Commit 0798e519 authored Dec 06, 2006 by Paul Jackson Committed by Linus Torvalds Dec 07, 2006

[PATCH] memory page alloc minor cleanups



- s/freeliest/freelist/ spelling fix

- Check for NULL *z zone seems useless - even if it could happen, so
  what?  Perhaps we should have a check later on if we are faced with an
  allocation request that is not allowed to fail - shouldn't that be a
  serious kernel error, passing an empty zonelist with a mandate to not
  fail?

- Initializing 'z' to zonelist->zones can wait until after the first
  get_page_from_freelist() fails; we only use 'z' in the wakeup_kswapd()
  loop, so let's initialize 'z' there, in a 'for' loop.  Seems clearer.

- Remove superfluous braces around a break

- Fix a couple errant spaces

- Adjust indentation on the cpuset_zone_allowed() check, to match the
  lines just before it -- seems easier to read in this case.

- Add another set of braces to the zone_watermark_ok logic

From: Paul Jackson <pj@sgi.com>

  Backout one item from a previous "memory page_alloc minor cleanups" patch.
   Until and unless we are certain that no one can ever pass an empty zonelist
  to __alloc_pages(), this check for an empty zonelist (or some BUG
  equivalent) is essential.  The code in get_page_from_freelist() blow ups if
  passed an empty zonelist.

Signed-off-by: Paul Jackson <pj@sgi.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a2ce7740

mm/page_alloc.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -926,7 +926,7 @@ int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
		}

		/*
		* get_page_from_freeliest goes through the zonelist trying to allocate
		* get_page_from_freelist goes through the zonelist trying to allocate
		* a page.
		*/
		static struct page *
		@@ -960,16 +960,17 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
		else
		mark = zone->pages_high;
		if (!zone_watermark_ok(zone, order, mark,
		classzone_idx, alloc_flags))
		classzone_idx, alloc_flags)) {
		if (!zone_reclaim_mode \|\|
		!zone_reclaim(zone, gfp_mask, order))
		continue;
		}
		}

		page = buffered_rmqueue(zonelist, zone, order, gfp_mask);
		if (page) {
		if (page)
		break;
		}

		} while (*(++z) != NULL);
		return page;
		}
		@@ -1005,9 +1006,8 @@ __alloc_pages(gfp_t gfp_mask, unsigned int order,
		if (page)
		goto got_pg;

		do {
		for (z = zonelist->zones; *z; z++)
		wakeup_kswapd(*z, order);
		} while (*(++z));

		/*
		* OK, we're below the kswapd watermark and have kicked background