Date: Wed, 31 Jan 2001 00:59:23 +0100 From: Thomas Moestl <tmoestl@gmx.net> To: Matt Dillon <dillon@earth.backplane.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: removing setgid kmem from top, collecting per-device swap stats Message-ID: <20010131005923.A2199@crow.dom2ip.de> In-Reply-To: <200101302321.f0UNLcB95520@earth.backplane.com>; from dillon@earth.backplane.com on Tue, Jan 30, 2001 at 03:21:38PM -0800 References: <20010130224759.A1589@crow.dom2ip.de> <200101302321.f0UNLcB95520@earth.backplane.com>
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On Tue, Jan 30, 2001 at 03:21:38PM -0800, Matt Dillon wrote: > :vm.swapdev1.total (this is the one that is currently hard to get) > You can't move swapinfo into the kernel as a sysctl unless you > solve this problem. Traversing the radix tree is expensive enough > that the entire system will stall for a short period of time if you run > the loop in the kernel. Yes. I did not have that in mind. > The issue here is that swapinfo tries to break the useage down by > swap area, whereas the kernel has no real concept of swap areas > in the allocation map -- it just sees one big contiguous allocation > map. So the kernel does not track allocations on a per-swap-area > basis. My thought was the following: add a swapaccount vnode operation, and then do (in flushchainbuf): VOP_SWAPACCOUNT(nbp->b_vp, nbp); BUF_KERNPROC(nbp); BUF_STRATEGY(nbp); Now, I have to define the vop in vm_swap.c, where I can get the area index from the block number in a clean way and frob my counters. The same method could be used in swap_pager_putpages(). swap_pager_reserve() would need to construct a buf and act in a similar way as e.g. swap_pager_strategy(), only that the buffer is not flushed afterwards, only VOP_SWAPACCOUNT is called. Of course, this can be done much easier by just passing the block number to VOP_SWAPACCOUNT, and calling it for each blk returned by swp_pager_getswapspace() (it costs virtually nothing, so it should be OK). So, VOP_SWAPACCOUNT would become: VOP_SWAPACCOUNT(nbp->b_vp, nbp->b_blkno, nbp->bcount); Or did I get things wrong? - thomas To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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