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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> 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 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: F0896A0006 X-Stat-Signature: popx8phb7bjh44497qa3ouz516sgq4jd X-Rspam-User: X-HE-Tag: 1755483101-526007 X-HE-Meta: U2FsdGVkX1/6eJh8D7ZUO+SvoMKv62Dynl0eeKW7vYwBXv+hbXSDNM3n2Dk+LBBENZ3hmF7C44dkTIjAKQmBAjR/KspE3CR9/ep2fWFZbJtb4Lb/Iu3hvDDDEqbqTYDW1mCKPip8IWANPyWVyBcXXWtn5Rfamlr+t+nMuBIt48WXq/7wxwaknnAaFBZvMKeYgLk2qLME4YNR1R1+NmRsQiQD7e9CAH+z+oi9PFax+L3oYpbXM0W6H5waamNgpSOkjw+CQ1VA8E/8cC6CQZVrWLMf6wYHyz6hEcLE7tUjHerxJBxKZNGYhyLXxJ5y7Xq7WJ8u05Ubj9hAkSyAYmXagGJfYtTgrOIYCRhmFwTH/sdvt16uSiuieG11rKutcrqvi1ocav8YmZsQZeFxx3tv7it3uJwDpyCRcnTjdnrniMa9DnUPlE6RdNwS4LukGCoGwPRO37oquIxCHBn/T/Z1AQ6mGg+1uWbjaI82Nn/Co8ix/3aqgb5AoO7NlEKsMxTTsjIDCce58PIFhHgpaQ1i/ZdoXyUAYBT/f00zDA8A3m2w8BeTHoEE9lAPzpo9isppKDteKPexWtO4cQ2xRC3TFhLPCraMrXA3Hk81alQzSBhJXPIlFCv9vhEPLUZiQh2yRkBaOlqsrcDNDIbmSs56vMKSZ+bhx2EzL6kWyXa71Xr6DZVHQvz5f08thXWVF8MRWJTg4TY9a4QwFx9gh0IzeVO9bfMw04zfXpyLErOXEBNCD//liB9G2uhj3c3vX6Q75h7Q2AvpuAZyzKBEJyNx03z+h8H6tExZBohTJZ52QCAR3dVu/KW0HxpXDQjlga6rEHcctJBXpdNLkC25hrrG6ooJB9YYiRNFBC3oqdn7iuKX5PUfOb53RTxTt6omEr9JbW/fpuRYancp0rkGIxfyfwc2pYO5Q9JUKQjB0EqbNthnu9EVJdFYes1eaatm8fwYCzwl4oCfgr5iuOGaSg1 H9nAADlQ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 >