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 X-Spam-Level: X-Spam-Status: No, score=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FDC8C4332F for ; Mon, 20 Sep 2021 07:23:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55D4F60FF2 for ; Mon, 20 Sep 2021 07:23:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234927AbhITHYn (ORCPT ); Mon, 20 Sep 2021 03:24:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234934AbhITHYm (ORCPT ); Mon, 20 Sep 2021 03:24:42 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 134FFC061762 for ; Mon, 20 Sep 2021 00:23:16 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id g19-20020a1c9d13000000b003075062d4daso11371151wme.0 for ; Mon, 20 Sep 2021 00:23:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=0M+kSw4lGcuEpkngLdEE2aUmmhCoCvNuYWVNUrrpaN8=; b=Y+tYcuGrVLiqvrZMolyepjQd20o6WKAck4ITrk2efyspM1rbEMBgH5InWQwkOhxrV9 FGpUFJ492K0i4fsYk500qKzG/ru7qw6nBUe4vcOVY2j6lCR3nSdmu/VkoJu2hBvpTCz6 JhFRv/k4lUqHUWUUzMVC9gGAoO2dJkXj9xNhMUXD9qcTxNg8zcZnwc4xreH4SNo/ziff /n0HRLUnY32+5LB3K1laH+iPzuLa44u0cB3Ig0XTMVbPdX43ccWOMges6Vg09G0sGNJG ErFzb/zIYd39lVTFRGcPRYDeZnRrPsdejCrgfbF2HMOM71+HH0T5nPzEkf4gRHCigszu sj6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=0M+kSw4lGcuEpkngLdEE2aUmmhCoCvNuYWVNUrrpaN8=; b=COVq2TW/IDSBYP5sZ+9BXbKb9zwiOJOhsHuLvEgu9iQLC4NjtTvWLd6FEe99ij8JTp RMxteBpIfDDoPIvtULQOAoHnhngly7UEib3NcOth90+inpvGlVBpGp14DVQagR+mnJvm Q5LAIAM/Tg98ZQv9IR/i3ysJyQUEZTenY0p/M/YeqhvCx7HhVgPNCU4Zpm2dhEZ4Oapv FMpoh1yFCL2WBoUOjgtm1/xSyTOvyKATPKqorf5oULxarzDQ0EC6t1nPUUeYPzeJz0FU KS0/Yg5s4ZNNYdEMjYfqj6oT9VPaJ1P/0aC3A7VsZuPG++4QR48lS6Rv9sMncwuwikCM pOpw== X-Gm-Message-State: AOAM533BeXVzFRLtn8MyspeFEtfTqNcxkAjxv4KZDEGZey6+fTApsTh4 y5Cd6PNSknOL/gRnyHWn6h0= X-Google-Smtp-Source: ABdhPJwZtfUC9F+9WQXGaFkX9XQ2onZ9sbJUuGe3PpumfGeONn0tOhWXjuYUb0VVgAXXufQyWYhQmw== X-Received: by 2002:a05:600c:2109:: with SMTP id u9mr7813185wml.6.1632122594458; Mon, 20 Sep 2021 00:23:14 -0700 (PDT) Received: from [192.168.178.21] (p5b0ea1b5.dip0.t-ipconnect.de. [91.14.161.181]) by smtp.gmail.com with ESMTPSA id 135sm10197632wma.32.2021.09.20.00.23.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Sep 2021 00:23:14 -0700 (PDT) Subject: Re: [PATCH 03/26] dma-buf: use new iterator in dma_resv_copy_fences To: Daniel Vetter Cc: linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org References: <20210917123513.1106-1-christian.koenig@amd.com> <20210917123513.1106-4-christian.koenig@amd.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <49eb0395-5446-62b8-da06-9c4c23eda843@gmail.com> Date: Mon, 20 Sep 2021 09:23:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Am 17.09.21 um 16:35 schrieb Daniel Vetter: > On Fri, Sep 17, 2021 at 02:34:50PM +0200, Christian König wrote: >> This makes the function much simpler since the complex >> retry logic is now handled else where. >> >> Signed-off-by: Christian König >> --- >> drivers/dma-buf/dma-resv.c | 86 ++++++++++++++++---------------------- >> 1 file changed, 35 insertions(+), 51 deletions(-) >> >> diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c >> index a3c79a99fb44..406150dea5e4 100644 >> --- a/drivers/dma-buf/dma-resv.c >> +++ b/drivers/dma-buf/dma-resv.c >> @@ -426,74 +426,58 @@ EXPORT_SYMBOL_GPL(dma_resv_iter_walk); >> */ >> int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src) >> { >> - struct dma_resv_list *src_list, *dst_list; >> - struct dma_fence *old, *new; >> - unsigned int i; >> + struct dma_resv_iter cursor; >> + struct dma_resv_list *list; >> + struct dma_fence *f, *excl; >> >> dma_resv_assert_held(dst); >> >> - rcu_read_lock(); >> - src_list = dma_resv_shared_list(src); >> - >> -retry: >> - if (src_list) { >> - unsigned int shared_count = src_list->shared_count; >> - >> - rcu_read_unlock(); >> + list = NULL; >> + excl = NULL; >> >> - dst_list = dma_resv_list_alloc(shared_count); >> - if (!dst_list) >> - return -ENOMEM; >> + rcu_read_lock(); >> + dma_resv_iter_begin(&cursor, src, true); >> + dma_resv_for_each_fence_unlocked(&cursor, f) { >> >> - rcu_read_lock(); >> - src_list = dma_resv_shared_list(src); >> - if (!src_list || src_list->shared_count > shared_count) { >> - kfree(dst_list); >> - goto retry; >> - } >> + if (cursor.is_first) { > Maybe have a wrapper for this, like dma_resv_iter_is_reset or is_first or > is_restart (my preference) with some nice docs that this returns true > everytime we had to restart the sequence? Exactly that's what I wanted to avoid since the is_first (or whatever) function should only be used inside of the dma_resv.c code. On the other hand I can just make that static here and document that it should never be exported. Christian. > > Otherwise I fully agree, this is so much better with all the hairy > restarting and get_rcu and test_bit shovelled away somewhere. > > Either way (but I much prefer a wrapper for is_first): > > Reviewed-by: Daniel Vetter > >> + dma_resv_list_free(list); >> + dma_fence_put(excl); >> >> - dst_list->shared_count = 0; >> - for (i = 0; i < src_list->shared_count; ++i) { >> - struct dma_fence __rcu **dst; >> - struct dma_fence *fence; >> + if (cursor.fences) { >> + unsigned int cnt = cursor.fences->shared_count; >> >> - fence = rcu_dereference(src_list->shared[i]); >> - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, >> - &fence->flags)) >> - continue; >> + rcu_read_unlock(); >> + list = dma_resv_list_alloc(cnt); >> + if (!list) { >> + dma_resv_iter_end(&cursor); >> + return -ENOMEM; >> + } >> >> - if (!dma_fence_get_rcu(fence)) { >> - dma_resv_list_free(dst_list); >> - src_list = dma_resv_shared_list(src); >> - goto retry; >> - } >> + list->shared_count = 0; >> + rcu_read_lock(); >> >> - if (dma_fence_is_signaled(fence)) { >> - dma_fence_put(fence); >> - continue; >> + } else { >> + list = NULL; >> } >> - >> - dst = &dst_list->shared[dst_list->shared_count++]; >> - rcu_assign_pointer(*dst, fence); >> + excl = NULL; >> } >> - } else { >> - dst_list = NULL; >> - } >> >> - new = dma_fence_get_rcu_safe(&src->fence_excl); >> + dma_fence_get(f); >> + if (dma_resv_iter_is_exclusive(&cursor)) >> + excl = f; >> + else >> + RCU_INIT_POINTER(list->shared[list->shared_count++], f); >> + } >> + dma_resv_iter_end(&cursor); >> rcu_read_unlock(); >> >> - src_list = dma_resv_shared_list(dst); >> - old = dma_resv_excl_fence(dst); >> - >> write_seqcount_begin(&dst->seq); >> - /* write_seqcount_begin provides the necessary memory barrier */ >> - RCU_INIT_POINTER(dst->fence_excl, new); >> - RCU_INIT_POINTER(dst->fence, dst_list); >> + excl = rcu_replace_pointer(dst->fence_excl, excl, dma_resv_held(dst)); >> + list = rcu_replace_pointer(dst->fence, list, dma_resv_held(dst)); >> write_seqcount_end(&dst->seq); >> >> - dma_resv_list_free(src_list); >> - dma_fence_put(old); >> + dma_resv_list_free(list); >> + dma_fence_put(excl); >> >> return 0; >> } >> -- >> 2.25.1 >> 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 X-Spam-Level: X-Spam-Status: No, score=-12.0 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B844C433F5 for ; Mon, 20 Sep 2021 13:28:42 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E03816109E for ; 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[91.14.161.181]) by smtp.gmail.com with ESMTPSA id 135sm10197632wma.32.2021.09.20.00.23.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Sep 2021 00:23:14 -0700 (PDT) To: Daniel Vetter Cc: linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org References: <20210917123513.1106-1-christian.koenig@amd.com> <20210917123513.1106-4-christian.koenig@amd.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <49eb0395-5446-62b8-da06-9c4c23eda843@gmail.com> Date: Mon, 20 Sep 2021 09:23:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Mailman-Approved-At: Mon, 20 Sep 2021 13:28:35 +0000 Subject: Re: [Intel-gfx] [PATCH 03/26] dma-buf: use new iterator in dma_resv_copy_fences X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Am 17.09.21 um 16:35 schrieb Daniel Vetter: > On Fri, Sep 17, 2021 at 02:34:50PM +0200, Christian König wrote: >> This makes the function much simpler since the complex >> retry logic is now handled else where. >> >> Signed-off-by: Christian König >> --- >> drivers/dma-buf/dma-resv.c | 86 ++++++++++++++++---------------------- >> 1 file changed, 35 insertions(+), 51 deletions(-) >> >> diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c >> index a3c79a99fb44..406150dea5e4 100644 >> --- a/drivers/dma-buf/dma-resv.c >> +++ b/drivers/dma-buf/dma-resv.c >> @@ -426,74 +426,58 @@ EXPORT_SYMBOL_GPL(dma_resv_iter_walk); >> */ >> int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src) >> { >> - struct dma_resv_list *src_list, *dst_list; >> - struct dma_fence *old, *new; >> - unsigned int i; >> + struct dma_resv_iter cursor; >> + struct dma_resv_list *list; >> + struct dma_fence *f, *excl; >> >> dma_resv_assert_held(dst); >> >> - rcu_read_lock(); >> - src_list = dma_resv_shared_list(src); >> - >> -retry: >> - if (src_list) { >> - unsigned int shared_count = src_list->shared_count; >> - >> - rcu_read_unlock(); >> + list = NULL; >> + excl = NULL; >> >> - dst_list = dma_resv_list_alloc(shared_count); >> - if (!dst_list) >> - return -ENOMEM; >> + rcu_read_lock(); >> + dma_resv_iter_begin(&cursor, src, true); >> + dma_resv_for_each_fence_unlocked(&cursor, f) { >> >> - rcu_read_lock(); >> - src_list = dma_resv_shared_list(src); >> - if (!src_list || src_list->shared_count > shared_count) { >> - kfree(dst_list); >> - goto retry; >> - } >> + if (cursor.is_first) { > Maybe have a wrapper for this, like dma_resv_iter_is_reset or is_first or > is_restart (my preference) with some nice docs that this returns true > everytime we had to restart the sequence? Exactly that's what I wanted to avoid since the is_first (or whatever) function should only be used inside of the dma_resv.c code. On the other hand I can just make that static here and document that it should never be exported. Christian. > > Otherwise I fully agree, this is so much better with all the hairy > restarting and get_rcu and test_bit shovelled away somewhere. > > Either way (but I much prefer a wrapper for is_first): > > Reviewed-by: Daniel Vetter > >> + dma_resv_list_free(list); >> + dma_fence_put(excl); >> >> - dst_list->shared_count = 0; >> - for (i = 0; i < src_list->shared_count; ++i) { >> - struct dma_fence __rcu **dst; >> - struct dma_fence *fence; >> + if (cursor.fences) { >> + unsigned int cnt = cursor.fences->shared_count; >> >> - fence = rcu_dereference(src_list->shared[i]); >> - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, >> - &fence->flags)) >> - continue; >> + rcu_read_unlock(); >> + list = dma_resv_list_alloc(cnt); >> + if (!list) { >> + dma_resv_iter_end(&cursor); >> + return -ENOMEM; >> + } >> >> - if (!dma_fence_get_rcu(fence)) { >> - dma_resv_list_free(dst_list); >> - src_list = dma_resv_shared_list(src); >> - goto retry; >> - } >> + list->shared_count = 0; >> + rcu_read_lock(); >> >> - if (dma_fence_is_signaled(fence)) { >> - dma_fence_put(fence); >> - continue; >> + } else { >> + list = NULL; >> } >> - >> - dst = &dst_list->shared[dst_list->shared_count++]; >> - rcu_assign_pointer(*dst, fence); >> + excl = NULL; >> } >> - } else { >> - dst_list = NULL; >> - } >> >> - new = dma_fence_get_rcu_safe(&src->fence_excl); >> + dma_fence_get(f); >> + if (dma_resv_iter_is_exclusive(&cursor)) >> + excl = f; >> + else >> + RCU_INIT_POINTER(list->shared[list->shared_count++], f); >> + } >> + dma_resv_iter_end(&cursor); >> rcu_read_unlock(); >> >> - src_list = dma_resv_shared_list(dst); >> - old = dma_resv_excl_fence(dst); >> - >> write_seqcount_begin(&dst->seq); >> - /* write_seqcount_begin provides the necessary memory barrier */ >> - RCU_INIT_POINTER(dst->fence_excl, new); >> - RCU_INIT_POINTER(dst->fence, dst_list); >> + excl = rcu_replace_pointer(dst->fence_excl, excl, dma_resv_held(dst)); >> + list = rcu_replace_pointer(dst->fence, list, dma_resv_held(dst)); >> write_seqcount_end(&dst->seq); >> >> - dma_resv_list_free(src_list); >> - dma_fence_put(old); >> + dma_resv_list_free(list); >> + dma_fence_put(excl); >> >> return 0; >> } >> -- >> 2.25.1 >>