From nobody Sat Feb 7 17:48:55 2026 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 5A0F17CF1D for ; Fri, 23 Feb 2024 13:01:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708693270; cv=none; b=sJcQgeS+1b3UuShEiiNMy0ytJU6wwDQqSxI2rrIb7xX4KHohjqlCj57sX9KIht9YGSuzNerkttUs09ueXxu38+KOlZ6Fx4gqPo34OKzIuPVqgBN/mrD/PPVbkJBhMbaF2UVyWvMOwACfn0YjU/iXLpkPTlUSeA6Y9Acr5zk9uls= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708693270; c=relaxed/simple; bh=8zCjAhelcZ3RRKa7WFuIXi9YgEQhHdl4OA8stTHmYYE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FObKgosaCr+gYtQxsGxSqjzNGAVc31rrTivWUQsenrEU8NolbuDdy4b5ZHkL1glZt1hJNEp6VLlcJaaKRwUjTUTOZ+YqyZwAi84ard3VrjVFc+7W4AsLaZ1DwbQfBbnew9p/EpT5v2cNSl+Vlqi1czV1tKCtarFmdiRKzlyZtq4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Hbzqe4kj; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Hbzqe4kj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708693269; x=1740229269; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=8zCjAhelcZ3RRKa7WFuIXi9YgEQhHdl4OA8stTHmYYE=; b=Hbzqe4kj/jTcTeIdv7Q3Y2HAGHTGZdCJTRg/nVhjn33xhwZ6pVGSi0k1 9LcRLb64ae3xn+MXyhpUkgwX8x4l1sNbavLWKLhc3co5iA8auwNzmczKJ OWKHFG0LAea41lX1lJe3Eo646HNHr5sJDWiHFFzfYUu4YN+EZ6tzdO/hm CqgV0H3D3a2a3a7axcN1A9jCloSd2mkX30lXojSu/pUUnDIN2IfFTuPq0 zcEakfcyxVjRLe+HvwKQAztrOfkZPzpAsqklWdQhwHqBYywqA+yDy1b2k /C+PrK1UJMsEmhs2m4mtvw/TQvE3dzOPhpE/wSMHGLufARIwTEjvgxjhL w==; X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="25479602" X-IronPort-AV: E=Sophos;i="6.06,180,1705392000"; d="scan'208";a="25479602" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Feb 2024 05:01:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,180,1705392000"; d="scan'208";a="10596216" Received: from linux-pnp-server-09.sh.intel.com ([10.239.176.190]) by orviesa004.jf.intel.com with ESMTP; 23 Feb 2024 05:01:04 -0800 From: rulinhuang To: urezki@gmail.com, bhe@redhat.com Cc: colin.king@intel.com, hch@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lstoakes@gmail.com, rulin.huang@intel.com, tianyou.li@intel.com, tim.c.chen@intel.com, wangyang.guo@intel.com, zhiguo.zhou@intel.com Subject: [PATCH v5] mm/vmalloc: lock contention optimization under multi-threading Date: Fri, 23 Feb 2024 08:03:19 -0500 Message-ID: <20240223130318.112198-2-rulin.huang@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240207033059.1565623-1-rulin.huang@intel.com> References: <20240207033059.1565623-1-rulin.huang@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When allocating a new memory area where the mapping address range is known, it is observed that the vmap_area lock is acquired twice. The first acquisition occurs in the alloc_vmap_area() function when inserting the vm area into the vm mapping red-black tree. The second acquisition occurs in the setup_vmalloc_vm() function when updating the properties of the vm, such as flags and address, etc. Combine these two operations together in alloc_vmap_area(), which improves scalability when the vmap_area lock is contended. By doing so, the need to acquire the lock twice can also be eliminated. With the above change, tested on intel icelake platform(160 vcpu, kernel v6.7), a 6% performance improvement and a 7% reduction in overall spinlock hotspot are gained on stress-ng/pthread(https://github.com/ColinIanKing/stress-ng), which is the stress test of thread creations. Reviewed-by: Chen Tim C Reviewed-by: King Colin Signed-off-by: rulinhuang --- V1 -> V2: Avoided the partial initialization issue of vm and separated insert_vmap_area() from alloc_vmap_area() V2 -> V3: Rebased on 6.8-rc5 V3 -> V4: Rebased on mm-unstable branch V4 -> V5: cancel the split of alloc_vmap_area() and keep insert_vmap_area() --- mm/vmalloc.c | 48 ++++++++++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 26 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 25a8df497255..6baaf08737f8 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1841,15 +1841,26 @@ node_alloc(unsigned long size, unsigned long align, return va; } =20 +static inline void setup_vmalloc_vm(struct vm_struct *vm, + struct vmap_area *va, unsigned long flags, const void *caller) +{ + vm->flags =3D flags; + vm->addr =3D (void *)va->va_start; + vm->size =3D va->va_end - va->va_start; + vm->caller =3D caller; + va->vm =3D vm; +} + /* * Allocate a region of KVA of the specified size and alignment, within the - * vstart and vend. + * vstart and vend. If vm is passed in, the two will also be bound. */ static struct vmap_area *alloc_vmap_area(unsigned long size, unsigned long align, unsigned long vstart, unsigned long vend, int node, gfp_t gfp_mask, - unsigned long va_flags) + unsigned long va_flags, struct vm_struct *vm, + unsigned long flags, const void *caller) { struct vmap_node *vn; struct vmap_area *va; @@ -1912,6 +1923,9 @@ static struct vmap_area *alloc_vmap_area(unsigned lon= g size, va->vm =3D NULL; va->flags =3D (va_flags | vn_id); =20 + if (vm) + setup_vmalloc_vm(vm, va, flags, caller); + vn =3D addr_to_node(va->va_start); =20 spin_lock(&vn->busy.lock); @@ -2486,7 +2500,8 @@ static void *new_vmap_block(unsigned int order, gfp_t= gfp_mask) va =3D alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE, VMALLOC_START, VMALLOC_END, node, gfp_mask, - VMAP_RAM|VMAP_BLOCK); + VMAP_RAM|VMAP_BLOCK, NULL, + 0, NULL); if (IS_ERR(va)) { kfree(vb); return ERR_CAST(va); @@ -2843,7 +2858,8 @@ void *vm_map_ram(struct page **pages, unsigned int co= unt, int node) struct vmap_area *va; va =3D alloc_vmap_area(size, PAGE_SIZE, VMALLOC_START, VMALLOC_END, - node, GFP_KERNEL, VMAP_RAM); + node, GFP_KERNEL, VMAP_RAM, + NULL, 0, NULL); if (IS_ERR(va)) return NULL; =20 @@ -2946,26 +2962,6 @@ void __init vm_area_register_early(struct vm_struct = *vm, size_t align) kasan_populate_early_vm_area_shadow(vm->addr, vm->size); } =20 -static inline void setup_vmalloc_vm_locked(struct vm_struct *vm, - struct vmap_area *va, unsigned long flags, const void *caller) -{ - vm->flags =3D flags; - vm->addr =3D (void *)va->va_start; - vm->size =3D va->va_end - va->va_start; - vm->caller =3D caller; - va->vm =3D vm; -} - -static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, - unsigned long flags, const void *caller) -{ - struct vmap_node *vn =3D addr_to_node(va->va_start); - - spin_lock(&vn->busy.lock); - setup_vmalloc_vm_locked(vm, va, flags, caller); - spin_unlock(&vn->busy.lock); -} - static void clear_vm_uninitialized_flag(struct vm_struct *vm) { /* @@ -3002,7 +2998,7 @@ static struct vm_struct *__get_vm_area_node(unsigned = long size, if (!(flags & VM_NO_GUARD)) size +=3D PAGE_SIZE; =20 - va =3D alloc_vmap_area(size, align, start, end, node, gfp_mask, 0); + va =3D alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area, = flags, caller); if (IS_ERR(va)) { kfree(area); return NULL; @@ -4584,7 +4580,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned l= ong *offsets, =20 spin_lock(&vn->busy.lock); insert_vmap_area(vas[area], &vn->busy.root, &vn->busy.head); - setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC, + setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC, pcpu_get_vm_areas); spin_unlock(&vn->busy.lock); } base-commit: c09a8e005eff6c064e2e9f11549966c36a724fbf --=20 2.43.0