From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Andrew Morton <akpm@digeo.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] make vm_enough_memory more efficient
Date: Thu, 16 Jan 2003 07:22:33 -0800 [thread overview]
Message-ID: <75430000.1042730552@titus> (raw)
In-Reply-To: <20030116001447.07337e9e.akpm@digeo.com>
>> vm_enough_memory seems to call si_meminfo just to get the total
>> RAM, which seems far too expensive. This replaces the comment
>> saying "this is crap" with some code that's less crap.
>>
>> Not heavily tested (compiles and boots), but seems pretty obvious.
>
> Yup, obviously correct.
Cool.
> The really hurtful part of vm_enough_memory() is the call to
> get_page_cache_size(), which has to go over every CPU's local VM statistics
> in get_page_state().
>
> But I guess you're running with sysctl_overcommit_memory != 0.
Yup, I manually disable that because it's so expensive. I'll see if
I can make the default case cheaper as well.
M.
WARNING: multiple messages have this Message-ID (diff)
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Andrew Morton <akpm@digeo.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] make vm_enough_memory more efficient
Date: Thu, 16 Jan 2003 07:22:33 -0800 [thread overview]
Message-ID: <75430000.1042730552@titus> (raw)
In-Reply-To: <20030116001447.07337e9e.akpm@digeo.com>
>> vm_enough_memory seems to call si_meminfo just to get the total
>> RAM, which seems far too expensive. This replaces the comment
>> saying "this is crap" with some code that's less crap.
>>
>> Not heavily tested (compiles and boots), but seems pretty obvious.
>
> Yup, obviously correct.
Cool.
> The really hurtful part of vm_enough_memory() is the call to
> get_page_cache_size(), which has to go over every CPU's local VM statistics
> in get_page_state().
>
> But I guess you're running with sysctl_overcommit_memory != 0.
Yup, I manually disable that because it's so expensive. I'll see if
I can make the default case cheaper as well.
M.
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next prev parent reply other threads:[~2003-01-16 15:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-01-16 7:47 [PATCH] make vm_enough_memory more efficient Martin J. Bligh
2003-01-16 7:47 ` Martin J. Bligh
2003-01-16 8:14 ` Andrew Morton
2003-01-16 8:14 ` Andrew Morton
2003-01-16 15:22 ` Martin J. Bligh [this message]
2003-01-16 15:22 ` Martin J. Bligh
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