From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C965048CD50 for ; Mon, 28 Sep 2026 08:50:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585457; cv=none; b=Lh4rdlutNeQLKdWd5r8z5dCr9Viqn+yjAkeK6BPWCBmhW2/rNKUz9q43llKczrYg8IZYmzW9Da6AvSPF+95qY3NK6Coib2m7JLXKlOFEgw5LgVS0xXeiRlcR/8hBm5kDIrx6YnCaTexVHisndZcjs9GrWr92h3tKQyhgZJ4D8U4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790585457; c=relaxed/simple; bh=8zF61l7XUYfPF/S5G0yQdjRwCBSBU/86WUkneKAj49I=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Fv5Gond8Pq7oXf8fKwDARzwgyf7AkODRHILQuIS2GejRGiq+vgzDTMfBb00bd10as6XG6iqPQNFKzyWycnK+OsMqFPbpWfJBlaUs4PtZCX/ENuEiz1mpXa6KK+3bltFq04n6PwKSPb7AtjapEa7wDleialOeCYA1qIuCdxRH4w8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KYUmyW+B; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KYUmyW+B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 643891F0089A; Mon, 28 Sep 2026 08:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790585456; bh=Y0HxyvWLDosZc5xoDwHVRTARrpEGTve+PHp4YKgftjg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=KYUmyW+BaiVQ9eaCXMlXub0b7FVy+20KbeJiMmA7wEis9lOT3u4QpXT+541Bv8gEg u8zE1qPjOi0++UXn3Sac7eSLLYW6p+KaJeFcp+bqaMEEhbIhCcZphFp9aM+AoWRAVD den/fg2Q/vOqMp96WD9aPDhVej++M7Rroz8vEWBPqL6XtmCpACY7Xn3BB15lB0Odbn QZ5z4+14GYj0vXsZAmflUG8lnHoJTENkoC/Tf3PoPNCqdi/kY/gIGLF+G72gGV4WKt zzvE45cNounrTKa9XN99krzVU1cA0Vg8vSOA9D+gaJ9SZKKJx0Acf/qDVr8MRpJsdy hXN1FTxJ0Sl/A== From: Linus Walleij Date: Mon, 28 Sep 2026 10:50:32 +0200 Subject: [PATCH net-next v2 06/11] net: ethernet: cortina: Rotate free queue page allocation Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260928-gemini-ethernet-fixes-3-v2-6-758a795d7a78@kernel.org> References: <20260928-gemini-ethernet-fixes-3-v2-0-758a795d7a78@kernel.org> In-Reply-To: <20260928-gemini-ethernet-fixes-3-v2-0-758a795d7a78@kernel.org> To: Hans Ulli Kroll , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , =?utf-8?q?Micha=C5=82_Miros=C5=82aw?= , Myeonghun Pak Cc: netdev@vger.kernel.org, Linus Walleij X-Mailer: b4 0.16.0 The free queue metadata bitmap currently searches for a free slot from zero for every page allocation. Under sustained traffic this repeatedly scans occupied low-numbered slots. Remember the position after the most recently allocated slot and wrap the bitmap search at its end. This keeps allocation cost distributed across the metadata table. Assisted-by: LLM Signed-off-by: Linus Walleij --- drivers/net/ethernet/cortina/gemini.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 8d216fa45287..385b78fd6653 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -172,6 +172,7 @@ struct gemini_ethernet { struct xarray freeq_mappings; unsigned int num_freeq_pages; unsigned long *freeq_page_bitmap; + unsigned int freeq_page_cursor; spinlock_t freeq_lock; /* Locks queue from reentrance */ }; @@ -743,12 +744,20 @@ static int geth_freeq_alloc_slot(struct gemini_ethernet *geth) lockdep_assert_held(&geth->freeq_lock); - slot = find_first_zero_bit(geth->freeq_page_bitmap, - geth->num_freeq_pages); - if (slot == geth->num_freeq_pages) - return -ENOSPC; + slot = find_next_zero_bit(geth->freeq_page_bitmap, + geth->num_freeq_pages, + geth->freeq_page_cursor); + if (slot == geth->num_freeq_pages) { + slot = find_first_zero_bit(geth->freeq_page_bitmap, + geth->freeq_page_cursor); + if (slot == geth->freeq_page_cursor) + return -ENOSPC; + } __set_bit(slot, geth->freeq_page_bitmap); + geth->freeq_page_cursor = slot + 1; + if (geth->freeq_page_cursor == geth->num_freeq_pages) + geth->freeq_page_cursor = 0; return slot; } @@ -1072,6 +1081,7 @@ static int geth_setup_freeq(struct gemini_ethernet *geth) if (!geth->freeq_page_bitmap) goto err_freeq_pages; geth->num_freeq_pages = page_slots; + geth->freeq_page_cursor = 0; expected = len - (1 << fpp_order); filled = geth_fill_freeq(geth); -- 2.55.0