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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 715D6C55ABF for ; Thu, 6 Aug 2026 01:13:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D86056B00C4; Wed, 5 Aug 2026 21:13:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CE5A96B00C7; Wed, 5 Aug 2026 21:13:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BFBBB6B00C8; Wed, 5 Aug 2026 21:13:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 569D36B00C4 for ; Wed, 5 Aug 2026 21:13:00 -0400 (EDT) Received: from smtpin10.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 5ABDF160646 for ; Thu, 6 Aug 2026 01:12:59 +0000 (UTC) X-FDA: 85069070478.10.4AACDD1 Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by imf01.hostedemail.com (Postfix) with ESMTP id A200940008 for ; Thu, 6 Aug 2026 01:12:57 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=e2xfIybc; spf=pass (imf01.hostedemail.com: domain of 3mN9zagcKCIEo3jxhfxlttlqj.htrqnsz2-rrp0fhp.twl@flex--jyescas.bounces.google.com designates 209.85.214.198 as permitted sender) smtp.mailfrom=3mN9zagcKCIEo3jxhfxlttlqj.htrqnsz2-rrp0fhp.twl@flex--jyescas.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785978777; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=qT2U8sjoXnH+lrEkvLzdxmLHnjH1gE3vQbkqTT4aFL8=; b=vEqPlPry20rTEfdEaGbjl0Rfpcs3z+6aHLrsLhNk3WZlPwUUC+Gmjy9451CmbplX9rkhcW J/V45h2augEJCgEHCWGhRt/SJrEj19/f0hc3l8FhmGPHKwVSwaK1QZ00LVnXTSOWA3AFkb AoJindcPpy+mHqhpxzG37LbtUqolDsg= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785978777; b=5eOatmXrPFM+oCfLwNDUakPUK2Y50XMRZExdppIVz4LnAhK1sehJEh7n7vJxHVV5opVMvK uhBJSjjKR0auepzug78Oj9FpF0vamVtz6M5h7sw42Q9zX6DSebotCFoLg/90AzaRYacK4S IcB2MrHRx1OPPFrg0wKCNLmwufUaW6Q= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=e2xfIybc; spf=pass (imf01.hostedemail.com: domain of 3mN9zagcKCIEo3jxhfxlttlqj.htrqnsz2-rrp0fhp.twl@flex--jyescas.bounces.google.com designates 209.85.214.198 as permitted sender) smtp.mailfrom=3mN9zagcKCIEo3jxhfxlttlqj.htrqnsz2-rrp0fhp.twl@flex--jyescas.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com Received: by mail-pl1-f198.google.com with SMTP id d9443c01a7336-2cacd6d37edso20460825ad.0 for ; Wed, 05 Aug 2026 18:12:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785978776; x=1786583576; darn=kvack.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=qT2U8sjoXnH+lrEkvLzdxmLHnjH1gE3vQbkqTT4aFL8=; b=e2xfIybcKsXZ5Tt2s4DXBHgS0oc25sYitfJ+bB/MDrbLbu9VX9G6nDrD6y/1JllOEb DhXUv7QmNQPfcjVWp7ha60Jx6PEZL15jG3T0iomAErtQPWyB/r53mDavscKCE30jr7j5 dJq9XY3RFADKJzWvaqoTKhjPuRBeZQzsRDiDTKrS9Y1rl3xlwo6kXBRYbsvUzZudZPzk oMAj8haQrt8ENoG6eBuem+jowly8dz0Dg9tIZnMGaCjV15zzyeITaZsZWCJO0vCsvv+4 t66nFskTYL9QRRsWgp52pRgyPwzJzNxSK/VtAwIXnxUhEzfInjGk/ISILWWyc+UrR0jn fZWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785978776; x=1786583576; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=qT2U8sjoXnH+lrEkvLzdxmLHnjH1gE3vQbkqTT4aFL8=; b=HZTv7WxjA5m5PLxiefhEVJZ84L6f4TnviLd9nWgvk+Y481frX/D/MOipO+NOtJBSo5 ksivctb3STGK/ryQHz2hULfkeN3+Fs01VrkdEMqI5feuzyBqlOkWLi3h7jN9tqHcR1Hn /tQpoQtdVuZ30EibEt3f5w7xa3izCuQYs9W69ofgo+REKt+HkfKzku2J+NU4KT5yvToW 7kAUaz0LrOQ6qCjnb6q3kXl+OcjTfDUDLzFNyU64yimrXQXBDI77zwiVHgwksxOe3SoW rA9uD9BJcjXmZrQrycPqVejPhzShNrhKbQQL6fYJSy3+w/0cp5a7s8D8kywxIV1aTTf0 zx+g== X-Forwarded-Encrypted: i=1; AHgh+Roivmq+Y4rs4JrivopfYkJZMjrdv4OEqyJHOmW/tvnn4ebCIZsV6m6WhJ9Snx6z9tbC64dX1Us/TA==@kvack.org X-Gm-Message-State: AOJu0Yz96cHg6wJdOSZ6eg/36e3b7QV+jde0QgutrZI4cvTE/+uL23pu mRNrbfSyLBX7vCE2ACI0zXPgP7Ksoa7QETcEXciDkndmVUV4RkmdARcq4D37Uuppr+wuGeuLOzA 0CYa9LZLtlA== X-Received: from dyctg10.prod.google.com ([2002:a05:693c:3b0a:b0:311:6294:c296]) (user=jyescas job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:41ce:b0:2ce:9c48:22d3 with SMTP id d9443c01a7336-2d0ca75151dmr122948145ad.11.1785978776189; Wed, 05 Aug 2026 18:12:56 -0700 (PDT) Date: Wed, 5 Aug 2026 18:09:13 -0700 In-Reply-To: <20260806011048.517229-1-jyescas@google.com> Mime-Version: 1.0 References: <20260806011048.517229-1-jyescas@google.com> X-Mailer: git-send-email 2.55.0.629.g250fe7f194-goog Message-ID: <20260806011048.517229-13-jyescas@google.com> Subject: [RFC PATCH v2 12/16] mm: Define the make_alloc() function From: Juan Yescas To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , open list , "open list:MEMORY MANAGEMENT - CORE" Cc: jyescas@google.com, android-mm@google.com, ljs@kernel.org, fvdl@google.com, tkjos@google.com, minchan@google.com, dskiba@google.com, open list , "open list:MEMORY MANAGEMENT - CORE" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: A200940008 X-Stat-Signature: wxq5b89a118cxeo76f1eyi6357qs19pi X-Rspam-User: X-HE-Tag: 1785978777-961429 X-HE-Meta: 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 uUfjZ4xM 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The make_alloc() is the core function that performs the allocation. The tasks of this function are: - Call the Buddy allocator to make the allocation. - Store the details of the allocation in struct page_alloc. - Insert the struct page_alloc in an xarray using the allocation id as key. If something fails during the allocation, the pages and cache will be freed. Signed-off-by: Juan Yescas --- Changes in v2: - Once that page_alloc is initialized, insert it in xarray. - Use 20 characters for the file name instead of 12. - Fix use-after-free issue while releasing the pages. mm/page_alloc_hogger.c | 72 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) diff --git a/mm/page_alloc_hogger.c b/mm/page_alloc_hogger.c index 4b72acfbc087..e22247b7bd98 100644 --- a/mm/page_alloc_hogger.c +++ b/mm/page_alloc_hogger.c @@ -96,6 +96,18 @@ static struct dentry *mmdir; +/** + * atomic_long_t allocs_file_seq - Represents the naming sequence used for + * allocation files. + */ +static atomic_long_t allocs_file_seq = ATOMIC_INIT(0); + +/** + * allocs_xa - Represent the xarray that contains the actual allocations perform + * by this driver. + */ +static DEFINE_XARRAY(allocs_xa); + /** * struct req_alloc - Represents the requested allocation * @node_idx: The Node index to allocate from. @@ -173,6 +185,47 @@ static inline void set_migrate_type_to_alloc_from(int migrate_type, gfp_t *flags } } +static int make_alloc(struct req_alloc *req, + gfp_t flags, unsigned long *alloc_id) +{ + struct page_alloc *pa; + struct page *page; + char new_alloc_name[20]; + int ret; + + page = alloc_pages_node_noprof(req->node_idx, flags, req->order); + if (page) { + pa = kmem_cache_alloc(page_alloc_cache, GFP_KERNEL); + if (!pa) { + ret = -ENOMEM; + goto free_pages; + } + + *alloc_id = atomic_long_inc_return(&allocs_file_seq); + snprintf(new_alloc_name, sizeof(new_alloc_name), "%lu", + *alloc_id); + + pa->req_alloc = req; + pa->page = page; + + ret = xa_insert(&allocs_xa, *alloc_id, pa, GFP_KERNEL); + if (ret) + goto free_page_alloc; + } else { + return -ENOMEM; + } + + return 0; + +free_page_alloc: + kmem_cache_free(page_alloc_cache, pa); + +free_pages: + __free_pages(page, req->order); + + return ret; +} + /** * req_page_alloc_write() - Allocates the pages on the requested node, zone, * order and migrate type. Once the allocation is performed, a file is created @@ -182,10 +235,12 @@ static ssize_t req_page_alloc_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct req_alloc *req = file->private_data; + unsigned long alloc_id; unsigned long nr_pages_allocs; unsigned long *allocs_ids; gfp_t flags = 0; int ret; + int i; ret = kstrtoul_from_user(ubuf, cnt, 10, &nr_pages_allocs); if (ret) @@ -199,9 +254,26 @@ static ssize_t req_page_alloc_write(struct file *file, const char __user *ubuf, set_zone_to_alloc_from(req->zone_idx, &flags); set_migrate_type_to_alloc_from(req->migrate_type, &flags); + for (i = 0; i < nr_pages_allocs; i++) { + ret = make_alloc(req, flags, &alloc_id); + if (ret) + goto free_allocs; + + allocs_ids[i] = alloc_id; + } + kfree(allocs_ids); return cnt; + +free_allocs: + /* + * A proper clean up of the pages and page_alloc allocations will + * be done in a follow up patch of this topic. + */ + kfree(allocs_ids); + + return ret; } static const struct file_operations req_page_alloc_fops = { -- 2.55.0.629.g250fe7f194-goog