Date: Fri, 9 May 2003 20:18:31 -0400 (EDT) From: Jeff Roberson <jroberson@chesapeake.net> To: John Baldwin <jhb@freebsd.org> Cc: arch@freebsd.org Subject: Re: [Bikeshed] sigacts locking Message-ID: <20030509201646.Q99131-100000@mail.chesapeake.net> In-Reply-To: <XFMail.20030509175046.jhb@FreeBSD.org>
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On Fri, 9 May 2003, John Baldwin wrote: > As part of the locking for the proc structure, I needed to lock > the procsig and sigacts stuctures so that kill(), killpg(), > sigaction() and a few other system calls can be pulled out from > under Giant. After talking with Peter some, I decided to > pull the sigacts structure out of the u-area and merge it with > the procsig structure under the sigacts name. I then added a > mutex to each sigacts and added locking where appropriate. With > this change, the aforementioned system calls are now MP safe > along with sendsig(), *signal(), cursig(), etc. The patch for > all this is at http://www.FreeBSD.org/~jhb/patches/sigacts.patch > I would appreciate comments, review, etc. that people may have. > If all goes well I hope to get this into 5.1. Thanks. > I'm all for this, but I have a few concerns. Right now the UAREA is mostly taken up by sigacts. Without it the page is quite empty. This means that we'll be allocating more storage elsewhere while leaving this for nothing. Have you given any thought to removing the other bits from uarea, or allocating uarea using a zone instead of a whole page? Alternatively, you could disable paging for the uarea and leave sigacts in it. I just hate to s ee the wasted space. Cheers, Jeff
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