Date: Sun, 21 Sep 2014 23:04:01 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: btw@mail.ustc.edu.cn Cc: freebsd-hackers@freebsd.org Subject: Re: What's the difference between kmem_arena and kernel_arena? Message-ID: <20140921200401.GL2210@kib.kiev.ua> In-Reply-To: <1473289.768021411196850376.JavaMail.coremail@mailweb> References: <1473289.768021411196850376.JavaMail.coremail@mailweb>
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[-- Attachment #1 --] On Sat, Sep 20, 2014 at 03:07:30PM +0800, btw@mail.ustc.edu.cn wrote: > Hi All, > > There are two similar variables declared in vm/vm_kern.h, they are kernel_arena > and kmem_arena. Both of them are used in kmem_malloc(): > > rv = kmem_back((vmem == kmem_arena) ? kmem_object : kernel_object, > > I'm wondering what's the difference between them. Why both of them are needed? > I have done a lot of searching, but I still can not find an answer. Look at their usage. kmem_arena is used for the kernel malloc() and page-sized uma allocations. kernel_arena is used by miscellaneous other kernel needs, e.g. for kernel stacks of threads, as the backing for kva_alloc() etc. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUHy8wAAoJEJDCuSvBvK1Bt98P/234wuuVkI7vVi/ah/Zsa+lb 8DBhRZ+9gBOZ75NRXN+PUO3mpRJch3xl61+AVO0B7B5Uqr79bQOHEffZ4oTXRUjB t7+6Ib9xB6VoOLflq5cEvRHvgZtbdaRACiSI6fGvMFlqSJa8rSG9L4ygUAWFMPz1 1N00qTe2GxWJsHhedJF6GWe2DZDdZ9IRgGOiQqW+ptThcozM7D6Q2OReHyebdTei Ea2ZNLXRIVYPzQ9YhgOnkbWLGW2mNVbMTSByqdsEBgUS9PfPlgz0VHAvh0MBy/b9 E0YUBztXKLu3h+HuKx98aDe8lwAgVA7R9aVxLyAFEfaL1g1ToSYrNqLyKlWDa5CX jhlUak3dopusF7UzDFkjPgagdnrfQY1ae4sID5HziU6QqAbYVWVoGJqtN5EhMFQn qulrBAam11yCNpx+WPSb2EbAy9YZ4azmOMOa88zWHtNQ/LJ5GPu0DdpmKElHxQUX /lip40XrcX0224Dguy7+eRFqpgl9/0v3onI6xxP0TstMtNYbWhTeMcd1emiyS/lo 56QnXR+fe40/5KCDJjy1dgQOvBl2YidgbEshFdhm74ZuPAXJepMNe/KgQ1zCCB54 OkUxU20DgMJblE+of/6zlSA15BeORwd8g9x/4DsJ1MKInmtNCnoOuBrR+u0t9BpF qY4ud/lKdzYb3DFlmb7L =iwRC -----END PGP SIGNATURE-----
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