From: Ian Jackson <ian.jackson@citrix.com>
To: Anthony PERARD <anthony.perard@citrix.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Wei Liu <wl@xen.org>
Subject: Re: [Xen-devel] [PATCH v2 4/9] libxl: Add optimisation to ev_lock
Date: Tue, 17 Sep 2019 16:49:03 +0100 [thread overview]
Message-ID: <23937.111.256134.571464@mariner.uk.xensource.com> (raw)
In-Reply-To: <20190614103801.22619-5-anthony.perard@citrix.com>
Anthony PERARD writes ("[PATCH v2 4/9] libxl: Add optimisation to ev_lock"):
> It will often be the case that the lock is free to grab. So we first
> try to grab it before we have to fork. Even though in this case the
> locks are grabbed in the wrong order in the lock hierarchy (ev_lock
> should be outside of CTX_LOCK), it is fine to try without blocking. If
> that failed, we will release CTX_LOCK and try to grab both lock again
> in the right order.
>
> That optimisation is only enabled in releases (debug=n) so the more
> complicated code with fork is actually exercised.
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
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next prev parent reply other threads:[~2019-09-17 15:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 10:37 [Xen-devel] [PATCH v2 0/9] libxl: New slow lock + fix libxl_cdrom_insert with QEMU depriv Anthony PERARD
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 1/9] libxl_internal: Remove lost comment Anthony PERARD
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 2/9] libxl: Pointer on usage of libxl__domain_userdata_lock Anthony PERARD
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 3/9] libxl_internal: Introduce libxl__ev_lock for devices hotplug via QMP Anthony PERARD
2019-09-17 15:44 ` Ian Jackson
2019-09-18 9:59 ` Anthony PERARD
2019-09-18 10:39 ` Ian Jackson
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 4/9] libxl: Add optimisation to ev_lock Anthony PERARD
2019-09-17 15:49 ` Ian Jackson [this message]
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 5/9] libxl_disk: Reorganise libxl_cdrom_insert Anthony PERARD
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 6/9] libxl_disk: Cut libxl_cdrom_insert into steps Anthony PERARD
2019-09-17 16:20 ` Ian Jackson
2019-06-14 10:37 ` [Xen-devel] [PATCH v2 7/9] libxl_disk: Implement missing timeout for libxl_cdrom_insert Anthony PERARD
2019-06-14 10:38 ` [Xen-devel] [PATCH v2 8/9] libxl: Move qmp_parameters_* prototypes to libxl_internal.h Anthony PERARD
2019-06-14 10:38 ` [Xen-devel] [PATCH v2 9/9] libxl_disk: Use ev_qmp in libxl_cdrom_insert Anthony PERARD
2019-09-17 16:22 ` [Xen-devel] [PATCH v2 0/9] libxl: New slow lock + fix libxl_cdrom_insert with QEMU depriv Ian Jackson
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