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[67.231.145.42]) by mx.google.com with ESMTPS id x141si298963pgx.1.2019.05.14.16.51.18 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 14 May 2019 16:51:18 -0700 (PDT) Received-SPF: pass (google.com: domain of prvs=0037dedd0e=guro@fb.com designates 67.231.145.42 as permitted sender) client-ip=67.231.145.42; Authentication-Results: mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b=nS5cBo7Z; spf=pass (google.com: domain of prvs=0037dedd0e=guro@fb.com designates 67.231.145.42 as permitted sender) smtp.mailfrom="prvs=0037dedd0e=guro@fb.com"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4ENhWmx001629 for ; Tue, 14 May 2019 16:51:17 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=facebook; bh=O7eBrs0cmRrFsnBiCjlPOjGDWGcxOa5jMCEdxURKIS8=; b=nS5cBo7ZXbIbW8vKlx1+2CYmEYbH/oukpPAEDPubpR6q6i6Kmz3pt45EkxkZ7GSqbzZu P8S1VqFOtaBkglV9zxTsxNw/5rFS0/BS6JglBD+487wPVRGDPfweYpl1cbATdH47RDSn PwPBysBeuv/hXDcbOdZ1G0FUwCEP1g+e2jw= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2sg3k1gvtn-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 14 May 2019 16:51:17 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::127) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Tue, 14 May 2019 16:51:16 -0700 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id E085912084F48; Tue, 14 May 2019 16:51:15 -0700 (PDT) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: Andrew Morton CC: , , , Johannes Weiner , Roman Gushchin , Matthew Wilcox , Vlastimil Babka Smtp-Origin-Cluster: prn2c23 Subject: [PATCH] mm: refactor __vunmap() to avoid duplicated call to find_vm_area() Date: Tue, 14 May 2019 16:51:10 -0700 Message-ID: <20190514235111.2817276-1-guro@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-14_13:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: __vunmap() calls find_vm_area() twice without an obvious reason: first directly to get the area pointer, second indirectly by calling vm_remove_mappings()->remove_vm_area(), which is again searching for the area. To remove this redundancy, let's split remove_vm_area() into __remove_vm_area(struct vmap_area *), which performs the actual area removal, and remove_vm_area(const void *addr) wrapper, which can be used everywhere, where it has been used before. Let's pass a pointer to the vm_area instead of vm_struct to vm_remove_mappings(), so it can pass it to __remove_vm_area() and avoid the redundant area lookup. On my test setup, I've got 5-10% speed up on vfree()'ing 1000000 of 4-pages vmalloc blocks. Perf report before: 29.44% cat [kernel.kallsyms] [k] free_unref_page 11.88% cat [kernel.kallsyms] [k] find_vmap_area 9.28% cat [kernel.kallsyms] [k] __free_pages 7.44% cat [kernel.kallsyms] [k] __slab_free 7.28% cat [kernel.kallsyms] [k] vunmap_page_range 4.56% cat [kernel.kallsyms] [k] __vunmap 3.64% cat [kernel.kallsyms] [k] __purge_vmap_area_lazy 3.04% cat [kernel.kallsyms] [k] __free_vmap_area Perf report after: 32.41% cat [kernel.kallsyms] [k] free_unref_page 7.79% cat [kernel.kallsyms] [k] find_vmap_area 7.40% cat [kernel.kallsyms] [k] __slab_free 7.31% cat [kernel.kallsyms] [k] vunmap_page_range 6.84% cat [kernel.kallsyms] [k] __free_pages 6.01% cat [kernel.kallsyms] [k] __vunmap 3.98% cat [kernel.kallsyms] [k] smp_call_function_single 3.81% cat [kernel.kallsyms] [k] __purge_vmap_area_lazy 2.77% cat [kernel.kallsyms] [k] __free_vmap_area Signed-off-by: Roman Gushchin Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Vlastimil Babka --- mm/vmalloc.c | 52 +++++++++++++++++++++++++++++----------------------- 1 file changed, 29 insertions(+), 23 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index c42872ed82ac..8d4907865614 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2075,6 +2075,22 @@ struct vm_struct *find_vm_area(const void *addr) return NULL; } +static struct vm_struct *__remove_vm_area(struct vmap_area *va) +{ + struct vm_struct *vm = va->vm; + + spin_lock(&vmap_area_lock); + va->vm = NULL; + va->flags &= ~VM_VM_AREA; + va->flags |= VM_LAZY_FREE; + spin_unlock(&vmap_area_lock); + + kasan_free_shadow(vm); + free_unmap_vmap_area(va); + + return vm; +} + /** * remove_vm_area - find and remove a continuous kernel virtual area * @addr: base address @@ -2087,26 +2103,14 @@ struct vm_struct *find_vm_area(const void *addr) */ struct vm_struct *remove_vm_area(const void *addr) { + struct vm_struct *vm = NULL; struct vmap_area *va; - might_sleep(); - va = find_vmap_area((unsigned long)addr); - if (va && va->flags & VM_VM_AREA) { - struct vm_struct *vm = va->vm; - - spin_lock(&vmap_area_lock); - va->vm = NULL; - va->flags &= ~VM_VM_AREA; - va->flags |= VM_LAZY_FREE; - spin_unlock(&vmap_area_lock); - - kasan_free_shadow(vm); - free_unmap_vmap_area(va); + if (va && va->flags & VM_VM_AREA) + vm = __remove_vm_area(va); - return vm; - } - return NULL; + return vm; } static inline void set_area_direct_map(const struct vm_struct *area, @@ -2119,9 +2123,10 @@ static inline void set_area_direct_map(const struct vm_struct *area, set_direct_map(area->pages[i]); } -/* Handle removing and resetting vm mappings related to the vm_struct. */ -static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) +/* Handle removing and resetting vm mappings related to the va->vm vm_struct. */ +static void vm_remove_mappings(struct vmap_area *va, int deallocate_pages) { + struct vm_struct *area = va->vm; unsigned long addr = (unsigned long)area->addr; unsigned long start = ULONG_MAX, end = 0; int flush_reset = area->flags & VM_FLUSH_RESET_PERMS; @@ -2138,7 +2143,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) set_memory_rw(addr, area->nr_pages); } - remove_vm_area(area->addr); + __remove_vm_area(va); /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */ if (!flush_reset) @@ -2178,6 +2183,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) static void __vunmap(const void *addr, int deallocate_pages) { struct vm_struct *area; + struct vmap_area *va; if (!addr) return; @@ -2186,17 +2192,18 @@ static void __vunmap(const void *addr, int deallocate_pages) addr)) return; - area = find_vm_area(addr); - if (unlikely(!area)) { + va = find_vmap_area((unsigned long)addr); + if (unlikely(!va || !(va->flags & VM_VM_AREA))) { WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n", addr); return; } + area = va->vm; debug_check_no_locks_freed(area->addr, get_vm_area_size(area)); debug_check_no_obj_freed(area->addr, get_vm_area_size(area)); - vm_remove_mappings(area, deallocate_pages); + vm_remove_mappings(va, deallocate_pages); if (deallocate_pages) { int i; @@ -2212,7 +2219,6 @@ static void __vunmap(const void *addr, int deallocate_pages) } kfree(area); - return; } static inline void __vfree_deferred(const void *addr) -- 2.20.1