From: Andrew Morton <akpm@linux-foundation.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH] mm: don't call should_failslab() for !CONFIG_FAILSLAB
Date: Tue, 5 Oct 2021 14:18:32 -0700 [thread overview]
Message-ID: <20211005141832.d6f3d4e06c4ad7a06cd554dd@linux-foundation.org> (raw)
In-Reply-To: <e01e5e40-692a-519c-4cba-e3331f173c82@kernel.dk>
On Tue, 5 Oct 2021 09:31:43 -0600 Jens Axboe <axboe@kernel.dk> wrote:
> Allocations can be a very hot path, and this out-of-line function
> call is noticeable.
>
> --- a/include/linux/fault-inject.h
> +++ b/include/linux/fault-inject.h
> @@ -64,8 +64,8 @@ static inline struct dentry *fault_create_debugfs_attr(const char *name,
>
> struct kmem_cache;
>
> -int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
> #ifdef CONFIG_FAILSLAB
> +int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
> extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);
> #else
> static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
> diff --git a/mm/slab.h b/mm/slab.h
> index 58c01a34e5b8..92fd6fe01877 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -491,8 +491,10 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
>
> might_alloc(flags);
>
> +#ifdef CONFIG_FAILSLAB
> if (should_failslab(s, flags))
> return NULL;
> +#endif
Can we avoid the ifdefs here?
>
> if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
> return NULL;
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index ec2bb0beed75..c21bd447f237 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1323,6 +1323,7 @@ EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
> EXPORT_TRACEPOINT_SYMBOL(kfree);
> EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
>
> +#ifdef CONFIG_FAILSLAB
> int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
> {
> if (__should_failslab(s, gfpflags))
> @@ -1330,3 +1331,4 @@ int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
> return 0;
> }
> ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
> +#endif
Like,
--- a/include/linux/fault-inject.h~mm-dont-call-should_failslab-for-config_failslab-fix
+++ a/include/linux/fault-inject.h
@@ -68,6 +68,10 @@ struct kmem_cache;
int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);
#else
+static inline int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
+{
+ return 0;
+}
static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
{
return false;
--- a/mm/slab.h~mm-dont-call-should_failslab-for-config_failslab-fix
+++ a/mm/slab.h
@@ -491,10 +491,8 @@ static inline struct kmem_cache *slab_pr
might_alloc(flags);
-#ifdef CONFIG_FAILSLAB
if (should_failslab(s, flags))
return NULL;
-#endif
if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
return NULL;
_
next prev parent reply other threads:[~2021-10-05 21:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 15:31 [PATCH] mm: don't call should_failslab() for !CONFIG_FAILSLAB Jens Axboe
2021-10-05 21:18 ` Andrew Morton [this message]
2021-10-05 21:20 ` Jens Axboe
2021-10-07 15:32 ` Vlastimil Babka
2021-10-07 15:50 ` Jens Axboe
2021-10-07 16:36 ` Konstantin Ryabitsev
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=20211005141832.d6f3d4e06c4ad7a06cd554dd@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).