From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 526B9131742 for ; Thu, 21 Mar 2024 18:36:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711046218; cv=none; b=oeVBtrDLLT/jRQsjOWKwB92eg1ZWl2QvWRn5ErlLgKydqa8YR0VfREP4RT4cuoGxjm04gtHaIZcqu2bY6L0rWfREOOfpr2TsW2ekMUYMVH0LAXAtcoXUAPcxMJZMPy7kzOzCfIX0kFjYMq9qE3D0Wm0feoymfbCZPV+elRrfViw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711046218; c=relaxed/simple; bh=eUEa4rrGYlyZhAfRF+ds5sMG/T25zrE7GnOSK5h9F6Q=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=bApBStGQ2wGK33W8V6/EjVFuuqMJ96MgWriwjl/yQkaNX5JcUbLzn1ebbwu/YsbdgQCkxXOOSA+QMcEEf/R6+dkmLY0ydQz6qaZgMw1NqSkHgWevi5s2mPhtIFDXDCoklRUjCXQ3lfZVwEsK8j9EI42gQKiphSxbQ0zNoKse2BQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yosryahmed.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=gcjUmpdt; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--yosryahmed.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gcjUmpdt" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-dbf618042daso2039366276.0 for ; Thu, 21 Mar 2024 11:36:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1711046216; x=1711651016; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=bbCcL6OE4hGPljo6KgMnWz9lsSx4HXWFLCLqK+CpD5w=; b=gcjUmpdtt60sNeEEaUoO5jbxgfIyxKfnljDZEtqqVrjJ9ef+ictz9pmqTbfbWAKZ72 qNfKAVkDDeODcF5U1FUJ2ukO3K2046VnGEN/3gGa0qWo5ylKaIj4UNU8WOv+KEwW0T1A Z5uT+HLbmK/vpH+bStv9lCTAgi4c0EyGjQ1qhvIPm1gJjp8gWQ/7TBbUNZneAoO6wW76 B3TZdaIAWjnYyWltQcsDfFbIgpOO4NGPfcCAvlNjCgBEUBdVrPdTY2QWE/FjZtdWngbn kwZtS8ZXVTBzNsdwsDeyFojB0wNA+48SC+zrZnDAzrJ8IfQyfFgkhS2DmlB2F/ksHhHK vYJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711046216; x=1711651016; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=bbCcL6OE4hGPljo6KgMnWz9lsSx4HXWFLCLqK+CpD5w=; b=DkkC/h+ECbn3QUPyYPk/PxDG5YmSDOAxKE1aDTXuMigXIUIDmJtmgx03d44A6boVZb kteRawhMSI317lrE29FyfSIXjEejQoyBgAaVXaXK9xX0G7f8OmGhJYWiL7Gt3kHRD3ho wTELLgPcQrDMGHABxIIdheqkkBGyIcyb1gtaztuf0P0Ixy08asccVY12JU7xHnL/Z6IU HNloWG7pvrS9qMtdetVa4etzRAvBo0/tLko8A1oGgQIAwyiCowCebc4WJ5R1Rk57uIrP 4kVC8CCA8R/woji+do+lzx9D89Y4Ina8n1AV4cLchGt+wT5Fjbn8V46Qp89EPwA4/px/ 7LgQ== X-Forwarded-Encrypted: i=1; AJvYcCXOhMzkJbIiUs2YdqNyvFZaQ7Kx37hGbT8w3HncRiKpJyjLOJgGyBWa5ej3AUs4IcvoOsLBdY7Ji9CgNUpn3IovJtv2Ck6g X-Gm-Message-State: AOJu0YwAJp3lPX4GyKOY7xKY6Y7STJMm51MIJu1EVuiZi0h4uaADA6/5 p3rrxmxoYiBHvTEaGXR9zOkEZmdYyXcZboBtlGpB4LAuI+WDZR0dj5uAplZ+fUN2fBIQGiBKDLj CpUJSecjNjnexaZIWvw== X-Google-Smtp-Source: AGHT+IGVKM74DX/eJBUX2BxRcTwydQ0lZph+eL4O9Qy//R+b2lvRLwx760LaFZnBPco9gucSiCyzr9XwrWOfpihG X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:29b4]) (user=yosryahmed job=sendgmr) by 2002:a05:6902:2301:b0:dc7:865b:22c6 with SMTP id do1-20020a056902230100b00dc7865b22c6mr1248392ybb.8.1711046216453; Thu, 21 Mar 2024 11:36:56 -0700 (PDT) Date: Thu, 21 Mar 2024 18:36:54 +0000 In-Reply-To: <20240321182532.60000-1-hannes@cmpxchg.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240321182532.60000-1-hannes@cmpxchg.org> Message-ID: Subject: Re: [PATCH] mm: zswap: fix writeback shinker GFP_NOIO/GFP_NOFS recursion From: Yosry Ahmed To: Johannes Weiner Cc: Andrew Morton , Kent Overstreet , Chengming Zhou , Nhat Pham , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, Mar 21, 2024 at 02:25:32PM -0400, Johannes Weiner wrote: > Kent forwards this bug report of zswap re-entering the block layer > from an IO request allocation and locking up: > > [10264.128242] sysrq: Show Blocked State > [10264.128268] task:kworker/20:0H state:D stack:0 pid:143 tgid:143 ppid:2 flags:0x00004000 > [10264.128271] Workqueue: bcachefs_io btree_write_submit [bcachefs] > [10264.128295] Call Trace: > [10264.128295] > [10264.128297] __schedule+0x3e6/0x1520 > [10264.128303] schedule+0x32/0xd0 > [10264.128304] schedule_timeout+0x98/0x160 > [10264.128308] io_schedule_timeout+0x50/0x80 > [10264.128309] wait_for_completion_io_timeout+0x7f/0x180 > [10264.128310] submit_bio_wait+0x78/0xb0 > [10264.128313] swap_writepage_bdev_sync+0xf6/0x150 > [10264.128317] zswap_writeback_entry+0xf2/0x180 > [10264.128319] shrink_memcg_cb+0xe7/0x2f0 > [10264.128322] __list_lru_walk_one+0xb9/0x1d0 > [10264.128325] list_lru_walk_one+0x5d/0x90 > [10264.128326] zswap_shrinker_scan+0xc4/0x130 > [10264.128327] do_shrink_slab+0x13f/0x360 > [10264.128328] shrink_slab+0x28e/0x3c0 > [10264.128329] shrink_one+0x123/0x1b0 > [10264.128331] shrink_node+0x97e/0xbc0 > [10264.128332] do_try_to_free_pages+0xe7/0x5b0 > [10264.128333] try_to_free_pages+0xe1/0x200 > [10264.128334] __alloc_pages_slowpath.constprop.0+0x343/0xde0 > [10264.128337] __alloc_pages+0x32d/0x350 > [10264.128338] allocate_slab+0x400/0x460 > [10264.128339] ___slab_alloc+0x40d/0xa40 > [10264.128345] kmem_cache_alloc+0x2e7/0x330 > [10264.128348] mempool_alloc+0x86/0x1b0 > [10264.128349] bio_alloc_bioset+0x200/0x4f0 > [10264.128352] bio_alloc_clone+0x23/0x60 > [10264.128354] alloc_io+0x26/0xf0 [dm_mod 7e9e6b44df4927f93fb3e4b5c782767396f58382] > [10264.128361] dm_submit_bio+0xb8/0x580 [dm_mod 7e9e6b44df4927f93fb3e4b5c782767396f58382] > [10264.128366] __submit_bio+0xb0/0x170 > [10264.128367] submit_bio_noacct_nocheck+0x159/0x370 > [10264.128368] bch2_submit_wbio_replicas+0x21c/0x3a0 [bcachefs 85f1b9a7a824f272eff794653a06dde1a94439f2] > [10264.128391] btree_write_submit+0x1cf/0x220 [bcachefs 85f1b9a7a824f272eff794653a06dde1a94439f2] > [10264.128406] process_one_work+0x178/0x350 > [10264.128408] worker_thread+0x30f/0x450 > [10264.128409] kthread+0xe5/0x120 > > The zswap shrinker resumes the swap_writepage()s that were intercepted > by the zswap store. This will enter the block layer, and may even > enter the filesystem depending on the swap backing file. > > Make it respect GFP_NOIO and GFP_NOFS. > > Link: https://lore.kernel.org/linux-mm/rc4pk2r42oyvjo4dc62z6sovquyllq56i5cdgcaqbd7wy3hfzr@n4nbxido3fme/ > Reported-by: Kent Overstreet > Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure") > Cc: stable@vger.kernel.org [v6.8] > Signed-off-by: Johannes Weiner Acked-by: Yosry Ahmed Thanks for the quick fix. > --- > mm/zswap.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/mm/zswap.c b/mm/zswap.c > index b31c977f53e9..535c907345e0 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1303,6 +1303,14 @@ static unsigned long zswap_shrinker_count(struct shrinker *shrinker, > if (!zswap_shrinker_enabled || !mem_cgroup_zswap_writeback_enabled(memcg)) > return 0; > > + /* > + * The shrinker resumes swap writeback, which will enter block > + * and may enter fs. XXX: Harmonize with vmscan.c __GFP_FS > + * rules (may_enter_fs()), which apply on a per-folio basis. > + */ > + if (!gfp_has_io_fs(sc->gfp_mask)) > + return 0; > + > #ifdef CONFIG_MEMCG_KMEM > mem_cgroup_flush_stats(memcg); > nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT; > -- > 2.44.0 >