From 630d9c47274aa89bfa77fe6556d7818bdcb12992 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Wed, 16 Nov 2011 23:57:37 -0500 Subject: fs: reduce the use of module.h wherever possible For files only using THIS_MODULE and/or EXPORT_SYMBOL, map them onto including export.h -- or if the file isn't even using those, then just delete the include. Fix up any implicit include dependencies that were being masked by module.h along the way. Signed-off-by: Paul Gortmaker --- fs/buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index 1a30db77af3..70e2017edd7 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -29,7 +29,7 @@ #include #include #include -#include +#include #include #include #include -- cgit v1.2.3-70-g09d2 From 42be35d0390b966253136a285f507f5ad00fd9e8 Mon Sep 17 00:00:00 2001 From: Gilad Ben-Yossef Date: Wed, 28 Mar 2012 14:42:45 -0700 Subject: fs: only send IPI to invalidate LRU BH when needed In several code paths, such as when unmounting a file system (but not only) we send an IPI to ask each cpu to invalidate its local LRU BHs. For multi-cores systems that have many cpus that may not have any LRU BH because they are idle or because they have not performed any file system accesses since last invalidation (e.g. CPU crunching on high perfomance computing nodes that write results to shared memory or only using filesystems that do not use the bh layer.) This can lead to loss of performance each time someone switches the KVM (the virtual keyboard and screen type, not the hypervisor) if it has a USB storage stuck in. This patch attempts to only send an IPI to cpus that have LRU BH. Signed-off-by: Gilad Ben-Yossef Acked-by: Peter Zijlstra Cc: Alexander Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/buffer.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index 70e2017edd7..36d66653b93 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1384,10 +1384,23 @@ static void invalidate_bh_lru(void *arg) } put_cpu_var(bh_lrus); } + +static bool has_bh_in_lru(int cpu, void *dummy) +{ + struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu); + int i; + for (i = 0; i < BH_LRU_SIZE; i++) { + if (b->bhs[i]) + return 1; + } + + return 0; +} + void invalidate_bh_lrus(void) { - on_each_cpu(invalidate_bh_lru, NULL, 1); + on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1, GFP_KERNEL); } EXPORT_SYMBOL_GPL(invalidate_bh_lrus); -- cgit v1.2.3-70-g09d2