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 2FF50173 for ; Mon, 18 Aug 2025 02:11:43 +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=1755483106; cv=none; b=iOJ9YuvTt9rjyOGMnisiZV0Ga73rGAJLoCSsFYGZkUbyZK89f8DzzE2fT6YxfsmEPEMag4P4+1TzWor9bP2M9/9hBAAurXhag7jDWNI40dRDp3WCeScbQpV1e5XhvxmmNEru23Dt/MjkG+OeCVQZ5m9lndD60R8ZndtHCQmzbIA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755483106; c=relaxed/simple; bh=SenFREccRBQwuu5FcLoyKJL536sEWP4+IuB34wFrpwI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C7f7eUPb3Z6PO0tkZR3BkIKkpvwobTCjPVoNm3ZJCiU2yf8fwEZf8D4L1c0WUUtWG6JB2N8srzslTrVRUR1T12XhWj6ZNaFwtoAbiPGMlSxV1btENhBcSalPNd0xMqMKfv473not6VkHdLZERMsSNAokrRmI1vcOt/DBvBoCwsI= 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=OXWB7Ud1; 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="OXWB7Ud1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755483102; 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=6PvPEiL4l8R+WkwNrKmIb0X3D3X7fpJqzrNANmrqZWI=; b=OXWB7Ud17YoNnFb2vnrK9BABVS6YxB+0J6OkqPGWCuJXB612dzgCdFnjQEGtHOiCHx2hkM QccF5Vc0xAV4v2KBh8cm3QtB5vFAi84/qxrzz4tSard0q6jjlrMRuQ7u6tlyfgH4MGGUnS lqig1feWar4+LE+EAqVPkWiFUZ3upHQ= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-217-eOV7kcwiMBi0eXrB3VzXhg-1; Sun, 17 Aug 2025 22:11:39 -0400 X-MC-Unique: eOV7kcwiMBi0eXrB3VzXhg-1 X-Mimecast-MFC-AGG-ID: eOV7kcwiMBi0eXrB3VzXhg_1755483098 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 383BE195608E; Mon, 18 Aug 2025 02:11:38 +0000 (UTC) Received: from localhost (unknown [10.72.112.210]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EE9D719560AD; Mon, 18 Aug 2025 02:11:36 +0000 (UTC) Date: Mon, 18 Aug 2025 10:11:32 +0800 From: Baoquan He To: "Uladzislau Rezki (Sony)" Cc: linux-mm@kvack.org, Andrew Morton , Vlastimil Babka , Michal Hocko , LKML Subject: Re: [PATCH 3/8] mm/vmalloc: Support non-blocking GFP flags in alloc_vmap_area() Message-ID: References: <20250807075810.358714-1-urezki@gmail.com> <20250807075810.358714-4-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: <20250807075810.358714-4-urezki@gmail.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 08/07/25 at 09:58am, 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. > > 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 6dbcdceecae1..81b6d3bde719 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; > > @@ -2026,7 +2027,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > if (unlikely(!vmap_initialized)) > return ERR_PTR(-EBUSY); > > - 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 error; > + } > > 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); > > +error: > kmem_cache_free(vmap_area_cachep, va); > return ERR_PTR(-EBUSY); > } > -- > 2.39.5 >