From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f52.google.com (mail-ej1-f52.google.com [209.85.218.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A70F4161936 for ; Tue, 9 Jul 2024 13:09:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720530547; cv=none; b=Ez9AKCaZGAKmOjYo/6x9dqDZ5/kpuigcLuJQot73taxEufz22BLKj9Z5/RyIiODjeW5MBSR1OCvwPxqsJFlrSWDeTIDSciJPW0E30Lgua0SIZOn/UGv9wwjQLt/wpTpwMBpjRQTzq8XxtPEr6JaUreBkz3qJEqvd1P9Spt5vD54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720530547; c=relaxed/simple; bh=MFDkzDl8sN/LKE4vYOsqFY2OpI9WfwI8lLUYaTz3VUM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=W6Jw440w9d0f0Agxq9Ilba3v/ySktcLgA1rv101A/coIGrdvzWo1iIrsM1mgoLf5+MC1mq4xbil9yHd4hlJWt561SLgx2uRlYHzWTF77TY0QdVi6DSxZ8nidCEQTQ6E75b8JJcnVeJyqIAzmJIuekBnudcP2YPisxzCEGGg75oY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Jo9+lG6P; arc=none smtp.client-ip=209.85.218.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Jo9+lG6P" Received: by mail-ej1-f52.google.com with SMTP id a640c23a62f3a-a77b550128dso641788166b.0 for ; Tue, 09 Jul 2024 06:09:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1720530544; x=1721135344; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=+bUULStyY3rdWe1Joe+BLAARKQOAymCPb0HGFy/OwWM=; b=Jo9+lG6PzEaI/qcSOV1Ar6Exy3xGhnRJVQoiMoJ1J8lg/0rbgpIV6IBlNOc+ZBSovA kLoEdJqvgmm1sBI7nQW2fKnUNN0r8AhcI1j4Cjk/jitLZc07C0Lz8tvlJrFxwyfgV04f 4AqzmejZjUCO5vUHwUaLz1s6DzwkqAhNpKE0s+NqJZUn9Qz2qH+ON/ZHGTmn/2ID3g98 /TtOipsn1tD++E4pfqkUZ2LyLSWo0HOLx5RGgH94Fm1jTkWbJnxxGPkYSc01qMWvJigE 0OCE8las+NSGYOLp9LjuCUt8Vb9kYU3EUaE46UD1Ay4HJcbNlf+tDsDnID/Qm4gpkyVO 4G3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720530544; x=1721135344; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+bUULStyY3rdWe1Joe+BLAARKQOAymCPb0HGFy/OwWM=; b=cnHdvpmiSnFeIXknUS1xiPZP5X4jcDxkp/jF4FoLY0KtkjS2QGw9iaVYHImHk+uyyH nV0l/US0+xkS+SmuOenGlKcaql6+rXTh6T9A5BvpbxVQjPE1PuRk+HzghamvnI9Di0yY 2AzyNzzAmS/NgtQ2bukR636kfwyKUHvtDvZv54aBsUEeW/S1qsT3zSbwRzbX/zsyFNyz sWCn4Nhx6clCp7iac4dgAC4VZBvg07y9jVk8qcgMk8kuIpkNosMDhKLrhc7IhiB4AlHh 3UOPQj88Z0IdmXWcs/qgOS/zlMU1aLKiMr0FGLalGgxewsmYTd/FqyJmGEXKwOis82Qe iNkg== X-Gm-Message-State: AOJu0YwAvFX2rDwlKX26031A0Zlm++bv9D6pkrbkmmuY69W8YJTHb/zM bA0L9POb3dn7Ck5aDrZND8xDxXMIIcMWsd4dpzyjMdwS/pr5FIOvNCOZXQ== X-Google-Smtp-Source: AGHT+IG83PtOV8EPKIibTADf8CcxsY/kn4FQNXCs8VM7oJIyvVMTseNaCoIPZgmImLuFjbLLiqDr9w== X-Received: by 2002:a17:906:6c93:b0:a72:6e13:a4b6 with SMTP id a640c23a62f3a-a780b88276bmr182336466b.58.1720530543642; Tue, 09 Jul 2024 06:09:03 -0700 (PDT) Received: from [192.168.42.197] ([163.114.131.193]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a780a7ff24esm76208766b.131.2024.07.09.06.09.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Jul 2024 06:09:03 -0700 (PDT) Message-ID: Date: Tue, 9 Jul 2024 14:09:12 +0100 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 1/3] io_uring/rsrc: add hugepage fixed buffer coalesce helpers To: Chenliang Li , axboe@kernel.dk Cc: io-uring@vger.kernel.org, peiwei.li@samsung.com, joshi.k@samsung.com, kundan.kumar@samsung.com, anuj20.g@samsung.com, gost.dev@samsung.com References: <20240628084411.2371-1-cliang01.li@samsung.com> <20240628084411.2371-2-cliang01.li@samsung.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20240628084411.2371-2-cliang01.li@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/28/24 09:44, Chenliang Li wrote: > Introduce helper functions to check and coalesce hugepage-backed fixed > buffers. The coalescing optimizes both time and space consumption caused > by mapping and storing multi-hugepage fixed buffers. Currently we only > have single-hugepage buffer coalescing, so add support for multi-hugepage > fixed buffer coalescing. > > A coalescable multi-hugepage buffer should fully cover its folios > (except potentially the first and last one), and these folios should > have the same size. These requirements are for easier processing later, > also we need same size'd chunks in io_import_fixed for fast iov_iter > adjust. > > Signed-off-by: Chenliang Li > --- > io_uring/rsrc.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++ > io_uring/rsrc.h | 9 +++++ > 2 files changed, 96 insertions(+) > > diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c > index 60c00144471a..c88ce8c38515 100644 > --- a/io_uring/rsrc.c > +++ b/io_uring/rsrc.c > @@ -849,6 +849,93 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, > return ret; > } > > +static bool io_do_coalesce_buffer(struct page ***pages, int *nr_pages, > + struct io_imu_folio_data *data, int nr_folios) > +{ > + struct page **page_array = *pages, **new_array = NULL; > + int nr_pages_left = *nr_pages, i, j; > + > + /* Store head pages only*/ > + new_array = kvmalloc_array(nr_folios, sizeof(struct page *), > + GFP_KERNEL); > + if (!new_array) > + return false; > + > + new_array[0] = page_array[0]; > + /* > + * The pages are bound to the folio, it doesn't > + * actually unpin them but drops all but one reference, > + * which is usually put down by io_buffer_unmap(). > + * Note, needs a better helper. > + */ > + if (data->nr_pages_head > 1) > + unpin_user_pages(&page_array[1], data->nr_pages_head - 1); > + > + j = data->nr_pages_head; > + nr_pages_left -= data->nr_pages_head; > + for (i = 1; i < nr_folios; i++) { > + unsigned int nr_unpin; > + > + new_array[i] = page_array[j]; > + nr_unpin = min_t(unsigned int, nr_pages_left - 1, > + data->nr_pages_mid - 1); > + if (nr_unpin) > + unpin_user_pages(&page_array[j+1], nr_unpin); > + j += data->nr_pages_mid; > + nr_pages_left -= data->nr_pages_mid; > + } > + kvfree(page_array); > + *pages = new_array; > + *nr_pages = nr_folios; > + return true; > +} > + > +static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages, > + struct io_imu_folio_data *data) I believe unused static function will trigger a warning, we don't want that, especially since error on warn is a thing. You can either reshuffle patches or at least add a __maybe_unused attribute. > +{ > + struct page **page_array = *pages; > + struct folio *folio = page_folio(page_array[0]); > + unsigned int count = 1, nr_folios = 1; > + int i; > + > + if (*nr_pages <= 1) > + return false; > + > + data->nr_pages_mid = folio_nr_pages(folio); > + if (data->nr_pages_mid == 1) > + return false; > + > + data->folio_shift = folio_shift(folio); > + data->folio_size = folio_size(folio); > + /* > + * Check if pages are contiguous inside a folio, and all folios have > + * the same page count except for the head and tail. > + */ > + for (i = 1; i < *nr_pages; i++) { > + if (page_folio(page_array[i]) == folio && > + page_array[i] == page_array[i-1] + 1) { > + count++; > + continue; > + } Seems like the first and last folios can be not border aligned, i.e. the first should end at the folio_size boundary, and the last one should start at the beginning of the folio. Not really a bug, but we might get some problems with optimising calculations down the road if we don't restrict it. > + > + if (nr_folios == 1) > + data->nr_pages_head = count; > + else if (count != data->nr_pages_mid) > + return false; > + > + folio = page_folio(page_array[i]); > + if (folio_size(folio) != data->folio_size) > + return false; > + > + count = 1; > + nr_folios++; > + } > + if (nr_folios == 1) > + data->nr_pages_head = count; > + > + return io_do_coalesce_buffer(pages, nr_pages, data, nr_folios); > +} > + > static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, > struct io_mapped_ubuf **pimu, > struct page **last_hpage) > diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h > index c032ca3436ca..cc66323535f6 100644 > --- a/io_uring/rsrc.h > +++ b/io_uring/rsrc.h > @@ -50,6 +50,15 @@ struct io_mapped_ubuf { > struct bio_vec bvec[] __counted_by(nr_bvecs); > }; > > +struct io_imu_folio_data { > + /* Head folio can be partially included in the fixed buf */ > + unsigned int nr_pages_head; > + /* For non-head/tail folios, has to be fully included */ > + unsigned int nr_pages_mid; > + unsigned int folio_shift; > + size_t folio_size; > +}; > + > void io_rsrc_node_ref_zero(struct io_rsrc_node *node); > void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *ref_node); > struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx); -- Pavel Begunkov