From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org
Subject: Re: [RFC 00/11] Remove 'order' argument from many mm functions
Date: Thu, 9 May 2019 14:07:55 +0300 [thread overview]
Message-ID: <20190509110755.v4dzyophpaoinqhr@box> (raw)
In-Reply-To: <20190507040609.21746-1-willy@infradead.org>
On Mon, May 06, 2019 at 09:05:58PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> It's possible to save a few hundred bytes from the kernel text by moving
> the 'order' argument into the GFP flags. I had the idea while I was
> playing with THP pagecache (notably, I didn't want to add an 'order'
> parameter to pagecache_get_page())
>
> What I got for a -tiny config for page_alloc.o (with a tinyconfig,
> x86-32) after each step:
>
> text data bss dec hex filename
> 21462 349 44 21855 555f 1.o
> 21447 349 44 21840 5550 2.o
> 21415 349 44 21808 5530 3.o
> 21399 349 44 21792 5520 4.o
> 21399 349 44 21792 5520 5.o
> 21367 349 44 21760 5500 6.o
> 21303 349 44 21696 54c0 7.o
> 21303 349 44 21696 54c0 8.o
> 21303 349 44 21696 54c0 9.o
> 21303 349 44 21696 54c0 A.o
> 21303 349 44 21696 54c0 B.o
>
> I assure you that the callers all shrink as well. vmscan.o also
> shrinks, but I didn't keep detailed records.
>
> Anyway, this is just a quick POC due to me being on an aeroplane for
> most of today. Maybe we don't want to spend five GFP bits on this.
> Some bits of this could be pulled out and applied even if we don't want
> to go for the main objective. eg rmqueue_pcplist() doesn't use its
> gfp_flags argument.
I like the idea. But I'm somewhat worried about running out of bits in
gfp_t. Is there anything preventing us to bump gfp_t to u64 in the future?
next prev parent reply other threads:[~2019-05-14 13:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 4:05 Matthew Wilcox
2019-05-07 4:05 ` [PATCH 01/11] fix function alignment Matthew Wilcox
2019-05-09 10:55 ` Kirill A. Shutemov
2019-05-07 4:06 ` [PATCH 02/11] mm: Pass order to __alloc_pages_nodemask in GFP flags Matthew Wilcox
2019-05-09 1:50 ` Ira Weiny
2019-05-09 13:58 ` Matthew Wilcox
2019-05-09 16:22 ` Weiny, Ira
2019-05-09 10:59 ` Kirill A. Shutemov
2019-05-07 4:06 ` [PATCH 03/11] mm: Pass order to __get_free_pages() " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 04/11] mm: Pass order to prep_new_page " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 05/11] mm: Remove gfp_flags argument from rmqueue_pcplist Matthew Wilcox
2019-05-07 4:06 ` [PATCH 06/11] mm: Pass order to rmqueue in GFP flags Matthew Wilcox
2019-05-07 4:06 ` [PATCH 07/11] mm: Pass order to get_page_from_freelist " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 08/11] mm: Pass order to __alloc_pages_cpuset_fallback " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 09/11] mm: Pass order to prepare_alloc_pages " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 10/11] mm: Pass order to try_to_free_pages " Matthew Wilcox
2019-05-07 4:06 ` [PATCH 11/11] mm: Pass order to node_reclaim() " Matthew Wilcox
2019-05-09 1:58 ` [RFC 00/11] Remove 'order' argument from many mm functions Ira Weiny
2019-05-09 14:07 ` Matthew Wilcox
2019-05-09 16:48 ` Weiny, Ira
2019-05-09 18:29 ` Matthew Wilcox
2019-05-29 21:44 ` Ira Weiny
2019-05-09 11:07 ` Kirill A. Shutemov [this message]
2019-05-14 14:51 ` Matthew Wilcox
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