Date: Mon, 10 Jul 2017 15:40:46 +0900 From: Tomoaki AOKI <junchoon@dec.sakura.ne.jp> To: freebsd-current@freebsd.org Cc: otacilio.neto@bsd.com.br Subject: Re: type of vm.stats.vm.v_vnodepgsin vm.stats.vm.v_swappgsin, vm.stats.vm.v_vnodepgsout vm.stats.vm.v_swappgsout on AMD64 r320730 Message-ID: <20170710154046.58c3d7b14a227a20bea3e55b@dec.sakura.ne.jp> In-Reply-To: <1c37db96-7cd2-91c9-011c-967a32a97f05@bsd.com.br> References: <1c37db96-7cd2-91c9-011c-967a32a97f05@bsd.com.br>
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Hi. Members v_swappgsin and v_vnodepgsin are declared on sys/sys/vmmeter.h as u_int on stable/11@r320798 [1] counter_u64_t on head@r320861 [2] respectively. Diggin in further, on head@r320861, counter_u64_t is typedef'ed as uint64_t * at line 32 of sys/sys/counter.h [3] like below. typedef uint64_t *counter_u64_t; So they're "pointers" on head, while "values" on stable/11. So, as you're on head, it seems you're casting "pointers (addresses)" to uint64_t "value". It could be huge and non-expected values. Your code would work as expected on stable/11. [1] https://svnweb.freebsd.org/base/stable/11/sys/sys/vmmeter.h?annotate=320610 [2] https://svnweb.freebsd.org/base/head/sys/sys/vmmeter.h?annotate=317061 [3] https://svnweb.freebsd.org/base/head/sys/sys/counter.h?annotate=309745 On Sun, 9 Jul 2017 23:15:18 -0300 Otac〓lio <otacilio.neto@bsd.com.br> wrote: > Dears > > I'm the maintainer of xosview and I'm debugging rather weird behavior > from it in the latest FreeBSD 12 revisions (12.0-CURRENT #0 r320730 > AMD64) . The problem is occurring on the lines responsible for > collecting statistics about paging. These lines follow: > > If (pageinfo) { > Pageinfo [0] = (uint64_t) vm.v_vnodepgsin + (uint64_t) vm.v_swappgsin; > Pageinfo [1] = (uint64_t) vm.v_vnodepgsout + (uint64_t) vm.v_swappgsout; > } > > This code works on FreeBSD 11 and until a short time ago it works at 12. > But now it returns extremely large values 〓〓when interpreted as 64-bit > values. A debugging has shown that for this sysctl call the following > values 〓〓are returned in the terminal: > sysctl vm.stats.vm.v_vnodepgsin vm.stats.vm.v_swappgsin > vm.stats.vm.v_vnodepgsout vm.stats.vm.v_swappgsout > Vm.stats.vm.v_vnodepgsin: 47432 > Vm.stats.vm.v_swappgsin: 0 > Vm.stats.vm.v_vnodepgsout: 19 > Vm.stats.vm.v_swappgsout: 0 > > While the code returns things like: > > Pageinf [0] = 34359785800; Pageinfo [1] = 140733193388051 > Pageinf [0] = 34359785800; Pageinfo [1] = 2678138638516092947 > > After some tests I found that if I change the code to use a typecast to > (uint32_t) then Xosview works correctly.: > If (pageinfo) { > Pageinfo [0] = (uint32_t) ((uint64_t) vm.v_vnodepgsin + (uint64_t) > vm.v_swappgsin); > Pageinfo [1] = (uint32_t) ((uint64_t) vm.v_vnodepgsout + (uint64_t) > vm.v_swappgsout); > } > > For me, it seems that some code in the kernel is storing values 〓〓as 32 > bits where it should be 64 bits. Is this behavior correct? > > []'s > > -Otac〓lio > _______________________________________________ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > > -- Tomoaki AOKI <junchoon@dec.sakura.ne.jp>
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