https://git.reactos.org/?p=reactos.git;a=commitdiff;h=b3e9c8972553b040d1b43dd96406d28ebd5b953f
commit b3e9c8972553b040d1b43dd96406d28ebd5b953f Author: Jérôme Gardou <[email protected]> AuthorDate: Mon Jun 7 19:28:51 2021 +0200 Commit: Jérôme Gardou <[email protected]> CommitDate: Fri Jun 25 10:28:51 2021 +0200 [NTOS:MM] Simplify refcounting when adding/deleting a page in a shared segment CORE-17544 --- ntoskrnl/cache/section/sptab.c | 13 +++++++++++-- ntoskrnl/mm/rmap.c | 3 --- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/ntoskrnl/cache/section/sptab.c b/ntoskrnl/cache/section/sptab.c index 0877fb085f6..b0125f26b0e 100644 --- a/ntoskrnl/cache/section/sptab.c +++ b/ntoskrnl/cache/section/sptab.c @@ -204,6 +204,16 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment, OldEntry, Entry); + /* Manage ref on segment */ + if (Entry && !OldEntry) + { + InterlockedIncrement64(Segment->ReferenceCount); + } + if (OldEntry && !Entry) + { + MmDereferenceSegment(Segment); + } + if (Entry && !IS_SWAP_FROM_SSE(Entry)) { /* We have a valid entry. See if we must do something */ @@ -223,7 +233,6 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment, * Add the Rmap and take a ref on the segment. */ MmSetSectionAssociation(PFN_FROM_SSE(Entry), Segment, Offset); - InterlockedIncrement64(Segment->ReferenceCount); if (Offset->QuadPart >= (Segment->LastPage << PAGE_SHIFT)) Segment->LastPage = (Offset->QuadPart >> PAGE_SHIFT) + 1; @@ -233,7 +242,6 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment, { /* We're switching to an invalid entry from a valid one */ MmDeleteSectionAssociation(PFN_FROM_SSE(OldEntry)); - MmDereferenceSegment(Segment); if (Offset->QuadPart == ((Segment->LastPage - 1ULL) << PAGE_SHIFT)) { @@ -363,6 +371,7 @@ MmGetSectionAssociation(PFN_NUMBER Page, Offset->QuadPart = PageTable->FileOffset.QuadPart + ((ULONG64)RawOffset << PAGE_SHIFT); ASSERT(PFN_FROM_SSE(PageTable->PageEntries[RawOffset]) == Page); + InterlockedIncrement64(Segment->ReferenceCount); } return Segment; diff --git a/ntoskrnl/mm/rmap.c b/ntoskrnl/mm/rmap.c index 64758cc5b89..e27e31de820 100644 --- a/ntoskrnl/mm/rmap.c +++ b/ntoskrnl/mm/rmap.c @@ -300,7 +300,6 @@ WriteSegment: Released = MmCheckDirtySegment(Segment, &SegmentOffset, FALSE, TRUE); MmUnlockSectionSegment(Segment); - MmDereferenceSegment(Segment); if (Released) @@ -475,8 +474,6 @@ MmGetSegmentRmap(PFN_NUMBER Page, PULONG RawOffset) MiReleasePfnLock(OldIrql); return NULL; } - - InterlockedIncrement64(Result->Segment->ReferenceCount); MiReleasePfnLock(OldIrql); return Result; }
