diff options
| author | Christophe JAILLET <christophe.jaillet@wanadoo.fr> | 2022-07-21 00:26:36 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-09-01 19:17:14 +0300 |
| commit | 61742a7cd5b194d2cc52d78de8ec6967634a4cd6 (patch) | |
| tree | 35fcdafc0c2792e250f4f6425000b739e092e47e | |
| parent | 6bb7ea3afd3eaae95eda6ef5589c3087f2cd70d8 (diff) | |
| download | linux-61742a7cd5b194d2cc52d78de8ec6967634a4cd6.tar.xz | |
devres: Slightly optimize alloc_dr()
If the gfp flag used for the memory allocation already has __GFP_ZERO,
then there is no need to explicitly clear the "struct devres_node". It is
already zeroed.
This saves a few cycles when using devm_zalloc() and co.
In the case of devres_alloc() (which calls __devres_alloc_node()), the
compiler could remove the test and the memset() because it should be able
to see that the __GFP_ZERO flag is set.
So this would make the code both faster and smaller.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/d255bd871484e63cdd628e819f929e2df59afb02.1658352383.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/base/devres.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/base/devres.c b/drivers/base/devres.c index 864d0b3f566e..4ab2b50ee38f 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -117,7 +117,9 @@ static __always_inline struct devres * alloc_dr(dr_release_t release, if (unlikely(!dr)) return NULL; - memset(dr, 0, offsetof(struct devres, data)); + /* No need to clear memory twice */ + if (!(gfp & __GFP_ZERO)) + memset(dr, 0, offsetof(struct devres, data)); INIT_LIST_HEAD(&dr->node.entry); dr->node.release = release; |