Date: Sat, 1 Oct 2005 23:15:32 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: net@FreeBSD.org Subject: Re: [REVIEW/TEST] polling(4) changes Message-ID: <20051001221058.G1493@epsplex.bde.org> In-Reply-To: <20050930124000.GA45345@cell.sick.ru> References: <20050930124000.GA45345@cell.sick.ru>
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On Fri, 30 Sep 2005, Gleb Smirnoff wrote: > The attached patch removes: > ... > - poll in trap feature. Sorry, we can't acquire mutexes in trap(). Anyone > used it, anyway? This is the most broken part of DEVICE_POLLING (which I consider to be mostly broken). Hopefully no one used it. Poll in trap even polled in debugger traps, so userland could invoke polling by debugging any program, and ether_poll() was reentered if it was debugged (in RELENG_4, there is no relevant locking so ether_poll() then just raced itself; in old versions of -current I think Giant locking allowed the same since Giant is recursive; in -current I think this causes deadlock since poll_mtx is not recursive). > The attached patch touches only em(4) and fxp(4). I will write patches for all > other drivers ASAP. But I don't have all the hardware, so if you are using polling(4) > and you run FreeBSD 6 or 7, please help me with testing. ATM only em(4) driver patch > is tested. While you are there, please fix the configuration so that DEVICE_POLLING is a normal option. It is very far from being a global option. Bruce
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