From: Simon Jeons <simon.jeons@gmail.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org,
Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
Nick Piggin <npiggin@kernel.dk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: PAGE_CACHE_SIZE vs. PAGE_SIZE
Date: Tue, 19 Feb 2013 18:32:36 +0800 [thread overview]
Message-ID: <512354C4.2040705@gmail.com> (raw)
In-Reply-To: <20130118155724.GA8507@otc-wbsnb-06>
On 01/18/2013 11:57 PM, Kirill A. Shutemov wrote:
> Hi,
>
> PAGE_CACHE_* macros were introduced long time ago in hope to implement
> page cache with larger chunks than one page in future.
>
> In fact it was never done.
>
> Some code paths assume PAGE_CACHE_SIZE <= PAGE_SIZE. E.g. we use
> zero_user_segments() to clear stale parts of page on cache filling, but
> the function is implemented only for individual small page.
>
> It's unlikely that global switch to PAGE_CACHE_SIZE > PAGE_SIZE will never
> happen since it will affect to much code at once.
>
> I think support of larger chunks in page cache can be in implemented in
> some form of THP with per-fs enabling.
IIRC, you try to implement THP support page cache, then PAGE_CACHE_SIZE
maybe don't need any more.
>
> Is it time to get rid of PAGE_CACHE_* macros?
> I can prepare patchset if it's okay.
>
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WARNING: multiple messages have this Message-ID (diff)
From: Simon Jeons <simon.jeons@gmail.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org,
Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
Nick Piggin <npiggin@kernel.dk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: PAGE_CACHE_SIZE vs. PAGE_SIZE
Date: Tue, 19 Feb 2013 18:32:36 +0800 [thread overview]
Message-ID: <512354C4.2040705@gmail.com> (raw)
In-Reply-To: <20130118155724.GA8507@otc-wbsnb-06>
On 01/18/2013 11:57 PM, Kirill A. Shutemov wrote:
> Hi,
>
> PAGE_CACHE_* macros were introduced long time ago in hope to implement
> page cache with larger chunks than one page in future.
>
> In fact it was never done.
>
> Some code paths assume PAGE_CACHE_SIZE <= PAGE_SIZE. E.g. we use
> zero_user_segments() to clear stale parts of page on cache filling, but
> the function is implemented only for individual small page.
>
> It's unlikely that global switch to PAGE_CACHE_SIZE > PAGE_SIZE will never
> happen since it will affect to much code at once.
>
> I think support of larger chunks in page cache can be in implemented in
> some form of THP with per-fs enabling.
IIRC, you try to implement THP support page cache, then PAGE_CACHE_SIZE
maybe don't need any more.
>
> Is it time to get rid of PAGE_CACHE_* macros?
> I can prepare patchset if it's okay.
>
next prev parent reply other threads:[~2013-02-19 10:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-18 15:57 PAGE_CACHE_SIZE vs. PAGE_SIZE Kirill A. Shutemov
2013-01-31 22:40 ` Andrew Morton
2013-01-31 22:40 ` Andrew Morton
2013-02-19 16:12 ` Michel Lespinasse
2013-02-19 16:12 ` Michel Lespinasse
2013-02-19 10:32 ` Simon Jeons [this message]
2013-02-19 10:32 ` Simon Jeons
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