linux-kernel - [PATCH v1 5/6] mm/page_alloc: forward the gfp flags from alloc_contig_range() to post_alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241202125812.561028-6-david@redhat.com>
Date: Mon,  2 Dec 2024 13:58:11 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	linuxppc-dev@...ts.ozlabs.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Oscar Salvador <osalvador@...e.de>,
	Zi Yan <ziy@...dia.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Naveen N Rao <naveen@...nel.org>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>
Subject: [PATCH v1 5/6] mm/page_alloc: forward the gfp flags from alloc_contig_range() to post_alloc_hook()

In the __GFP_CONT case, we already pass the gfp_flags to
prep_new_page()->post_alloc_hook(). However, in the !__GFP_CONT case, we
essentially pass only hardcoded __GFP_MOVABLE to post_alloc_hook(),
preventing some action modifiers from being effective..

Let's pass our now properly adjusted gfp flags there as well.

This way, we can now support __GFP_ZERO for alloc_contig_*().

As a side effect, we now also support __GFP_SKIP_ZERO and__GFP_ZEROTAGS;
but we'll keep the more special stuff (KASAN, NOLOCKDEP) disabled for
now.

It's worth nothing that with __GFP_ZERO, we might unnecessarily zero pages
when we have to release part of our range using free_contig_range() again.
This can be optimized in the future, if ever required; the caller we'll
be converting (powernv/memtrace) next won't trigger this.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/page_alloc.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 54594cc4f650..71d70bc0ad79 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6364,7 +6364,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
 	return (ret < 0) ? ret : 0;
 }
 
-static void split_free_pages(struct list_head *list)
+static void split_free_pages(struct list_head *list, gfp_t gfp_mask)
 {
 	int order;
 
@@ -6375,7 +6375,7 @@ static void split_free_pages(struct list_head *list)
 		list_for_each_entry_safe(page, next, &list[order], lru) {
 			int i;
 
-			post_alloc_hook(page, order, __GFP_MOVABLE);
+			post_alloc_hook(page, order, gfp_mask);
 			set_page_refcounted(page);
 			if (!order)
 				continue;
@@ -6393,7 +6393,8 @@ static void split_free_pages(struct list_head *list)
 static int __alloc_contig_verify_gfp_mask(gfp_t gfp_mask, gfp_t *gfp_cc_mask)
 {
 	const gfp_t reclaim_mask = __GFP_IO | __GFP_FS | __GFP_RECLAIM;
-	const gfp_t action_mask = __GFP_COMP | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
+	const gfp_t action_mask = __GFP_COMP | __GFP_RETRY_MAYFAIL | __GFP_NOWARN |
+				  __GFP_ZERO | __GFP_ZEROTAGS | __GFP_SKIP_ZERO;
 	const gfp_t cc_action_mask = __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
 
 	/*
@@ -6541,7 +6542,7 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
 	}
 
 	if (!(gfp_mask & __GFP_COMP)) {
-		split_free_pages(cc.freepages);
+		split_free_pages(cc.freepages, gfp_mask);
 
 		/* Free head and tail (if any) */
 		if (start != outer_start)
-- 
2.47.1