Re: [PATCH 3/5] hugetlb: try to search again if it is really needed
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2012-02-01 22:43:56
Also in:
lkml
On Fri, 13 Jan 2012 19:45:45 +0800 Xiao Guangrong [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Search again only if some holes may be skipped in the first time Signed-off-by: Xiao Guangrong <redacted> --- arch/x86/mm/hugetlbpage.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-)diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index e12debc..6bf5735 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c@@ -309,9 +309,8 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, struct hstate *h = hstate_file(file); struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - unsigned long base = mm->mmap_base, addr = addr0; + unsigned long base = mm->mmap_base, addr = addr0, start_addr;
grr. The multiple-definitions-per-line thing is ugly, makes for more patch conflicts and reduces opportunities to add useful comments.
--- a/arch/x86/mm/hugetlbpage.c~hugetlb-try-to-search-again-if-it-is-really-needed-fix
+++ a/arch/x86/mm/hugetlbpage.c@@ -309,7 +309,9 @@ static unsigned long hugetlb_get_unmappe struct hstate *h = hstate_file(file); struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - unsigned long base = mm->mmap_base, addr = addr0, start_addr; + unsigned long base = mm->mmap_base; + unsigned long addr = addr0; + unsigned long start_addr; unsigned long largest_hole = mm->cached_hole_size; /* don't allow allocations above current base */
_
quoted hunk ↗ jump to hunk
unsigned long largest_hole = mm->cached_hole_size; - int first_time = 1; /* don't allow allocations above current base */ if (mm->free_area_cache > base)@@ -322,6 +321,8 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, mm->free_area_cache = base; } try_again: + start_addr = mm->free_area_cache; + /* make sure it can fit in the remaining address space */ if (mm->free_area_cache < len) goto fail;@@ -357,10 +358,9 @@ fail: * if hint left us with no space for the requested * mapping then try again: */ - if (first_time) { + if (start_addr != base) { mm->free_area_cache = base; largest_hole = 0; - first_time = 0; goto try_again;
The code used to retry a single time. With this change the retrying is potentially infinite. What is the reason for this change? What is the potential for causing a lockup? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>