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Commit b52439c2 authored by David S. Miller's avatar David S. Miller
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[SPARC64]: Don't kill the page allocator when growing a TSB. 



Try only lightly on > 1 order allocations.

If a grow fails, we are under memory pressure, so do not try
to grow the TSB for this address space any more.

If a > 0 order TSB allocation fails on a new fork, retry using
a 0 order allocation.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 05f9ca83

arch/sparc64/mm/tsb.c

+35 −8
Original line number Diff line number Diff line
@@ -216,7 +216,8 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes) 
 *

 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers

 * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB

 * must be 512K aligned.

 * must be 512K aligned.  It also must be physically contiguous, so we

 * cannot use vmalloc().

 *

 * The idea here is to grow the TSB when the RSS of the process approaches

 * the number of entries that the current TSB can hold at once.  Currently,
@@ -228,6 +229,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long rss) 
	unsigned long size, old_size, flags;

	struct page *page;

	struct tsb *old_tsb, *new_tsb;

	unsigned long order, new_rss_limit;

	gfp_t gfp_flags;



	if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))

		max_tsb_size = (PAGE_SIZE << MAX_ORDER);
@@ -240,9 +243,37 @@ void tsb_grow(struct mm_struct *mm, unsigned long rss) 
			break;

	}



	page = alloc_pages(GFP_KERNEL, get_order(size));

	if (unlikely(!page))

	if (size == max_tsb_size)

		new_rss_limit = ~0UL;

	else

		new_rss_limit = ((size / sizeof(struct tsb)) * 3) / 4;



retry_page_alloc:

	order = get_order(size);

	gfp_flags = GFP_KERNEL;

	if (order > 1)

		gfp_flags = __GFP_NOWARN | __GFP_NORETRY;



	page = alloc_pages(gfp_flags, order);

	if (unlikely(!page)) {

		/* Not being able to fork due to a high-order TSB

		 * allocation failure is very bad behavior.  Just back

		 * down to a 0-order allocation and force no TSB

		 * growing for this address space.

		 */

		if (mm->context.tsb == NULL && order > 0) {

			size = PAGE_SIZE;

			new_rss_limit = ~0UL;

			goto retry_page_alloc;

		}



		/* If we failed on a TSB grow, we are under serious

		 * memory pressure so don't try to grow any more.

		 */

		if (mm->context.tsb != NULL)

			mm->context.tsb_rss_limit = ~0UL;

		return;

	}



	/* Mark all tags as invalid.  */

	new_tsb = page_address(page);
@@ -286,11 +317,7 @@ void tsb_grow(struct mm_struct *mm, unsigned long rss) 
		return;

	}



	if (size == max_tsb_size)

		mm->context.tsb_rss_limit = ~0UL;

	else

		mm->context.tsb_rss_limit =

			((size / sizeof(struct tsb)) * 3) / 4;

	mm->context.tsb_rss_limit = new_rss_limit;



	if (old_tsb) {

		extern void copy_tsb(unsigned long old_tsb_base,