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Message-Id: <20240827190916.34242-1-urezki@gmail.com>
Date: Tue, 27 Aug 2024 21:09:16 +0200
From: "Uladzislau Rezki (Sony)" <urezki@...il.com>
To: linux-mm@...ck.org,
Andrew Morton <akpm@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Baoquan He <bhe@...hat.com>,
Christoph Hellwig <hch@...radead.org>,
Michal Hocko <mhocko@...e.com>,
Uladzislau Rezki <urezki@...il.com>,
Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: [PATCH] mm: vmalloc: Refactor vm_area_alloc_pages() function
The aim is to simplify and making the vm_area_alloc_pages()
function less confusing as it became more clogged nowadays:
- eliminate a "bulk_gfp" variable and do not overwrite a gfp
flag for bulk allocator;
- drop __GFP_NOFAIL flag for high-order-page requests on upper
layer. It becomes less spread between levels when it comes to
__GFP_NOFAIL allocations;
- add a comment about a fallback path if high-order attempt is
unsuccessful because for such cases __GFP_NOFAIL is dropped;
- fix a typo in a commit message.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
mm/vmalloc.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3f9b6bd707d2..57862865e808 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3531,8 +3531,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
unsigned int order, unsigned int nr_pages, struct page **pages)
{
unsigned int nr_allocated = 0;
- gfp_t alloc_gfp = gfp;
- bool nofail = gfp & __GFP_NOFAIL;
struct page *page;
int i;
@@ -3543,9 +3541,6 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
* more permissive.
*/
if (!order) {
- /* bulk allocator doesn't support nofail req. officially */
- gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL;
-
while (nr_allocated < nr_pages) {
unsigned int nr, nr_pages_request;
@@ -3563,12 +3558,11 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
* but mempolicy wants to alloc memory by interleaving.
*/
if (IS_ENABLED(CONFIG_NUMA) && nid == NUMA_NO_NODE)
- nr = alloc_pages_bulk_array_mempolicy_noprof(bulk_gfp,
+ nr = alloc_pages_bulk_array_mempolicy_noprof(gfp,
nr_pages_request,
pages + nr_allocated);
-
else
- nr = alloc_pages_bulk_array_node_noprof(bulk_gfp, nid,
+ nr = alloc_pages_bulk_array_node_noprof(gfp, nid,
nr_pages_request,
pages + nr_allocated);
@@ -3582,30 +3576,24 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
if (nr != nr_pages_request)
break;
}
- } else if (gfp & __GFP_NOFAIL) {
- /*
- * Higher order nofail allocations are really expensive and
- * potentially dangerous (pre-mature OOM, disruptive reclaim
- * and compaction etc.
- */
- alloc_gfp &= ~__GFP_NOFAIL;
}
/* High-order pages or fallback path if "bulk" fails. */
while (nr_allocated < nr_pages) {
- if (!nofail && fatal_signal_pending(current))
+ if (!(gfp & __GFP_NOFAIL) && fatal_signal_pending(current))
break;
if (nid == NUMA_NO_NODE)
- page = alloc_pages_noprof(alloc_gfp, order);
+ page = alloc_pages_noprof(gfp, order);
else
- page = alloc_pages_node_noprof(nid, alloc_gfp, order);
+ page = alloc_pages_node_noprof(nid, gfp, order);
+
if (unlikely(!page))
break;
/*
* Higher order allocations must be able to be treated as
- * indepdenent small pages by callers (as they can with
+ * independent small pages by callers (as they can with
* small-page vmallocs). Some drivers do their own refcounting
* on vmalloc_to_page() pages, some use page->mapping,
* page->lru, etc.
@@ -3666,7 +3654,16 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
set_vm_area_page_order(area, page_shift - PAGE_SHIFT);
page_order = vm_area_page_order(area);
- area->nr_pages = vm_area_alloc_pages(gfp_mask | __GFP_NOWARN,
+ /*
+ * Higher order nofail allocations are really expensive and
+ * potentially dangerous (pre-mature OOM, disruptive reclaim
+ * and compaction etc.
+ *
+ * Please note, the __vmalloc_node_range_noprof() falls-back
+ * to order-0 pages if high-order attempt is unsuccessful.
+ */
+ area->nr_pages = vm_area_alloc_pages((page_order ?
+ gfp_mask & ~__GFP_NOFAIL : gfp_mask) | __GFP_NOWARN,
node, page_order, nr_small_pages, area->pages);
atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
--
2.39.2
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