All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dev Jain <dev.jain@arm.com>
To: akpm@linux-foundation.org
Cc: rppt@kernel.org, ryan.roberts@arm.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Dev Jain <dev.jain@arm.com>
Subject: [PATCH] mm: Remove PMD alignment constraint in execmem_vmalloc()
Date: Thu, 18 Sep 2025 15:04:53 +0530	[thread overview]
Message-ID: <20250918093453.75676-1-dev.jain@arm.com> (raw)

When using vmalloc with VM_ALLOW_HUGE_VMAP flag, it will set the alignment
to PMD_SIZE internally, if it deems huge mappings to be eligible.
Therefore, setting the alignment in execmem_vmalloc is redundant. Apart
from this, it also reduces the probability of allocation in case vmalloc
fails to allocate hugepages - in the fallback case, vmalloc tries to use
the original alignment and allocate basepages, which unfortunately will
again be PMD_SIZE passed over from execmem_vmalloc, thus constraining
the search for a free space in vmalloc region.

Therefore, remove this constraint.

Signed-off-by: Dev Jain <dev.jain@arm.com>
---
mm-selftests pass, but I am not sure if they touch execmem code, and I
have no experience with this code.

 mm/execmem.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mm/execmem.c b/mm/execmem.c
index 0822305413ec..810a4ba9c924 100644
--- a/mm/execmem.c
+++ b/mm/execmem.c
@@ -38,9 +38,6 @@ static void *execmem_vmalloc(struct execmem_range *range, size_t size,
 	if (kasan)
 		vm_flags |= VM_DEFER_KMEMLEAK;
 
-	if (vm_flags & VM_ALLOW_HUGE_VMAP)
-		align = PMD_SIZE;
-
 	p = __vmalloc_node_range(size, align, start, end, gfp_flags,
 				 pgprot, vm_flags, NUMA_NO_NODE,
 				 __builtin_return_address(0));
-- 
2.30.2



             reply	other threads:[~2025-09-18  9:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-18  9:34 Dev Jain [this message]
2025-09-18 10:33 ` [PATCH] mm: Remove PMD alignment constraint in execmem_vmalloc() Mike Rapoport
2025-09-18 13:06   ` Ryan Roberts
2025-09-21  7:39     ` Mike Rapoport
2025-09-22  6:02 ` Anshuman Khandual
2025-09-22  6:50   ` Dev Jain

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250918093453.75676-1-dev.jain@arm.com \
    --to=dev.jain@arm.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=rppt@kernel.org \
    --cc=ryan.roberts@arm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.