message-ID: <20230608142553.GA341787@sumitra.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Deprecate kmap() in favor of kmap_local_page() due to high cost, restricted mapping space, the overhead of a global lock for synchronization, and making the process sleep in the absence of free slots. kmap_local_page() offers thread-local and CPU-local mappings, take pagefaults in a local kmap region and preserves preemption by saving the mappings of outgoing task and restoring those of the incoming one during a context switch. It is faster than kmap(), and in functions "dmirror_do_read" and "dmirror_do_write" the mappings are kept local to the thread. Therefore, replace kmap/mem*()/kunmap pattern with memcpy_to/from_page() and remove the unused variable "tmp". Signed-off-by: Sumitra Sharma --- Suggested-by: Fabio M. De Francesco lib/test_hmm.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 67e6f83fe0f8..cc96dfa54122 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -368,16 +368,13 @@ static int dmirror_do_read(struct dmirror *dmirror, unsigned long start, for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { void *entry; struct page *page; - void *tmp; entry = xa_load(&dmirror->pt, pfn); page = xa_untag_pointer(entry); if (!page) return -ENOENT; - tmp = kmap(page); - memcpy(ptr, tmp, PAGE_SIZE); - kunmap(page); + memcpy_from_page((char *)ptr, page, 0, PAGE_SIZE); ptr += PAGE_SIZE; bounce->cpages++; @@ -437,16 +434,13 @@ static int dmirror_do_write(struct dmirror *dmirror, unsigned long start, for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { void *entry; struct page *page; - void *tmp; entry = xa_load(&dmirror->pt, pfn); page = xa_untag_pointer(entry); if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE) return -ENOENT; - tmp = kmap(page); - memcpy(tmp, ptr, PAGE_SIZE); - kunmap(page); + memcpy_to_page(page, 0, (char *)ptr, PAGE_SIZE); ptr += PAGE_SIZE; bounce->cpages++; -- 2.25.1