From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 D350922D7A1 for ; Thu, 18 Sep 2025 02:56:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758164207; cv=none; b=mMDSMn+1gVqnw6uuB3+kYX5a6gLw4624BsD+VLhdLCDj3/wJt8N/1PCQ6D339DQkaoR7ytcNCwO6Re1G4xToIdopH6rGxYMzUGlQgbUHWZ8HvwZ5HuUKxu8S9DXmvSBt7jtL+8q/C1MamGHgFiVgOQD5XohyE1RdKAzlVXpcwk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758164207; c=relaxed/simple; bh=+EMiM4llLdOoJeufXmSX/4wSF3vMrKuTktW/zGv56CY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kx/jWJZzo9ZwYN+mTJNBDb8yw9H1Zbpjob9nH+JpoaTECqna9vDpL4gy3rpFsrXAr92XYGbpXtn1Uagt03GZIUV2gg6U4TguEZzq6Bkh5/5FQFck62F2W4iKFx+tsJTgxNTamT1P8BkpiyZyQD+FJQg69lRLiNBG15aoh7g6aH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=CdwlPeqV; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CdwlPeqV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758164204; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=G+LtIQpgc290vPRQOhAQlDUbtf58jv7H8SakHmLcEEA=; b=CdwlPeqV9DVNzYZw0Y9JI3AJb2IxzGaYpr+DaZlpcORLHJilVOyut+Za1zFWN9GRdcjVah FRMi6QaFdBVa1pI7ptGqlglRYeJNYoQwh9dcQeM2WHt5gP9UdV7jmA8fWwaNZx3sY/exXt YQlGKLr0wWxX71+TH0QsmsUZJtm36uA= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-595-ZFTlBNNGPc-z9rkq6G2ROA-1; Wed, 17 Sep 2025 22:56:42 -0400 X-MC-Unique: ZFTlBNNGPc-z9rkq6G2ROA-1 X-Mimecast-MFC-AGG-ID: ZFTlBNNGPc-z9rkq6G2ROA_1758164200 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 694F2180034C; Thu, 18 Sep 2025 02:56:40 +0000 (UTC) Received: from localhost (unknown [10.72.112.180]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4C4E61800446; Thu, 18 Sep 2025 02:56:38 +0000 (UTC) Date: Thu, 18 Sep 2025 10:56:35 +0800 From: Baoquan He To: "Uladzislau Rezki (Sony)" Cc: linux-mm@kvack.org, Andrew Morton , Michal Hocko , LKML , Michal Hocko Subject: Re: [PATCH v2 03/10] mm/vmalloc: Support non-blocking GFP flags in alloc_vmap_area() Message-ID: References: <20250915134041.151462-1-urezki@gmail.com> <20250915134041.151462-4-urezki@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250915134041.151462-4-urezki@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On 09/15/25 at 03:40pm, Uladzislau Rezki (Sony) wrote: > alloc_vmap_area() currently assumes that sleeping is allowed during > allocation. This is not true for callers which pass non-blocking > GFP flags, such as GFP_ATOMIC or GFP_NOWAIT. > > This patch adds logic to detect whether the given gfp_mask permits > blocking. It avoids invoking might_sleep() or falling back to reclaim > path if blocking is not allowed. > > This makes alloc_vmap_area() safer for use in non-sleeping contexts, > where previously it could hit unexpected sleeps, trigger warnings. > > It is a preparation and adjustment step to later allow both GFP_ATOMIC > and GFP_NOWAIT allocations in this series. > > Acked-by: Michal Hocko > Signed-off-by: Uladzislau Rezki (Sony) > --- > mm/vmalloc.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) LGTM, Reviewed-by: Baoquan He > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 5edd536ba9d2..49a0f81930a8 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2017,6 +2017,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > unsigned long freed; > unsigned long addr; > unsigned int vn_id; > + bool allow_block; > int purged = 0; > int ret; > > @@ -2028,7 +2029,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > > /* Only reclaim behaviour flags are relevant. */ > gfp_mask = gfp_mask & GFP_RECLAIM_MASK; > - might_sleep(); > + allow_block = gfpflags_allow_blocking(gfp_mask); > + might_sleep_if(allow_block); > > /* > * If a VA is obtained from a global heap(if it fails here) > @@ -2065,8 +2067,16 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > * If an allocation fails, the error value is > * returned. Therefore trigger the overflow path. > */ > - if (IS_ERR_VALUE(addr)) > - goto overflow; > + if (IS_ERR_VALUE(addr)) { > + if (allow_block) > + goto overflow; > + > + /* > + * We can not trigger any reclaim logic because > + * sleeping is not allowed, thus fail an allocation. > + */ > + goto out_free_va; > + } > > va->va_start = addr; > va->va_end = addr + size; > @@ -2116,6 +2126,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > pr_warn("vmalloc_node_range for size %lu failed: Address range restricted to %#lx - %#lx\n", > size, vstart, vend); > > +out_free_va: > kmem_cache_free(vmap_area_cachep, va); > return ERR_PTR(-EBUSY); > } > -- > 2.47.3 >