From nobody Sun Feb 8 05:38:33 2026 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 093AA18B494 for ; Tue, 30 Jul 2024 18:50:59 +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=1722365460; cv=none; b=LCS7CKJBKQnoNIuc/N/nMknDnCULAKAnHuvmYUH0Hre76sZfHM9A1TwSoPi1+FUUTsPp5sl2OvFCRr9rxizxtVgewApWLJxuq6lcdO3CH0/4fcNmMBrc35o03xU7qMSc+zsD7KTBLMChCauHz1MgWnXrerlsudLyRmGKZBGZVuc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722365460; c=relaxed/simple; bh=pqmv76F1WcFutmWjI3wHquYQ2ukivLAaozJiVBwDm7M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i85Kb95LBWXMjqO87xGfFGNI7/Tm4J7aT+LURq+sZIxJPT0O37fDkXSBK3wyX04NEGhxT33ELWSdDaZmSKd6Ah5yJnLD1B098w9P2KkWjTRRdodWVGpQjCZ+xxsXYlQKoliwZv9D12FTbH+JX33kfjag2lwbMuCDoUEHv1VUnns= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AOgF+9qB; 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="AOgF+9qB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C974BC4AF0A; Tue, 30 Jul 2024 18:50:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722365459; bh=pqmv76F1WcFutmWjI3wHquYQ2ukivLAaozJiVBwDm7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AOgF+9qBGFqKxJ8z4A6PgTFI5uYlUNekNx9SPS/SqWo35zBpPaiN87qT3ktO1zdzc QMYeHnTcqQxbUhysQGYmIJuey8q1zASAdVZHZpDbQ4KXgeW8lS5IAeIzAW5X/JpYj0 b7QuzOIKrpAu8L5rZHQzMcFcCt7JqP852MttQgYl1iRORwFDUhmGoLvRzpOjR6etsA XrX9PPOBBOMCeKCm517hKCADyt6UPMZwI+v7THiGeG8m4+I1h7XwuwyfVv6zs0JqLW 6pQZCszlfzoYzSgVnhz4MwQ1sQJINCMAjFtLcTETveHdGHdo7+v/nb1ukBSVJrfJKt EpnCk755lK3gA== From: Danilo Krummrich To: akpm@linux-foundation.org, urezki@gmail.com, hch@infradead.org, vbabka@suse.cz Cc: mhocko@suse.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Danilo Krummrich Subject: [PATCH 2/4] mm: vrealloc: consider spare memory for __GFP_ZERO Date: Tue, 30 Jul 2024 20:49:42 +0200 Message-ID: <20240730185049.6244-3-dakr@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240730185049.6244-1-dakr@kernel.org> References: <20240730185049.6244-1-dakr@kernel.org> 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" Zero spare memory when shrinking a buffer with __GFP_ZERO. Fixes: 1f39ee9615a8 ("mm: vmalloc: implement vrealloc()") Signed-off-by: Danilo Krummrich --- mm/vmalloc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 2a6d4ce57b73..6a2fef6378e4 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4077,12 +4077,15 @@ void *vrealloc_noprof(const void *p, size_t size, g= fp_t flags) old_size =3D get_vm_area_size(vm); } =20 + /* + * TODO: Shrink the vm_area, i.e. unmap and free unused pages. What + * would be a good heuristic for when to shrink the vm_area? + */ if (size <=3D old_size) { - /* - * TODO: Shrink the vm_area, i.e. unmap and free unused pages. - * What would be a good heuristic for when to shrink the - * vm_area? - */ + /* Zero out spare memory. */ + if (want_init_on_alloc(flags)) + memset((void *)p + size, 0, old_size - size); + return (void *)p; } =20 --=20 2.45.2