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| From | Linus Torvalds <torvalds@linux-foundation.org> |
| Newsgroups | linux.kernel |
| Subject | Re: get_vmalloc_info() and /proc/meminfo insanely expensive |
| Date | Fri, 14 Aug 2015 01:00:02 +0200 |
| Message-ID | <pX9DA-q0-15@gated-at.bofh.it> (permalink) |
| References | <pWRnk-7WT-1@gated-at.bofh.it> <pWS01-tB-7@gated-at.bofh.it> <pWTIu-2Kb-1@gated-at.bofh.it> <pX5zY-32e-13@gated-at.bofh.it> <pX8eu-6ZO-17@gated-at.bofh.it> |
| X-Original-To | Tony Luck <tony.luck@gmail.com> |
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| X-Original-Cc | Andrew Morton <akpm@linux-foundation.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Al Viro <viro@zeniv.linux.org.uk>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> |
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On Thu, Aug 13, 2015 at 2:15 PM, Tony Luck <tony.luck@gmail.com> wrote:
>
> could you at least care enough to write that as
>
> if (time_after(now, last + HZ)) {
Absolutely not. That would be wrong.
"time_after()" covers half the "unsigned long" space (very much on
purpose). We want the cached case to trigger _only_ for the much
tighter case of exactly 1000 jiffies.
Linus
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get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 05:30 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Andrew Morton <akpm@linux-foundation.org> - 2015-08-13 06:10 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 08:00 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2015-08-13 09:50 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 19:00 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 20:40 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 21:00 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive David Rientjes <rientjes@google.com> - 2015-08-13 22:00 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-13 22:10 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Tony Luck <tony.luck@gmail.com> - 2015-08-13 23:30 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-14 01:00 +0200
Re: get_vmalloc_info() and /proc/meminfo insanely expensive Andrew Morton <akpm@linux-foundation.org> - 2015-08-13 22:30 +0200
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