Messages in this thread Patch in this message | | | From | Vlastimil Babka <> | Subject | [PATCH 5/9] mm, slub: make reclaim_account attribute read-only | Date | Wed, 10 Jun 2020 18:31:31 +0200 |
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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 toggling 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> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Roman Gushchin <guro@fb.com> --- mm/slub.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 0108829838e7..8dd2925448ae 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
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