Commit b716ad95 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Linus Torvalds
Browse files

mm: search from free_area_cache for the bigger size 



If the required size is bigger than cached_hole_size it is better to
search from free_area_cache - it is easier to get a free region,
specifically for the 64 bit process whose address space is large enough

Do it just as hugetlb_get_unmapped_area_topdown() in arch/x86/mm/hugetlbpage.c

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f44d2198

arch/x86/kernel/sys_x86_64.c

+17 −17
Original line number Diff line number Diff line
@@ -195,7 +195,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
{

	struct vm_area_struct *vma;

	struct mm_struct *mm = current->mm;

	unsigned long addr = addr0;

	unsigned long addr = addr0, start_addr;



	/* requested length too big for entire address space */

	if (len > TASK_SIZE)
@@ -223,25 +223,14 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
		mm->free_area_cache = mm->mmap_base;

	}



try_again:

	/* either no address requested or can't fit in requested address hole */

	addr = mm->free_area_cache;



	/* make sure it can fit in the remaining address space */

	if (addr > len) {

		unsigned long tmp_addr = align_addr(addr - len, filp,

						    ALIGN_TOPDOWN);



		vma = find_vma(mm, tmp_addr);

		if (!vma || tmp_addr + len <= vma->vm_start)

			/* remember the address as a hint for next time */

			return mm->free_area_cache = tmp_addr;

	}



	if (mm->mmap_base < len)

		goto bottomup;

	start_addr = addr = mm->free_area_cache;



	addr = mm->mmap_base-len;

	if (addr < len)

		goto fail;



	addr -= len;

	do {

		addr = align_addr(addr, filp, ALIGN_TOPDOWN);
@@ -263,6 +252,17 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
		addr = vma->vm_start-len;

	} while (len < vma->vm_start);



fail:

	/*

	 * if hint left us with no space for the requested

	 * mapping then try again:

	 */

	if (start_addr != mm->mmap_base) {

		mm->free_area_cache = mm->mmap_base;

		mm->cached_hole_size = 0;

		goto try_again;

	}



bottomup:

	/*

	 * A failed mmap() very likely causes application failure,

mm/mmap.c

+21 −15
Original line number Diff line number Diff line
@@ -1442,7 +1442,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
{

	struct vm_area_struct *vma;

	struct mm_struct *mm = current->mm;

	unsigned long addr = addr0;

	unsigned long addr = addr0, start_addr;



	/* requested length too big for entire address space */

	if (len > TASK_SIZE)
@@ -1466,22 +1466,14 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
 		mm->free_area_cache = mm->mmap_base;

 	}



try_again:

	/* either no address requested or can't fit in requested address hole */

	addr = mm->free_area_cache;



	/* make sure it can fit in the remaining address space */

	if (addr > len) {

		vma = find_vma(mm, addr-len);

		if (!vma || addr <= vma->vm_start)

			/* remember the address as a hint for next time */

			return (mm->free_area_cache = addr-len);

	}



	if (mm->mmap_base < len)

		goto bottomup;

	start_addr = addr = mm->free_area_cache;



	addr = mm->mmap_base-len;

	if (addr < len)

		goto fail;



	addr -= len;

	do {

		/*

		 * Lookup failure means no vma is above this address,
@@ -1501,7 +1493,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
		addr = vma->vm_start-len;

	} while (len < vma->vm_start);



bottomup:

fail:

	/*

	 * if hint left us with no space for the requested

	 * mapping then try again:

	 *

	 * Note: this is different with the case of bottomup

	 * which does the fully line-search, but we use find_vma

	 * here that causes some holes skipped.

	 */

	if (start_addr != mm->mmap_base) {

		mm->free_area_cache = mm->mmap_base;

		mm->cached_hole_size = 0;

		goto try_again;

	}



	/*

	 * A failed mmap() very likely causes application failure,

	 * so fall back to the bottom-up function here. This scenario

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