lkml.org 
[lkml]   [2004]   [Mar]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Lse-tech] Re: [PATCH] [0/6] HUGETLB memory commitment
On Thu, Mar 25, 2004 at 04:22:32PM -0800, Andrew Morton wrote:
> Keith Owens <kaos@sgi.com> wrote:
> >
> > FWIW, lkcd (crash dump) treats hugetlb pages as normal kernel pages and
> > dumps them, which is pointless and wastes a lot of time. To avoid
> > dumping these pages in lkcd, I had to add a PG_hugetlb flag. lkcd runs

This should already be fixed in recent versions of lkcd. It uses a
little bit of trickery to avoid an extra page flag -- hugetlb pages are
detected as "in use" as well as reserved, unlike other reserved pages
which helps identify them.

/* to track all used (compound + zero order) pages */
#define PageInuse(p) (PageCompound(p) || page_count(p))
.
.

static inline int kernel_page(struct page *p)
{
/* Need to exclude hugetlb pages. Clue: reserved but inuse */
return (PageReserved(p) && !PageInuse(p)) || (!PageLRU(p) && PageInuse(p));
}
Regards
Suparna

> > at the page level, not mm or vma, so VM_hugetlb was not available. In
> > set_hugetlb_mem_size()
> >
> > for (j = 0; j < (HPAGE_SIZE / PAGE_SIZE); j++) {
> > SetPageReserved(map);
> > SetPageHugetlb(map);
> > map++;
> > }
> >
> > In dump_base.c, I changed kernel_page(), referenced_page() and
> > unreferenced_page() to test for PageHugetlb() before PageReserved().
>
> That makes sense.
>
> > Since you are looking at identifying hugetlb pages, could any other
> > code benefit from a PG_hugetlb flag?
>
> In the overcommit code we don't actually have the page yet. We're asking
> "do we have enough memory available to honour this mmap() invokation when
> it later faults in real pages".
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by: IBM Linux Tutorials
> Free Linux tutorial presented by Daniel Robbins, President and CEO of
> GenToo technologies. Learn everything from fundamentals to system
> administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
> _______________________________________________
> Lse-tech mailing list
> Lse-tech@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lse-tech

--
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:01    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site