lkml.org 
[lkml]   [2015]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 07/13] mm: meminit: Initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set
On Tue, 28 Apr 2015 15:37:04 +0100 Mel Gorman <mgorman@suse.de> wrote:

> +/*
> + * Deferred struct page initialisation requires some early init functions that
> + * are removed before kswapd is up and running. The feature depends on memory
> + * hotplug so put the data and code required by deferred initialisation into
> + * the __meminit section where they are preserved.
> + */
> +#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
> +#define __defermem_init __meminit
> +#define __defer_init __meminit
> +#else
> +#define __defermem_init
> +#define __defer_init __init
> +#endif

I still don't get it :(

__defermem_init:

if (CONFIG_DEFERRED_STRUCT_PAGE_INIT) {
if (CONFIG_MEMORY_HOTPLUG)
retain
} else {
retain
}

but CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on
CONFIG_MEMORY_HOTPLUG, so this becomes

if (CONFIG_DEFERRED_STRUCT_PAGE_INIT) {
retain
} else {
retain
}

which becomes

retain

so why does __defermem_init exist?



__defer_init:

if (CONFIG_DEFERRED_STRUCT_PAGE_INIT) {
if (CONFIG_MEMORY_HOTPLUG)
retain
} else {
discard
}

becomes

if (CONFIG_DEFERRED_STRUCT_PAGE_INIT) {
retain
} else {
discard
}

this one makes sense, but could be documented much more clearly!


And why does the comment refer to "and data". There is no
__defer_initdata, etc. Just not needed yet?



\
 
 \ /
  Last update: 2015-04-29 23:41    [W:0.461 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site