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authorAlexey Dobriyan <adobriyan@gmail.com>2018-02-07 00:37:28 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-07 03:32:43 +0100
commit15b158b4e6274351fc3cf652cbabc57104efb547 (patch)
treeb39beb6e526de60b5a89bd27c5419f7fbd7ead3d /fs/proc
parentfs/proc: use __ro_after_init (diff)
downloadlinux-15b158b4e6274351fc3cf652cbabc57104efb547.tar.xz
linux-15b158b4e6274351fc3cf652cbabc57104efb547.zip
proc: spread likely/unlikely a bit
use_pde() is used at every open/read/write/... of every random /proc file. Negative refcount happens only if PDE is being deleted by module (read: never). So it gets "likely". unuse_pde() gets "unlikely" for the same reason. close_pdeo() gets unlikely as the completion is filled only if there is a race between PDE removal and close() (read: never ever). It even saves code on x86_64 defconfig: add/remove: 0/0 grow/shrink: 1/2 up/down: 2/-20 (-18) Function old new delta close_pdeo 183 185 +2 proc_reg_get_unmapped_area 119 111 -8 proc_reg_poll 85 73 -12 Link: http://lkml.kernel.org/r/20180104175657.GA5204@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/inode.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index c5c8e7af5520..6e8724958116 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -129,12 +129,12 @@ enum {BIAS = -1U<<31};
static inline int use_pde(struct proc_dir_entry *pde)
{
- return atomic_inc_unless_negative(&pde->in_use);
+ return likely(atomic_inc_unless_negative(&pde->in_use));
}
static void unuse_pde(struct proc_dir_entry *pde)
{
- if (atomic_dec_return(&pde->in_use) == BIAS)
+ if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
complete(pde->pde_unload_completion);
}
@@ -167,7 +167,7 @@ static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
spin_lock(&pde->pde_unload_lock);
/* After ->release. */
list_del(&pdeo->lh);
- if (pdeo->c)
+ if (unlikely(pdeo->c))
complete(pdeo->c);
kfree(pdeo);
}
@@ -421,7 +421,7 @@ static const char *proc_get_link(struct dentry *dentry,
struct delayed_call *done)
{
struct proc_dir_entry *pde = PDE(inode);
- if (unlikely(!use_pde(pde)))
+ if (!use_pde(pde))
return ERR_PTR(-EINVAL);
set_delayed_call(done, proc_put_link, pde);
return pde->data;