Date: Thu, 7 Jan 2016 17:37:03 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Chagin Dmitry <dchagin@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r275121 - in head/sys: compat/linux compat/svr4 fs/procfs kern sys Message-ID: <20160107153703.GV3625@kib.kiev.ua> In-Reply-To: <20160107133953.GA62554@chd.heemeyer.club> References: <201411261410.sAQEA0JO071065@svn.freebsd.org> <20160107133953.GA62554@chd.heemeyer.club>
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On Thu, Jan 07, 2016 at 04:39:53PM +0300, Chagin Dmitry wrote: > On Wed, Nov 26, 2014 at 02:10:00PM +0000, Konstantin Belousov wrote: > > Author: kib > > Date: Wed Nov 26 14:10:00 2014 > > New Revision: 275121 > > URL: https://svnweb.freebsd.org/changeset/base/275121 > > > > Log: > > The process spin lock currently has the following distinct uses: > > > > - Threads lifetime cycle, in particular, counting of the threads in > > the process, and interlocking with process mutex and thread lock. > > The main reason of this is that turnstile locks are after thread > > locks, so you e.g. cannot unlock blockable mutex (think process > > mutex) while owning thread lock. > > > > - Virtual and profiling itimers, since the timers activation is done > > from the clock interrupt context. Replace the p_slock by p_itimmtx > > and PROC_ITIMLOCK(). > > > > - Profiling code (profil(2)), for similar reason. Replace the p_slock > > by p_profmtx and PROC_PROFLOCK(). > > > > - Resource usage accounting. Need for the spinlock there is subtle, > > my understanding is that spinlock blocks context switching for the > > current thread, which prevents td_runtime and similar fields from > > changing (updates are done at the mi_switch()). Replace the p_slock > > by p_statmtx and PROC_STATLOCK(). > > > > The split is done mostly for code clarity, and should not affect > > scalability. > > > > Tested by: pho > > Sponsored by: The FreeBSD Foundation > > MFC after: 1 week > hi, any chance to merge it? I do not want to merge the split, for many reasons. I suppose the merge conflicts due to the replace of PROC_SLOCK() by PROC_*LOCK() are what you are looking after, am I right ? What could be done, is to merge the syntax changes from the patch. I mean, provide the PROC_*LOCK() macros and merge all changes to use new macros, but internal implementation would still lock the same proc spinlock.
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