From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 91DE03B6343; Tue, 31 Mar 2026 15:22:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774970539; cv=none; b=cnOgqZJBTfs5cF9b8dK+yIblQGz3y7/z4w7+R3eYrv8cRd9nIpuayvNfQ0Jtfz+Ci3h8ooRAQcVAUUT0ixpBuBZoAu2cl9fG4D89nowyOutMs3rv1fhdJV36c4O/oMrENxxdpShXlgL7ltVH67uVmGs7xqsnh/73S6GtetWQXlw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774970539; c=relaxed/simple; bh=76AReawEblF9zwLAiLT7vjcTU5NOi5gm84ErlbSFzuo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=oxgZrQoSV2A6s+P25K9UOknb2JSd5AKJbj6S+aZXOOR0Tq38JP9ay7Q9NvgOdIEt2fyeRQgdf+nB9ssa6Z90phNW7IYbS5ydiwkhzdMxL1dNSyuObnUGhShx1mV3XNRxf6KoOpQ2gmyU9tTIouX0lnYbZKgd3pWeiDDqgGBGBJ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=BhEkNpUP; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="BhEkNpUP" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 086C32364; Tue, 31 Mar 2026 08:22:11 -0700 (PDT) Received: from e142334-100.cambridge.arm.com (e142334-100.cambridge.arm.com [10.1.194.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 71EB73F641; Tue, 31 Mar 2026 08:22:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774970536; bh=76AReawEblF9zwLAiLT7vjcTU5NOi5gm84ErlbSFzuo=; h=From:To:Cc:Subject:Date:From; b=BhEkNpUP/+8uC6lI5Ab17iUM9+kpj5uey6UHxZP0PKUHKfHZtnCoHc6HYpk0mBube GIXymS/d4x/Nty4hMHA6KJ2e51fruiORAu5ewN+dUx0WKYIpYt3f91RxOn4bfZ97VO OIX4VkcwvPDNJqv6I8MdbYCDHtXck+Yjnlvqpa98= From: Muhammad Usama Anjum To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Uladzislau Rezki , Nick Terrell , David Sterba , Vishal Moola , linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Ryan.Roberts@arm.com, david.hildenbrand@arm.com Cc: Muhammad Usama Anjum Subject: [PATCH v5 0/3] mm: Free contiguous order-0 pages efficiently Date: Tue, 31 Mar 2026 16:21:58 +0100 Message-ID: <20260331152208.975266-1-usama.anjum@arm.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi All, A recent change to vmalloc caused some performance benchmark regressions (see [1]). I'm attempting to fix that (and at the same time significantly improve beyond the baseline) by freeing a contiguous set of order-0 pages as a batch. At the same time I observed that free_contig_range() was essentially doing the same thing as vfree() so I've fixed it there too. While at it, optimize the __free_contig_frozen_range() as well. Check that the contiguous range falls in the same section. If they aren't enabled, the if conditions get optimized out by the compiler as memdesc_section() returns 0. See num_pages_contiguous() for more details about it. [1] https://lore.kernel.org/all/66919a28-bc81-49c9-b68f-dd7c73395a0d@arm.com v6.18 - Before the patch causing regression was added mm-new - current latest code this series - v2 series of these patches (>0 is faster, <0 is slower, (R)/(I) = statistically significant Regression/Improvement) v6.18 vs mm-new +-----------------+----------------------------------------------------------+-------------------+-------------+ | Benchmark | Result Class | v6.18 (base) | mm-new | +=================+==========================================================+===================+=============+ | micromm/vmalloc | fix_align_alloc_test: p:1, h:0, l:500000 (usec) | 653643.33 | (R) -50.92% | | | fix_size_alloc_test: p:1, h:0, l:500000 (usec) | 366167.33 | (R) -11.96% | | | fix_size_alloc_test: p:4, h:0, l:500000 (usec) | 489484.00 | (R) -35.21% | | | fix_size_alloc_test: p:16, h:0, l:500000 (usec) | 1011250.33 | (R) -36.45% | | | fix_size_alloc_test: p:16, h:1, l:500000 (usec) | 1086812.33 | (R) -31.83% | | | fix_size_alloc_test: p:64, h:0, l:100000 (usec) | 657940.00 | (R) -38.62% | | | fix_size_alloc_test: p:64, h:1, l:100000 (usec) | 765422.00 | (R) -24.84% | | | fix_size_alloc_test: p:256, h:0, l:100000 (usec) | 2468585.00 | (R) -37.83% | | | fix_size_alloc_test: p:256, h:1, l:100000 (usec) | 2815758.33 | (R) -26.32% | | | fix_size_alloc_test: p:512, h:0, l:100000 (usec) | 4851969.00 | (R) -37.76% | | | fix_size_alloc_test: p:512, h:1, l:100000 (usec) | 4496257.33 | (R) -31.15% | | | full_fit_alloc_test: p:1, h:0, l:500000 (usec) | 570605.00 | -8.97% | | | kvfree_rcu_1_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 500866.00 | -5.88% | | | kvfree_rcu_2_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 499733.00 | -6.95% | | | long_busy_list_alloc_test: p:1, h:0, l:500000 (usec) | 5266237.67 | (R) -40.19% | | | pcpu_alloc_test: p:1, h:0, l:500000 (usec) | 490284.00 | -2.10% | | | random_size_align_alloc_test: p:1, h:0, l:500000 (usec) | 850986.33 | (R) -48.03% | | | random_size_alloc_test: p:1, h:0, l:500000 (usec) | 2712106.00 | (R) -40.48% | | | vm_map_ram_test: p:1, h:0, l:500000 (usec) | 111151.33 | 3.52% | +-----------------+----------------------------------------------------------+-------------------+-------------+ v6.18 vs mm-new with patches +-----------------+----------------------------------------------------------+-------------------+--------------+ | Benchmark | Result Class | v6.18 (base) | this series | +=================+==========================================================+===================+==============+ | micromm/vmalloc | fix_align_alloc_test: p:1, h:0, l:500000 (usec) | 653643.33 | -14.02% | | | fix_size_alloc_test: p:1, h:0, l:500000 (usec) | 366167.33 | -7.23% | | | fix_size_alloc_test: p:4, h:0, l:500000 (usec) | 489484.00 | -1.57% | | | fix_size_alloc_test: p:16, h:0, l:500000 (usec) | 1011250.33 | 1.57% | | | fix_size_alloc_test: p:16, h:1, l:500000 (usec) | 1086812.33 | (I) 15.75% | | | fix_size_alloc_test: p:64, h:0, l:100000 (usec) | 657940.00 | (I) 9.05% | | | fix_size_alloc_test: p:64, h:1, l:100000 (usec) | 765422.00 | (I) 38.45% | | | fix_size_alloc_test: p:256, h:0, l:100000 (usec) | 2468585.00 | (I) 12.56% | | | fix_size_alloc_test: p:256, h:1, l:100000 (usec) | 2815758.33 | (I) 38.61% | | | fix_size_alloc_test: p:512, h:0, l:100000 (usec) | 4851969.00 | (I) 13.43% | | | fix_size_alloc_test: p:512, h:1, l:100000 (usec) | 4496257.33 | (I) 49.21% | | | full_fit_alloc_test: p:1, h:0, l:500000 (usec) | 570605.00 | -8.47% | | | kvfree_rcu_1_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 500866.00 | -8.17% | | | kvfree_rcu_2_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 499733.00 | -5.54% | | | long_busy_list_alloc_test: p:1, h:0, l:500000 (usec) | 5266237.67 | (I) 4.63% | | | pcpu_alloc_test: p:1, h:0, l:500000 (usec) | 490284.00 | 1.53% | | | random_size_align_alloc_test: p:1, h:0, l:500000 (usec) | 850986.33 | -0.00% | | | random_size_alloc_test: p:1, h:0, l:500000 (usec) | 2712106.00 | 1.22% | | | vm_map_ram_test: p:1, h:0, l:500000 (usec) | 111151.33 | (I) 4.98% | +-----------------+----------------------------------------------------------+-------------------+--------------+ mm-new vs vmalloc_2 results are in 2/3 patch. So this series is mitigating the regression on average as results show -14% to 49% improvement. Thanks, Muhammad Usama Anjum --- Changes since v4: (summary) - Patch 1: move can_free initialization inside the loop - Patch 1: Use pfn_to_page() for each pfn instead of page++ - Patch 2: Use num_pages_contiguous() instead of raw loop Chagnes since v3: (summary) - Introduce __free_contig_range_common() in first patch and use it in 3rd patch as well - Cosmetic changes related to comments and kerneldoc Changes since v2: (summary) - Patch 1 and 3: Rework the loop to check for memory sections - Patch 2: Rework by removing the BUG on and add helper free_pages_bulk() Changes since v1: - Update description - Rebase on mm-new and rerun benchmarks/tests - Patch 1: move FPI_PREPARED check and add todo - Patch 2: Rework catering newer changes in vfree() - New Patch 3: optimizes __free_contig_frozen_range() Muhammad Usama Anjum (1): mm/page_alloc: Optimize __free_contig_frozen_range() Ryan Roberts (2): mm/page_alloc: Optimize free_contig_range() vmalloc: Optimize vfree include/linux/gfp.h | 4 ++ mm/page_alloc.c | 141 ++++++++++++++++++++++++++++++++++++++++++-- mm/vmalloc.c | 16 ++--- 3 files changed, 144 insertions(+), 17 deletions(-) -- 2.47.3