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Tue, 28 Sep 2021 12:15:41 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 3CFEB13A82; Tue, 28 Sep 2021 12:15:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id AaQgDW0HU2EhfwAAMHmgww (envelope-from ); Tue, 28 Sep 2021 12:15:41 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: cc92a241-2055-11ec-bc86-12813bfff9fa DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1632831341; h=from:from:reply-to: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=NUNiFLtAHLJUOzZDI5flM+QhBET7pJWEcR1eZ9Iuzto=; b=ML6ZW73YQdOWb6vihX4NED7+SKLZtlxQbN5DzB0E4UnV+JFPqB0EjK+NUviaxNP0aCeXlA niGLFJHf9jda3/CwauSg4fv/XYW9pIbAvcBTDgzPBusSatuOP9qd7UrjxjXVmgZa/kNGsY LFGzQWSM0Nq4E+jmkk65C/nvun9tPgA= Subject: Re: [PATCH v5 2/2] tools/xenstore: set open file descriptor limit for xenstored To: Ian Jackson Cc: xen-devel@lists.xenproject.org, Wei Liu References: <20210928091517.9761-1-jgross@suse.com> <20210928091517.9761-3-jgross@suse.com> <24915.1121.8356.288414@mariner.uk.xensource.com> From: Juergen Gross Message-ID: <0bd81ff3-a7ac-4000-4c0c-d7127b1c1985@suse.com> Date: Tue, 28 Sep 2021 14:15:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <24915.1121.8356.288414@mariner.uk.xensource.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="d0wtOka4OxLM2Z4Gskn4hq5a1mmazPunv" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --d0wtOka4OxLM2Z4Gskn4hq5a1mmazPunv Content-Type: multipart/mixed; boundary="JkvvaZn0wjfzVLkfML8Y2dXLPDLdgBca1"; protected-headers="v1" From: Juergen Gross To: Ian Jackson Cc: xen-devel@lists.xenproject.org, Wei Liu Message-ID: <0bd81ff3-a7ac-4000-4c0c-d7127b1c1985@suse.com> Subject: Re: [PATCH v5 2/2] tools/xenstore: set open file descriptor limit for xenstored References: <20210928091517.9761-1-jgross@suse.com> <20210928091517.9761-3-jgross@suse.com> <24915.1121.8356.288414@mariner.uk.xensource.com> In-Reply-To: <24915.1121.8356.288414@mariner.uk.xensource.com> --JkvvaZn0wjfzVLkfML8Y2dXLPDLdgBca1 Content-Type: multipart/mixed; boundary="------------7AA3DD2ABEF0A7F217775343" Content-Language: en-US This is a multi-part message in MIME format. --------------7AA3DD2ABEF0A7F217775343 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 28.09.21 14:02, Ian Jackson wrote: > Juergen Gross writes ("[PATCH v5 2/2] tools/xenstore: set open file des= criptor limit for xenstored"): >> Add a configuration item for the maximum number of open file >> descriptors xenstored should be allowed to have. >> >> The default should be "unlimited" in order not to restrict xenstored >> in the number of domains it can support, but unfortunately the kernel >> is normally limiting the maximum value via /proc/sys/fs/nr_open [1], >> [2]. So check that file to exist and if it does, limit the maximum >> value to the one specified by /proc/sys/fs/nr_open. >> >> As an aid for the admin configuring the value add a comment specifying= >> the common needs of xenstored for the different domain types. > ... >> echo -n Starting $XENSTORED... >> @@ -70,6 +89,7 @@ test -f @CONFIG_DIR@/@CONFIG_LEAF_DIR@/xencommons &&= . @CONFIG_DIR@/@CONFIG_LEAF >> systemd-notify --booted 2>/dev/null || timeout_xenstore $XENSTORED = || exit 1 >> XS_PID=3D`cat @XEN_RUN_DIR@/xenstored.pid` >> echo $XS_OOM_SCORE >/proc/$XS_PID/oom_score_adj >> + prlimit --pid $XS_PID --nofile=3D$XENSTORED_MAX_OPEN_FDS >=20 > Thanks for this. I have one comment/question, which I regret making > rather late: >=20 > I am uncomfortable with the use of prlimit here, because identifying > processes by pid is typically inherently not 100% reliable. >=20 > AIUI you are using it here because perhaps otherwise you would have to > mess about with both systemd and non-systemd approaches. But in fact > this script "launch-xenstore" is simply a parent of xenstore. It is > run either by systemd or from the init script, and it runs $XENSTORED > directly (so not via systemd or another process supervisor). >=20 > fd limits are inherited, so I think you can use ulimit rather than > prlimit ? >=20 > If you use ulimit I think you must set the hard and soft limits, > which requires two calls. >=20 > If you can't use ulimit then we should try to make some argument that > the prlimit can't target the wrong process eg due to a > misconfiguration or stale pid file or soemthing. I think I see a way > that such an argument could be construted but it would be better just > to use ulimit. Hmm, maybe I should just use: prlimit --nofile=3D$XENSTORED_MAX_OPEN_FDS \ $XENSTORED --pid-file @XEN_RUN_DIR@/xenstored.pid $XENSTORED_ARGS Juergen --------------7AA3DD2ABEF0A7F217775343 Content-Type: application/pgp-keys; name="OpenPGP_0xB0DE9DD628BF132F.asc" Content-Transfer-Encoding: quoted-printable Content-Description: OpenPGP public key Content-Disposition: attachment; filename="OpenPGP_0xB0DE9DD628BF132F.asc" -----BEGIN PGP PUBLIC KEY BLOCK----- xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOBy= cWx w3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJvedYm8O= f8Z d621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJNwQpd369y= 9bf IhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvxXP3FAp2pkW0xq= G7/ 377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEBAAHNHEp1ZXJnZW4gR= 3Jv c3MgPGpnQHBmdXBmLm5ldD7CwHkEEwECACMFAlOMcBYCGwMHCwkIBwMCAQYVCAIJCgsEFgIDA= QIe AQIXgAAKCRCw3p3WKL8TL0KdB/93FcIZ3GCNwFU0u3EjNbNjmXBKDY4FUGNQH2lvWAUy+dnyT= hpw dtF/jQ6j9RwE8VP0+NXcYpGJDWlNb9/JmYqLiX2Q3TyevpB0CA3dbBQp0OW0fgCetToGIQrg0= MbD 1C/sEOv8Mr4NAfbauXjZlvTj30H2jO0u+6WGM6nHwbh2l5O8ZiHkH32iaSTfN7Eu5RnNVUJbv= oPH Z8SlM4KWm8rG+lIkGurqqu5gu8q8ZMKdsdGC4bBxdQKDKHEFExLJK/nRPFmAuGlId1E3fe10v= 5QL +qHI3EIPtyfE7i9Hz6rVwi7lWKgh7pe0ZvatAudZ+JNIlBKptb64FaiIOAWDCx1SzR9KdWVyZ= 2Vu IEdyb3NzIDxqZ3Jvc3NAc3VzZS5jb20+wsB5BBMBAgAjBQJTjHCvAhsDBwsJCAcDAgEGFQgCC= QoL BBYCAwECHgECF4AACgkQsN6d1ii/Ey/HmQf/RtI7kv5A2PS4RF7HoZhPVPogNVbC4YA6lW7Dr= Wf0 teC0RR3MzXfy6pJ+7KLgkqMlrAbN/8Dvjoz78X+5vhH/rDLa9BuZQlhFmvcGtCF8eR0T1v0nC= /nu AFVGy+67q2DH8As3KPu0344TBDpAvr2uYM4tSqxK4DURx5INz4ZZ0WNFHcqsfvlGJALDeE0Lh= ITT d9jLzdDad1pQSToCnLl6SBJZjDOX9QQcyUigZFtCXFst4dlsvddrxyqT1f17+2cFSdu7+ynLm= XBK 7abQ3rwJY8SbRO2iRulogc5vr/RLMMlscDAiDkaFQWLoqHHOdfO9rURssHNN8WkMnQfvUewRz= 80h SnVlcmdlbiBHcm9zcyA8amdyb3NzQG5vdmVsbC5jb20+wsB5BBMBAgAjBQJTjHDXAhsDBwsJC= AcD AgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey8PUQf/ehmgCI9jB9hlgexLvgOtf7PJn= FOX gMLdBQgBlVPO3/D9R8LtF9DBAFPNhlrsfIG/SqICoRCqUcJ96Pn3P7UUinFG/I0ECGF4EvTE1= jnD kfJZr6jrbjgyoZHiw/4BNwSTL9rWASyLgqlA8u1mf+c2yUwcGhgkRAd1gOwungxcwzwqgljf0= N51 N5JfVRHRtyfwq/ge+YEkDGcTU6Y0sPOuj4Dyfm8fJzdfHNQsWq3PnczLVELStJNdapwPOoE+l= otu fe3AM2vAEYJ9rTz3Cki4JFUsgLkHFqGZarrPGi1eyQcXeluldO3m91NK/1xMI3/+8jbO0tsn1= tqS EUGIJi7ox80eSnVlcmdlbiBHcm9zcyA8amdyb3NzQHN1c2UuZGU+wsB5BBMBAgAjBQJTjHDrA= hsD BwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey+LhQf9GL45eU5vOowA2u5N3= g3O ZUEBmDHVVbqMtzwlmNC4k9Kx39r5s2vcFl4tXqW7g9/ViXYuiDXb0RfUpZiIUW89siKrkzmQ5= dM7 wRqzgJpJwK8Bn2MIxAKArekWpiCKvBOB/Cc+3EXE78XdlxLyOi/NrmSGRIov0karw2RzMNOu5= D+j LRZQd1Sv27AR+IP3I8U4aqnhLpwhK7MEy9oCILlgZ1QZe49kpcumcZKORmzBTNh30FVKK1Evm= V2x AKDoaEOgQB4iFQLhJCdP1I5aSgM5IVFdn7v5YgEYuJYx37IoN1EblHI//x/e2AaIHpzK5h88N= Eaw QsaNRpNSrcfbFmAg987ATQRTjHAWAQgAyzH6AOODMBjgfWE9VeCgsrwH3exNAU32gLq2xvjpW= nHI s98ndPUDpnoxWQugJ6MpMncr0xSwFmHEgnSEjK/PAjppgmyc57BwKII3sV4on+gDVFJR6Y8ZR= wgn BC5mVM6JjQ5xDk8WRXljExRfUX9pNhdE5eBOZJrDRoLUmmjDtKzWaDhIg/+1Hzz93X4fCQkNV= bVF LELU9bMaLPBG/x5q4iYZ2k2ex6d47YE1ZFdMm6YBYMOljGkZKwYde5ldM9mo45mmwe0icXKLk= pEd IXKTZeKDO+Hdv1aqFuAcccTg9RXDQjmwhC3yEmrmcfl0+rPghO0Iv3OOImwTEe4co3c1mwARA= QAB wsBfBBgBAgAJBQJTjHAWAhsMAAoJELDendYovxMvQ/gH/1ha96vm4P/L+bQpJwrZ/dneZcmEw= Tbe 8YFsw2V/Buv6Z4Mysln3nQK5ZadD534CF7TDVft7fC4tU4PONxF5D+/tvgkPfDAfF77zy2AH1= vJz Q1fOU8lYFpZXTXIHb+559UqvIB8AdgR3SAJGHHt4RKA0F7f5ipYBBrC6cyXJyyoprT10EMvU8= VGi wXvTyJz3fjoYsdFzpWPlJEBRMedCot60g5dmbdrZ5DWClAr0yau47zpWj3enf1tLWaqcsuylW= svi uGjKGw7KHQd3bxALOknAp4dN3QwBYCKuZ7AddY9yjynVaD5X7nF9nO5BjR/i1DG86lem3iBDX= zXs ZDn8R38=3D =3D2wuH -----END PGP PUBLIC KEY BLOCK----- --------------7AA3DD2ABEF0A7F217775343-- --JkvvaZn0wjfzVLkfML8Y2dXLPDLdgBca1-- --d0wtOka4OxLM2Z4Gskn4hq5a1mmazPunv Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsB5BAABCAAjFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAmFTB2wFAwAAAAAACgkQsN6d1ii/Ey82 QQf/Ux//Nw4xu2jJNrGCIvY5KKLz1vsVwXgxJf3lhNt3idaxHf2eJYVqkCzFlKw1J5pbaYon4jeK XhrvNOK9Yktz14BhDMXk+bCxEDAZLxEV0mtebuVb8zwEZJ+51d0t5zr5Fj6DdiLVSlSeFMiozre3 7coJmCj/u3A5Ay9QWK2336GyzSaQHYhOA3+Kfb+EyvCeyEmhD8KrAcm85a/czK93z3ywrp1f5kTM FqTT7Bm0+CIk9qC+l9W118xnkKw6KsRNOOXRvzHu1xJmT8RKT2u0kkaS7uQfgaLHmgquOu8tD6ia VWhv4xT4AfPvRX6N5Qj+nv4F8fPGHo4azQ8lLdZDaQ== =DtiI -----END PGP SIGNATURE----- --d0wtOka4OxLM2Z4Gskn4hq5a1mmazPunv--