From 6ebfe5864ae65ad31e1e5526f0f45a5f735c9a5b Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Wed, 26 Jun 2013 17:26:01 -0700 Subject: mm: add a field to store names for private anonymous memory Userspace processes often have multiple allocators that each do anonymous mmaps to get memory. When examining memory usage of individual processes or systems as a whole, it is useful to be able to break down the various heaps that were allocated by each layer and examine their size, RSS, and physical memory usage. This patch adds a user pointer to the shared union in vm_area_struct that points to a null terminated string inside the user process containing a name for the vma. vmas that point to the same address will be merged, but vmas that point to equivalent strings at different addresses will not be merged. Userspace can set the name for a region of memory by calling prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name); Setting the name to NULL clears it. The names of named anonymous vmas are shown in /proc/pid/maps as [anon:] and in /proc/pid/smaps in a new "Name" field that is only present for named vmas. If the userspace pointer is no longer valid all or part of the name will be replaced with "". The idea to store a userspace pointer to reduce the complexity within mm (at the expense of the complexity of reading /proc/pid/mem) came from Dave Hansen. This results in no runtime overhead in the mm subsystem other than comparing the anon_name pointers when considering vma merging. The pointer is stored in a union with fieds that are only used on file-backed mappings, so it does not increase memory usage. Change-Id: Ie2ffc0967d4ffe7ee4c70781313c7b00cf7e3092 Signed-off-by: Colin Cross --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mempolicy.c') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 74310017296..7b349aafe79 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -728,7 +728,7 @@ static int mbind_range(struct mm_struct *mm, unsigned long start, ((vmstart - vma->vm_start) >> PAGE_SHIFT); prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff, - new_pol); + new_pol, vma_get_anon_name(name)); if (prev) { vma = prev; next = vma->vm_next; -- cgit v1.2.3 From 527aae529118f2cbe99c945ffe74be1c04ceaba6 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Wed, 30 Oct 2013 13:14:12 -0700 Subject: mm: fix anon vma naming Fix two bugs caused by merging anon vma_naming, a typo in mempolicy.c and a bad merge in sys.c. Change-Id: Ia4ced447d50573e68195e95ea2f2b4d9456b8a90 Signed-off-by: Colin Cross --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mempolicy.c') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 7b349aafe79..bf12a3fc120 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -728,7 +728,7 @@ static int mbind_range(struct mm_struct *mm, unsigned long start, ((vmstart - vma->vm_start) >> PAGE_SHIFT); prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff, - new_pol, vma_get_anon_name(name)); + new_pol, vma_get_anon_name(vma)); if (prev) { vma = prev; next = vma->vm_next; -- cgit v1.2.3