From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH rdma-next v1 4/6] IB/core: Fix use workqueue without WQ_MEM_RECLAIM Date: Mon, 16 Oct 2017 21:32:17 +0300 Message-ID: <20171016183217.GL2106@mtr-leonro.local> References: <20171016054517.30643-1-leon@kernel.org> <20171016054517.30643-5-leon@kernel.org> <4f08314e-fd5d-c108-438a-d9e83821e4b3@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="AeHkbrJcO8giN/MO" Return-path: Content-Disposition: inline In-Reply-To: <4f08314e-fd5d-c108-438a-d9e83821e4b3-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jonathan Toppins Cc: Doug Ledford , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Parav Pandit List-Id: linux-rdma@vger.kernel.org --AeHkbrJcO8giN/MO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Oct 16, 2017 at 01:24:12PM -0400, Jonathan Toppins wrote: > On 10/16/2017 01:45 AM, Leon Romanovsky wrote: > > From: Parav Pandit > > > > The IB/core provides address resolution service and invokes callback > > handler when address resolve request completes of requester in worker > > thread context. > > > > Such caller might allocate or free memory in callback handler > > depending on the completion status to make further progress or to > > terminate a connection. Most ULPs resolve route which involves > > allocating route entry and path record elements in callback event handler. > > > > It has been noticed that WQ_MEM_RECLAIM flag should not be used for > > workers that tend to allocate memory in this [1] thread discussion. > > > > In order to mitigate this situation, WQ_MEM_RECLAIM flag was dropped for > > other such WQs in this [2] patch. > > > > Similar problem might arise with address resolution path, though its not > > yet noticed. The ib_addr workqueue is not memory reclaim path due to its > > nature of invoking callback that might allocate memory or don't free any > > memory under memory pressure. > > > > [1] https://www.spinics.net/lists/linux-rdma/msg53239.html > > [2] https://www.spinics.net/lists/linux-rdma/msg53416.html > > > > Fixes: f54816261c2b ("IB/addr: Remove deprecated create_singlethread_workqueue") > > Fixes: 5fff41e1f89d ("IB/core: Fix race condition in resolving IP to MAC") > > Signed-off-by: Parav Pandit > > Reviewed-by: Daniel Jurgens > > Signed-off-by: Leon Romanovsky > > This looks like a -stable patch candidate. Once accepted this should > probably be queued for v4.9+. I don't have any strong opinion about that. Thanks > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --AeHkbrJcO8giN/MO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAlnk+zEACgkQ5GN7iDZy WKfiFBAAlkgp/DunBrksPkd3CBugAdvoVjJjUULpXjaPtC+sTcRUzBJ77iKzLess JpxNPiQ2+5Oyxo2SvQWdu2c1nEl6nU2wDbW5iY+YAA4ZRqysD6d6iuUL22R0w+2w RNZSYtduhLyfE8vwx6kSgUWl/XfY8jNNym9xJ6oISgkrRubnZtyiJKHnj+iI2OZK 1xXCGfH8AN3deXpI4SAC/Nls9tMkC3h9IlVYYBdnyh+ZnfiVdFYGJY8YzjlFUP8b kpveo/P20AswtqvW4yV2Rv7yHd3ehYkVOHg7xHkPvfBFY1Cg9w5NYB/avztpAI2g ETUHPLIfgvGo9eTlROulKUGG+YbrIW7HjjXmzKE+A2rUwUcMxnnUB5UCgky4JsgA SS8x+giTuAPFr0MYw9be8oiOlvzv67BkIIVvKbMMR4KZ0ihm2QUIHQZFJ9gilJ4V lAcdgvAOMSKUIus/Tz66Dn0zSTR2jlk9Sex961fufhZOMpN2Po8CKLmywZWTtgdD nMcFhPTlzZkZgXptYh8YNkd0yjbhFhRyL0jqwqTcBpE8pMTokWrQZKVCRoGM2K5J Jod0PEgioHJal1VuNpBL8DxCm3OkiNxzRPaF/vEVmowU/PrVLBRe+7/TKZSFQWKO dST3IYQiAChJnhLgOhZV3oe7myDNdjbiH3s9tPbIrvdko+KuW+o= =R96l -----END PGP SIGNATURE----- --AeHkbrJcO8giN/MO-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html