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[PATCH] sparc64: Reduce ptrace cache flushing

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We were flushing the D-cache excessively for ptrace() processing
and this makes debugging threads so slow as to be totally unusable.

All process page accesses via ptrace() go via access_process_vm().
This routine, for each process page, uses get_user_pages().  That
in turn does a flush_dcache_page() on the child pages before we
copy in/out the ptrace request data.

Therefore, all we need to do after the data movement is:

1) Flush the D-cache pages if the kernel maps the page to a different
   color than userspace does.
2) If we wrote to the page, we need to flush the I-cache on older cpus.

Previously we just flushed the entire cache at the end of a ptrace()
request, and that was beyond stupid.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David S. Miller
2005-04-17 18:03:11 -07:00
committed by Linus Torvalds
parent fb65b9619b
commit dadeafdfc8
2 changed files with 69 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/asm-sparc64/cacheflush.h
+14 -8
View File
@@ -49,16 +49,22 @@ extern void flush_dcache_page(struct page *page);
#define flush_icache_page(vma, pg) do { } while(0)
#define flush_icache_user_range(vma,pg,adr,len) do { } while (0)
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page));\
memcpy(dst, src, len); \
extern void flush_ptrace_access(struct vm_area_struct *, struct page *,
unsigned long uaddr, void *kaddr,
unsigned long len, int write);
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page)); \
memcpy(dst, src, len); \
flush_ptrace_access(vma, page, vaddr, src, len, 0); \
} while (0)
#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page));\
memcpy(dst, src, len); \
#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page)); \
memcpy(dst, src, len); \
flush_ptrace_access(vma, page, vaddr, dst, len, 1); \
} while (0)
#define flush_dcache_mmap_lock(mapping) do { } while (0)