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Tue, 08 Nov 2022 22:35:46 -0500 X-MC-Unique: vGWf6ADhPLuE-5SDkR8Wmw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5C8AA101A52A; Wed, 9 Nov 2022 03:35:46 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-86.pek2.redhat.com [10.72.12.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id D78E610197; Wed, 9 Nov 2022 03:35:42 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, stephen.s.brennan@oracle.com, urezki@gmail.com, hch@infradead.org, Baoquan He Subject: [PATCH RFC 1/3] mm/vmalloc.c: add used_map into vmap_block to track space of vmap_block Date: Wed, 9 Nov 2022 11:35:32 +0800 Message-Id: <20221109033535.269229-2-bhe@redhat.com> In-Reply-To: <20221109033535.269229-1-bhe@redhat.com> References: <20221109033535.269229-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 ARC-Message-Signature: i=1; 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dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=H2J8bDIz; spf=pass (imf20.hostedemail.com: domain of bhe@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=bhe@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: ujkpss8cir8eu6dcf6gphs3fwkkg17u5 X-HE-Tag: 1667964998-17349 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: In one vmap_block area, there could be three types of regions: used region which is allocated through vb_alloc(), dirty region which is freed through vb_free() and free region. Among them, only used region has available data, while there's no way to track those used regions currently. Here, add bitmap field used_map into vmap_block, and set/clear it during allocation or freeing regions of vmap_block area. This is a preparatoin for later use. Signed-off-by: Baoquan He --- mm/vmalloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ccaa461998f3..5d3fd3e6fe09 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1896,6 +1896,7 @@ struct vmap_block { spinlock_t lock; struct vmap_area *va; unsigned long free, dirty; + DECLARE_BITMAP(used_map, VMAP_BBMAP_BITS); unsigned long dirty_min, dirty_max; /*< dirty range */ struct list_head free_list; struct rcu_head rcu_head; @@ -1972,10 +1973,12 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) vb->va = va; /* At least something should be left free */ BUG_ON(VMAP_BBMAP_BITS <= (1UL << order)); + bitmap_zero(vb->used_map, VMAP_BBMAP_BITS); vb->free = VMAP_BBMAP_BITS - (1UL << order); vb->dirty = 0; vb->dirty_min = VMAP_BBMAP_BITS; vb->dirty_max = 0; + bitmap_set(vb->used_map, 0, (1UL << order)); INIT_LIST_HEAD(&vb->free_list); vb_idx = addr_to_vb_idx(va->va_start); @@ -2081,6 +2084,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) pages_off = VMAP_BBMAP_BITS - vb->free; vaddr = vmap_block_vaddr(vb->va->va_start, pages_off); vb->free -= 1UL << order; + bitmap_set(vb->used_map, pages_off, (1UL << order)); if (vb->free == 0) { spin_lock(&vbq->lock); list_del_rcu(&vb->free_list); @@ -2114,6 +2118,9 @@ static void vb_free(unsigned long addr, unsigned long size) order = get_order(size); offset = (addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT; vb = xa_load(&vmap_blocks, addr_to_vb_idx(addr)); + spin_lock(&vb->lock); + bitmap_clear(vb->used_map, offset, (1UL << order)); + spin_unlock(&vb->lock); vunmap_range_noflush(addr, addr + size); From patchwork Wed Nov 9 03:35:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 13037135 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F02E6C433FE for ; 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Wed, 9 Nov 2022 03:35:50 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-86.pek2.redhat.com [10.72.12.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2D7AB10197; Wed, 9 Nov 2022 03:35:46 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, stephen.s.brennan@oracle.com, urezki@gmail.com, hch@infradead.org, Baoquan He Subject: [PATCH RFC 2/3] mm/vmalloc.c: add flags to mark vm_map_ram area Date: Wed, 9 Nov 2022 11:35:33 +0800 Message-Id: <20221109033535.269229-3-bhe@redhat.com> In-Reply-To: <20221109033535.269229-1-bhe@redhat.com> References: <20221109033535.269229-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667965010; a=rsa-sha256; cv=none; b=kvafPkQzT30fCeyRx+YLYGGVCC0yj/ScbtgOqPeTLRF9EkdmcW/aQg5PJSDsRVYSvUEj7W iFBxmBlfsoRoB4cA8GN6XvDcAG4eggnJaxMmfooF1w7U9sYkcfp88vXU80HQoQScyqIPrF /LM0ZCov5J6jn+jeZDi06CZhtaumJxQ= ARC-Authentication-Results: i=1; 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dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ilg2EUFm; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf13.hostedemail.com: domain of bhe@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=bhe@redhat.com X-Rspamd-Server: rspam03 X-HE-Tag: 1667965010-879044 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: Through vmalloc API, a virtual kernel area is reserved for physical address mapping. And vmap_area is used to track them, and vm_struct is allocated to associate with the vmap_area to store more information and passed out. However, area reserved via vm_map_ram() is an exception. It doesn't have vm_struct to associate with vmap_area. And we can't simply recognize the vm_map_ram areas with '->vm == NULL' because the normal freeing path will set va->vm = NULL before unmapping, please see function remove_vm_area(). Meanwhile, there are two types of vm_map_ram area. One is the whole vmap_area being reserved and mapped at one time; the other is the whole vmap_area with VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with smaller size several times. To mark the area reserved through vm_map_ram(), add flags into the union field of struct vmap_area to reuse the space since that union space is free anyway if it's vm_map_ram area. This is a preparatoin for later use. Signed-off-by: Baoquan He --- include/linux/vmalloc.h | 1 + mm/vmalloc.c | 17 ++++++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48aa3437..b739a60b73da 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -75,6 +75,7 @@ struct vmap_area { union { unsigned long subtree_max_size; /* in "free" tree */ struct vm_struct *vm; /* in "busy" tree */ + unsigned long flags; /* mark type of vm_map_ram area */ }; }; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5d3fd3e6fe09..41d82dc07e13 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1815,6 +1815,7 @@ static void free_vmap_area_noflush(struct vmap_area *va) spin_lock(&vmap_area_lock); unlink_va(va, &vmap_area_root); + va->flags = 0; spin_unlock(&vmap_area_lock); nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >> @@ -1887,6 +1888,9 @@ struct vmap_area *find_vmap_area(unsigned long addr) #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) +#define VMAP_RAM 0x1 +#define VMAP_BLOCK 0x2 + struct vmap_block_queue { spinlock_t lock; struct list_head free; @@ -1967,6 +1971,9 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) kfree(vb); return ERR_CAST(va); } + spin_lock(&vmap_area_lock); + va->flags = VMAP_RAM|VMAP_BLOCK; + spin_unlock(&vmap_area_lock); vaddr = vmap_block_vaddr(va->va_start, 0); spin_lock_init(&vb->lock); @@ -2229,8 +2236,12 @@ void vm_unmap_ram(const void *mem, unsigned int count) return; } - va = find_vmap_area(addr); + spin_lock(&vmap_area_lock); + va = __find_vmap_area((unsigned long)addr, &vmap_area_root); BUG_ON(!va); + if (va) + va->flags &= ~VMAP_RAM; + spin_unlock(&vmap_area_lock); debug_check_no_locks_freed((void *)va->va_start, (va->va_end - va->va_start)); free_unmap_vmap_area(va); @@ -2269,6 +2280,10 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) if (IS_ERR(va)) return NULL; + spin_lock(&vmap_area_lock); + va->flags = VMAP_RAM; + spin_unlock(&vmap_area_lock); + addr = va->va_start; mem = (void *)addr; } From patchwork Wed Nov 9 03:35:34 2022 Content-Type: text/plain; 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Tue, 08 Nov 2022 22:35:55 -0500 X-MC-Unique: p_3NSPWfPiGGUfTsv4bsoQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 616DD811E67; Wed, 9 Nov 2022 03:35:55 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-86.pek2.redhat.com [10.72.12.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id A9D6C7AE5; Wed, 9 Nov 2022 03:35:51 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, stephen.s.brennan@oracle.com, urezki@gmail.com, hch@infradead.org, Baoquan He Subject: [PATCH RFC 3/3] mm/vmalloc.c: allow vread() to read out vm_map_ram areas Date: Wed, 9 Nov 2022 11:35:34 +0800 Message-Id: <20221109033535.269229-4-bhe@redhat.com> In-Reply-To: <20221109033535.269229-1-bhe@redhat.com> References: <20221109033535.269229-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 ARC-Seal: i=1; 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dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=QtMqU1jz; spf=pass (imf03.hostedemail.com: domain of bhe@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=bhe@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: fbfbxoo4bjjbap8y9ifjtbyyqzbqg3zm X-Rspamd-Queue-Id: 8BE7520004 X-HE-Tag: 1667965000-180990 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: Currently, vread() can read out vmalloc areas which is associated with a vm_struct. While this doesn't work for areas created by vm_map_ram() interface because it doesn't allocate a vm_struct. Then in vread(), these areas will be skipped. Here, add a new function vb_vread() to read out areas managed by vmap_block specifically. Then recognize vm_map_ram areas via vmap->flags and handle them respectively. Stephen Brennan Signed-off-by: Baoquan He Link: https://lore.kernel.org/all/87ilk6gos2.fsf@oracle.com/T/#u --- mm/vmalloc.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 6 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 41d82dc07e13..5a8d5659bfb0 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3518,6 +3518,46 @@ static int aligned_vread(char *buf, char *addr, unsigned long count) return copied; } +static void vb_vread(char *buf, char *addr, int count) +{ + char *start; + struct vmap_block *vb; + unsigned long offset; + unsigned int rs, re, n; + + offset = ((unsigned long)addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT; + vb = xa_load(&vmap_blocks, addr_to_vb_idx((unsigned long)addr)); + + spin_lock(&vb->lock); + if (bitmap_empty(vb->used_map, VMAP_BBMAP_BITS)) { + spin_unlock(&vb->lock); + memset(buf, 0, count); + return; + } + for_each_set_bitrange(rs, re, vb->used_map, VMAP_BBMAP_BITS) { + if (!count) + break; + start = vmap_block_vaddr(vb->va->va_start, rs); + if (addr < start) { + if (count == 0) + break; + *buf = '\0'; + buf++; + addr++; + count--; + } + n = (re - rs + 1) << PAGE_SHIFT; + if (n > count) + n = count; + aligned_vread(buf, start, n); + + buf += n; + addr += n; + count -= n; + } + spin_unlock(&vb->lock); +} + /** * vread() - read vmalloc area in a safe way. * @buf: buffer for reading data @@ -3548,7 +3588,7 @@ long vread(char *buf, char *addr, unsigned long count) struct vm_struct *vm; char *vaddr, *buf_start = buf; unsigned long buflen = count; - unsigned long n; + unsigned long n, size; addr = kasan_reset_tag(addr); @@ -3569,12 +3609,14 @@ long vread(char *buf, char *addr, unsigned long count) if (!count) break; - if (!va->vm) + if (!(va->flags & VMAP_RAM) && !va->vm) continue; vm = va->vm; - vaddr = (char *) vm->addr; - if (addr >= vaddr + get_vm_area_size(vm)) + vaddr = (char *) va->va_start; + size = vm ? get_vm_area_size(vm) : va_size(va); + + if (addr >= vaddr + size) continue; while (addr < vaddr) { if (count == 0) @@ -3584,10 +3626,13 @@ long vread(char *buf, char *addr, unsigned long count) addr++; count--; } - n = vaddr + get_vm_area_size(vm) - addr; + n = vaddr + size - addr; if (n > count) n = count; - if (!(vm->flags & VM_IOREMAP)) + + if ((va->flags & (VMAP_RAM|VMAP_BLOCK)) == (VMAP_RAM|VMAP_BLOCK)) + vb_vread(buf, addr, n); + else if ((va->flags & VMAP_RAM) || !(vm->flags & VM_IOREMAP)) aligned_vread(buf, addr, n); else /* IOREMAP area is treated as memory hole */ memset(buf, 0, n);