From: Vlastimil Babka <vbabka@suse.cz>
To: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@android.com, vinmenon@codeaurora.org,
Kees Cook <keescook@chromium.org>,
Matthew Garrett <mjg59@google.com>,
Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
Vijayanand Jitta <vjitta@codeaurora.org>
Subject: [RFC PATCH 5/5] mm, slub: make reclaim_account attribute read-only
Date: Tue, 2 Jun 2020 16:15:19 +0200 [thread overview]
Message-ID: <20200602141519.7099-6-vbabka@suse.cz> (raw)
In-Reply-To: <20200602141519.7099-1-vbabka@suse.cz>
The attribute reflects the SLAB_RECLAIM_ACCOUNT cache flag. It's not clear why
this attribute was writable in the first place, as it's tied to how the cache
is used by its creator, it's not a user tunable. Furthermore:
- it affects slab merging, but that's not being checked while toggled
- if affects whether __GFP_RECLAIMABLE flag is used to allocate page, but
the runtime toggle doesn't update allocflags
- it affects cache_vmstat_idx() so runtime toggle might lead to incosistency
of NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE
Thus make it read-only.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/slub.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 38dd6f3ebb04..d4a9a097da50 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5223,16 +5223,7 @@ static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
{
return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
}
-
-static ssize_t reclaim_account_store(struct kmem_cache *s,
- const char *buf, size_t length)
-{
- s->flags &= ~SLAB_RECLAIM_ACCOUNT;
- if (buf[0] == '1')
- s->flags |= SLAB_RECLAIM_ACCOUNT;
- return length;
-}
-SLAB_ATTR(reclaim_account);
+SLAB_ATTR_RO(reclaim_account);
static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
{
--
2.26.2
next prev parent reply other threads:[~2020-06-02 14:16 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 14:15 [RFC PATCH 0/5] replace runtime slub_debug toggling with more capable boot parameter Vlastimil Babka
2020-06-02 14:15 ` [RFC PATCH 1/5] mm, slub: extend slub_debug syntax for multiple blocks Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-08 16:58 ` Vlastimil Babka
2020-06-02 14:15 ` [RFC PATCH 2/5] mm, slub: make some slub_debug related attributes read-only Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-06 0:32 ` Roman Gushchin
2020-06-02 14:15 ` [RFC PATCH 3/5] mm, slub: remove runtime allocation order changes Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-06 0:32 ` Roman Gushchin
2020-06-02 14:15 ` [RFC PATCH 4/5] mm, slub: make remaining slub_debug related attributes read-only Vlastimil Babka
2020-06-05 21:07 ` Kees Cook
2020-06-06 0:33 ` Roman Gushchin
2020-06-02 14:15 ` Vlastimil Babka [this message]
2020-06-05 21:07 ` [RFC PATCH 5/5] mm, slub: make reclaim_account attribute read-only Kees Cook
2020-06-06 0:34 ` Roman Gushchin
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