From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1F18B2DECD2 for ; Mon, 5 Jan 2026 17:52:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767635545; cv=none; b=PLSJKRZT4bklBcr0z4FDX9ZfwXrU+LOfRGoYSc/Xy52OqiuJ10hXRf9oxutmc0C9c6TP/mCJcPXWFuHZPWTuEaqvIYiyNS1KEB050yvkcQM9QeS+Sbfrnb3qRRPBsGCYCJgxZJoCuFDfXr/0vF1HG2STCGw/4IuE8Zy/CgvQELI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767635545; c=relaxed/simple; bh=WzH0yhiuWbiDM2XmbVawTKy1GxthlJDMGwEwZkWfSko=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DdIsREpWVspO9OaIs3ehyK0mdhnPI39i4U1Uy+qS6QvVpPMdovu2wLW42cP7Wp7OL4fNJDK/6KKydpXj7MwZFdhv8PQEXRdj5HJY/9MDakoS1mIYW7LvG90bDvlEjZlnXGsNluGDuLUN3gVjsNZQmIummUFUPk1wwrCqHAb++Eo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IQHwkfZy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IQHwkfZy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CB2BC19424; Mon, 5 Jan 2026 17:52:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767635543; bh=WzH0yhiuWbiDM2XmbVawTKy1GxthlJDMGwEwZkWfSko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IQHwkfZywhQjWVncJOtvNwMyWCrwlGCPlpBX9/XoO1Ti2qpIs1jPreAPaO+htA5Vk dmyAGFPHrJwZ4+0DvstNMo5Klmf31PcDsLi0JXlcRahoDv+PhZnfB5i6gV456RoqFu Tf3VnIVF+lLG6W88n3atdiFnwb9jWkQgOTm9Fpa+aif9EFAQq5X6fD3KUlSjCmi02R tZChR4wtDWEm/PA7a8ErJhBFd/obiIW28O1Fyj32bWgKHnUlWxrAYzsPa1Swjj6f1X z/dXOQCBQxAawk9pDmpYylZsgN5nsxPiU6/gspvfVMSIxEbVWgb984InjqQXdYtv9i fClaR197cbjyg== From: Sasha Levin To: stable@vger.kernel.org Cc: David Hildenbrand , Lorenzo Stoakes , Alistair Popple , Al Viro , Arnd Bergmann , Brendan Jackman , Byungchul Park , Chengming Zhou , Christian Brauner , Christophe Leroy , =?UTF-8?q?Eugenio=20P=C3=A9=20rez?= , Greg Kroah-Hartman , Gregory Price , Harry Yoo , "Huang, Ying" , Jan Kara , Jason Gunthorpe , Jason Wang , Jerrin Shaji George , Johannes Weiner , John Hubbard , Jonathan Corbet , Joshua Hahn , Liam Howlett , Madhavan Srinivasan , Mathew Brost , "Matthew Wilcox (Oracle)" , Miaohe Lin , Michael Ellerman , "Michael S. Tsirkin" , Michal Hocko , Mike Rapoport , Minchan Kim , Naoya Horiguchi , Nicholas Piggin , Oscar Salvador , Peter Xu , Qi Zheng , Rakie Kim , Rik van Riel , Sergey Senozhatsky , Shakeel Butt , Suren Baghdasaryan , Vlastimil Babka , Xuan Zhuo , xu xin , Zi Yan , Andrew Morton , Sasha Levin Subject: [PATCH 6.6.y 2/3] mm/balloon_compaction: convert balloon_page_delete() to balloon_page_finalize() Date: Mon, 5 Jan 2026 12:52:11 -0500 Message-ID: <20260105175213.2699504-2-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260105175213.2699504-1-sashal@kernel.org> References: <2026010547-ninth-clinking-d127@gregkh> <20260105175213.2699504-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: David Hildenbrand [ Upstream commit 15504b1163007bbfbd9a63460d5c14737c16e96d ] Let's move the removal of the page from the balloon list into the single caller, to remove the dependency on the PG_isolated flag and clarify locking requirements. Note that for now, balloon_page_delete() was used on two paths: (1) Removing a page from the balloon for deflation through balloon_page_list_dequeue() (2) Removing an isolated page from the balloon for migration in the per-driver migration handlers. Isolated pages were already removed from the balloon list during isolation. So instead of relying on the flag, we can just distinguish both cases directly and handle it accordingly in the caller. We'll shuffle the operations a bit such that they logically make more sense (e.g., remove from the list before clearing flags). In balloon migration functions we can now move the balloon_page_finalize() out of the balloon lock and perform the finalization just before dropping the balloon reference. Document that the page lock is currently required when modifying the movability aspects of a page; hopefully we can soon decouple this from the page lock. Link: https://lkml.kernel.org/r/20250704102524.326966-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: Harry Yoo Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Sergey Senozhatsky Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton Stable-dep-of: 0da2ba35c0d5 ("powerpc/pseries/cmm: adjust BALLOON_MIGRATE when migrating pages") Signed-off-by: Sasha Levin --- arch/powerpc/platforms/pseries/cmm.c | 2 +- drivers/misc/vmw_balloon.c | 3 +- drivers/virtio/virtio_balloon.c | 4 +-- include/linux/balloon_compaction.h | 43 +++++++++++----------------- mm/balloon_compaction.c | 3 +- 5 files changed, 21 insertions(+), 34 deletions(-) diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 5f4037c1d7fe..5e0a718d1be7 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -532,7 +532,6 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info, spin_lock_irqsave(&b_dev_info->pages_lock, flags); balloon_page_insert(b_dev_info, newpage); - balloon_page_delete(page); b_dev_info->isolated_pages--; spin_unlock_irqrestore(&b_dev_info->pages_lock, flags); @@ -542,6 +541,7 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info, */ plpar_page_set_active(page); + balloon_page_finalize(page); /* balloon page list reference */ put_page(page); diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 9ce9b9e0e9b6..ad41e9af8102 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1789,8 +1789,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * @pages_lock . We keep holding @comm_lock since we will need it in a * second. */ - balloon_page_delete(page); - + balloon_page_finalize(page); put_page(page); /* Inflate */ diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 2d5d252ef419..6cb7ccb21b71 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -789,15 +789,13 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, tell_host(vb, vb->inflate_vq); /* balloon's page migration 2nd step -- deflate "page" */ - spin_lock_irqsave(&vb_dev_info->pages_lock, flags); - balloon_page_delete(page); - spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; set_page_pfns(vb, vb->pfns, page); tell_host(vb, vb->deflate_vq); mutex_unlock(&vb->balloon_lock); + balloon_page_finalize(page); put_page(page); /* balloon reference */ return MIGRATEPAGE_SUCCESS; diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 5ca2d5699620..b9f19da37b08 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -97,27 +97,6 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon, list_add(&page->lru, &balloon->pages); } -/* - * balloon_page_delete - delete a page from balloon's page list and clear - * the page->private assignement accordingly. - * @page : page to be released from balloon's page list - * - * Caller must ensure the page is locked and the spin_lock protecting balloon - * pages list is held before deleting a page from the balloon device. - */ -static inline void balloon_page_delete(struct page *page) -{ - __ClearPageOffline(page); - __ClearPageMovable(page); - set_page_private(page, 0); - /* - * No touch page.lru field once @page has been isolated - * because VM is using the field. - */ - if (!PageIsolated(page)) - list_del(&page->lru); -} - /* * balloon_page_device - get the b_dev_info descriptor for the balloon device * that enqueues the given page. @@ -141,12 +120,6 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon, list_add(&page->lru, &balloon->pages); } -static inline void balloon_page_delete(struct page *page) -{ - __ClearPageOffline(page); - list_del(&page->lru); -} - static inline gfp_t balloon_mapping_gfp_mask(void) { return GFP_HIGHUSER; @@ -154,6 +127,22 @@ static inline gfp_t balloon_mapping_gfp_mask(void) #endif /* CONFIG_BALLOON_COMPACTION */ +/* + * balloon_page_finalize - prepare a balloon page that was removed from the + * balloon list for release to the page allocator + * @page: page to be released to the page allocator + * + * Caller must ensure that the page is locked. + */ +static inline void balloon_page_finalize(struct page *page) +{ + if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) { + __ClearPageMovable(page); + set_page_private(page, 0); + } + __ClearPageOffline(page); +} + /* * balloon_page_push - insert a page into a page list. * @head : pointer to list diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index dafb7dc90cfd..2a7dabab4533 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -93,7 +93,8 @@ size_t balloon_page_list_dequeue(struct balloon_dev_info *b_dev_info, if (!trylock_page(page)) continue; - balloon_page_delete(page); + list_del(&page->lru); + balloon_page_finalize(page); __count_vm_event(BALLOON_DEFLATE); list_add(&page->lru, pages); unlock_page(page); -- 2.51.0